Date   

1925 SB 9 QCGB question

glenn brooks <brooks.glenn@...>
 

Just cleaning up a NOS 1925 SB 9, with quick change gear box. This model has the lever protruding out the top of the gear box. Nice old lathe that has been in storage most its life.

Iam just now loosening up the gears and levers and turning everything by hand.

Can some one confirm what this lever accomplishes? For example, does this lever, on top of the gear box, engage and dis engage the lead screw, or drive the apron??

If so, can it be engaged/disengaged while the machine is running, or only when stopped?

BTW, I have the SB How to Run A Lathe book, but it is a 1950’s version and doesn’t discuss this earlymday gear box set up...

Thanks
Glenn


Re: 9” FOR-REV-STOP switch

Guenther Paul
 

I have one on my 16" The buttons are On-stop-reverse relays have to be used on mine 

GP


On Sunday, October 18, 2020, 05:45:12 PM EDT, George Meinschein <bustedguns@...> wrote:


Group,
Has anyone here ever handled one of the original pushbutton switches that mount in the rectangular projection from the back gear cover?  I’m curious as to how the switch operated. Did the buttons operate a slide switch via some kind of cam?  Function wise, it looks like a DPDT switch with on-off-on action would do the trick for single phase motors and those are readily available in a rocker configuration. I’d rather see something that looks more like the original push button setup than a rocker switch though.  That led me to thinking that maybe I could make the pushbuttons out of red and black solid pvc rod (or something similar) and then configure a lever arrangement for the pushbuttons to operate the rocker switch.  I know that the whole project could be done with 3 individual momentary contact pushbutton switches and an electronic control unit, but where’s the fun in that?  Thoughts and comments please.
Thanks,
‘George


9” FOR-REV-STOP switch

George Meinschein
 

Group,
Has anyone here ever handled one of the original pushbutton switches that mount in the rectangular projection from the back gear cover?  I’m curious as to how the switch operated. Did the buttons operate a slide switch via some kind of cam?  Function wise, it looks like a DPDT switch with on-off-on action would do the trick for single phase motors and those are readily available in a rocker configuration. I’d rather see something that looks more like the original push button setup than a rocker switch though.  That led me to thinking that maybe I could make the pushbuttons out of red and black solid pvc rod (or something similar) and then configure a lever arrangement for the pushbuttons to operate the rocker switch.  I know that the whole project could be done with 3 individual momentary contact pushbutton switches and an electronic control unit, but where’s the fun in that?  Thoughts and comments please.
Thanks,
‘George


Re: 408-Y

bob11x
 

They are listed on Ebay if anyone has an interest.

https://www.ebay.com/itm/South-Bend-Lathe-Change-Gears-18DP/174484157832?hash=item28a010f588:g:pFQAAOSw8vtfi6RA


Re: 9inch c to a conversion

mike allen
 

        this may not be relevant but there were more than one type of 9" SB lathe

        animal

On 10/17/2020 9:53 AM, john kling via groups.io wrote:
Just to add a bit. The crossfeed  leadscrew for the A and B lathes has a gear at the end which meshes with a gear in the apron which serves to turn the crossfeed lead screw. The  C model which does not have power cross feed and does not have the gear. My lathe is a 415 not technically a model C. This might be why some work wasa needed to give clearance for the gear on the cross feed lead screw.

On Saturday, October 17, 2020, 12:47:21 AM EDT, john kling via groups.io <jkling222@...> wrote:


As I recall might  be a  difference and some filing was required to allow the gear on the different cross feed screw to mesh with that in the apron.

On Friday, October 16, 2020, 9:07:26 PM EDT, Patrick Murphy via groups.io <p.murphy22@...> wrote:


Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.


Re: 9inch c to a conversion

Steve Wells
 

John, you are right on the money when stating you have a No 15 Workshop, not a Model C. As Patrick suspects, the beds had several
revisions between the No 5, No 15, and the Model C, the lower area he is questioning does have to be milled for clearance for the A/B Power
Feed Apron, a lot on the No 5, less on the No 15 depending on the serial number to bed revision date. Both can be converted, but you need a No 15 or
Model C saddle with the lock on the front. A 1936 should have bed style B-7 with less clearance problems. You still may have to grind the front bed foot area
where the QC box sits, it hits the earlier B-5 bed casting.
 
Steve 
 

From: john kling via groups.io
Sent: Saturday, October 17, 2020 12:53 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] 9inch c to a conversion
 
Just to add a bit. The crossfeed  leadscrew for the A and B lathes has a gear at the end which meshes with a gear in the apron which serves to turn the crossfeed lead screw. The  C model which does not have power cross feed and does not have the gear. My lathe is a 415 not technically a model C. This might be why some work wasa needed to give clearance for the gear on the cross feed lead screw.
 
On Saturday, October 17, 2020, 12:47:21 AM EDT, john kling via groups.io <jkling222@...> wrote:
 
 
As I recall might  be a  difference and some filing was required to allow the gear on the different cross feed screw to mesh with that in the apron.
 
On Friday, October 16, 2020, 9:07:26 PM EDT, Patrick Murphy via groups.io <p.murphy22@...> wrote:
 
 
Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.


Re: 9inch c to a conversion

Louis
 

I just looked at my Series N from the same era and there's very little clearance between that metal cover and the base of the bed. Maybe 50 thou or so. I would guess your bed might just be a bit wide due to variance in the castings and it worked fine for the model C but not for your changes. If it was me I would just trim the base slightly. 


Re: 9inch c to a conversion

john kling
 

Just to add a bit. The crossfeed  leadscrew for the A and B lathes has a gear at the end which meshes with a gear in the apron which serves to turn the crossfeed lead screw. The  C model which does not have power cross feed and does not have the gear. My lathe is a 415 not technically a model C. This might be why some work wasa needed to give clearance for the gear on the cross feed lead screw.

On Saturday, October 17, 2020, 12:47:21 AM EDT, john kling via groups.io <jkling222@...> wrote:


As I recall might  be a  difference and some filing was required to allow the gear on the different cross feed screw to mesh with that in the apron.

On Friday, October 16, 2020, 9:07:26 PM EDT, Patrick Murphy via groups.io <p.murphy22@...> wrote:


Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.


Re: 9inch c to a conversion

Glen Ruch
 

I don't believe all parts were manufactured to thousands precision.  I believe there was a lot of hand fitting of parts in assembly.  Nor do I believe they evaluated the various tolerance stack ups.

I replaced the back gear handle on my 9 inch C workbench lathe.  I ended up re-taper reaming the handle eccentric to fit on the back gear axle.  Unfortunately when I was ready to replace the back gear assembly, it no longer fit between the eccentrics.  It currently waits for me to decide how I want to make it fit, either by shortening the back gear assembly or the eccentrics.

Regards.

On 10/17/20 12:47 AM, john kling via groups.io wrote:
As I recall might  be a  difference and some filing was required to allow the gear on the different cross feed screw to mesh with that in the apron.

On Friday, October 16, 2020, 9:07:26 PM EDT, Patrick Murphy via groups.io <p.murphy22@...> wrote:


Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.



Re: 9inch c to a conversion

john kling
 

As I recall might  be a  difference and some filing was required to allow the gear on the different cross feed screw to mesh with that in the apron.

On Friday, October 16, 2020, 9:07:26 PM EDT, Patrick Murphy via groups.io <p.murphy22@...> wrote:


Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.


9inch c to a conversion

Patrick Murphy
 

Hi  all i am in need of some info. Does anyone know if the saddle on the A and C are the  same. I am converting C to an A and am at the assembly stage and the aprin  is rubbing on the bottom .edge  of the bed its just barely rubbing on the tin cover of the worm. The lathe is a 1936 vintage and is in mint condition so I thought I would convert it to an A. I bought the parts on Ebay and was lucky that all I bought   were in very good shape. I am wondering if the bed castings on earlier lathes were a little wider at the bottom, if that is the problem I can trim the casting but I want to make sure there is no problem with the carriage and aprin

.


Re: Metric gears for 13”

m. allan noah
 

Steve- given that the numbers are the same as the double tumbler 13,
the metric setup is the same:

Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan
On Mon, Oct 12, 2020 at 9:10 AM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, yes, all numbers you listed are correct.

Steve Haskell

On Oct 12, 2020, at 8:23 AM, m. allan noah <kitno455@gmail.com> wrote:

Steve, I assume your lathe has a 24 tooth stud gear, a 64 tooth screw
gear, a 6 tpi leadscrew, and cuts 8-224 tpi with the 24 tooth gear
installed. Can you verify?

allan

On Mon, Oct 12, 2020 at 8:06 AM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Thanks Allan, let me know if you need any information about my lathe from me.

Steve Haskell

On Oct 11, 2020, at 7:37 PM, m. allan noah <kitno455@gmail.com> wrote:
Steven, you asked about a double tumbler machines, thats a bit
different, let me see what i can do.

allan

On Sun, Oct 11, 2020 at 7:26 PM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:
James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Re: Metric gears for 13”

Steven H
 

Allan, yes, all numbers you listed are correct.

Steve Haskell

On Oct 12, 2020, at 8:23 AM, m. allan noah <kitno455@gmail.com> wrote:

Steve, I assume your lathe has a 24 tooth stud gear, a 64 tooth screw
gear, a 6 tpi leadscrew, and cuts 8-224 tpi with the 24 tooth gear
installed. Can you verify?

allan

On Mon, Oct 12, 2020 at 8:06 AM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Thanks Allan, let me know if you need any information about my lathe from me.

Steve Haskell

On Oct 11, 2020, at 7:37 PM, m. allan noah <kitno455@gmail.com> wrote:
Steven, you asked about a double tumbler machines, thats a bit
different, let me see what i can do.

allan

On Sun, Oct 11, 2020 at 7:26 PM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:
James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"





Re: Metric gears for 13”

m. allan noah
 

Steve, I assume your lathe has a 24 tooth stud gear, a 64 tooth screw
gear, a 6 tpi leadscrew, and cuts 8-224 tpi with the 24 tooth gear
installed. Can you verify?

allan

On Mon, Oct 12, 2020 at 8:06 AM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Thanks Allan, let me know if you need any information about my lathe from me.

Steve Haskell

On Oct 11, 2020, at 7:37 PM, m. allan noah <kitno455@gmail.com> wrote:

Steven, you asked about a double tumbler machines, thats a bit
different, let me see what i can do.

allan

On Sun, Oct 11, 2020 at 7:26 PM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:
James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Re: Metric gears for 13”

Steven H
 

Thanks Allan, let me know if you need any information about my lathe from me.

Steve Haskell

On Oct 11, 2020, at 7:37 PM, m. allan noah <kitno455@gmail.com> wrote:

Steven, you asked about a double tumbler machines, thats a bit
different, let me see what i can do.

allan

On Sun, Oct 11, 2020 at 7:26 PM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:
James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"





Re: Metric gears for 13”

m. allan noah
 

Steven, you asked about a double tumbler machines, thats a bit
different, let me see what i can do.

allan

On Sun, Oct 11, 2020 at 7:26 PM Steven H via groups.io
<stevesmachining=aol.com@groups.io> wrote:

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:

James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"









--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Re: Metric gears for 13”

Steven H
 

Allan, thanks for the info.

Steve Haskell
Troy, MI

On Oct 11, 2020, at 6:18 PM, m. allan noah <kitno455@gmail.com> wrote:

James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan


On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"










--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"





Re: Metric gears for 13”

m. allan noah
 

James, the answer has not changed much since the last time you asked,
in Jan of 2019 :) The 16" single tumbler machines are similar to the
13, with a 6 TPI leadscrew, and either an 18 or 36 tooth stud gear.
Swapping to a 17 or 34 tooth gear should do the trick.

Here's a link to a thread at PM where this was discussed:
https://www.practicalmachinist.com/vb/south-bend-lathes/metric-threads-16-sb-231828/

Let me know if you have any questions
allan

On Tue, Oct 6, 2020 at 11:30 PM James Rice <james.rice@gmail.com> wrote:

I have a South Bend 16 with a single tumbler gearbox. Does anyone know the gears I would need to cut metric threads. The factory used to offer a setup but it was sold by inquiry only.

James

On Tue, Oct 6, 2020 at 10:26 PM Steven H via groups.io <stevesmachining=aol.com@groups.io> wrote:

Hi Allan,
I have a 16” South Bend with dual lever QC gearbox. Would you be willing to make the same metric thread calculations for the 16” SB? I would greatly appreciate it.

Steve Haskell
Troy, MI

On Oct 6, 2020, at 9:29 PM, m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:
Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Re: 408-Y

bob11x
 
Edited

I had a chance to check closer yesterday.  I cannot seem to find the spindle or head stock (?!) but everything else is there including the rear drive pulley mount.
Back gear is missing 1 tooth, and the idler for it is missing 1/2 of a tooth - not sure how they did that.
Change gears: Looks like a total of 13 (12 + 1 mounted on arm)
5/8 keyed center
Calculates to 18dp
32 -  1 15/16
40 -  2 5/16
44 -  2 9/16
46 -  2 11/16
48 -  2 13/16
52 -  3
56 -  3 3/16
60 -  3 7/16
64 -  3 11/16
72 -  4 1/8
80 -  4 9/16
81 -  4 5/8 approx
92 -  5 3/16

I am in no need of this stuff and would like to clear some space.  Reasonable price?


Re: Metric gears for 13”

m. allan noah
 

The simplest way to get a reasonable approximation of most metric
threads on the double tumbler 10L requires adding three gears.
Unfortunately, Boston Gear does not have nearly as many 16DP gears in
production as they once did. So, you might have to make them. The
basic idea is to replace the 56 tooth gearbox input (AKA, 'screw
gear') with a 79 tooth gear instead. With the normal 40 tooth stud
gear still in place, this makes your leadscrew act like it is 2.25mm
pitch. You can then produce 13 common metric pitches with 0.028%
error:

Gearbox, MM, %Err
72 0.25 0.028
60 0.30 0.028
40 0.45 0.028
36 0.50 0.028
30 0.60 0.028
24 0.75 0.028
20 0.90 0.028
18 1.00 0.028
12 1.50 0.028
9 2.00 0.028
6 3.00 0.028
4.5 4.00 0.028
4 4.50 0.028

Then, if you replace the 40 tooth stud gear with a 50, you can pick up
a few other common pitches:

Gearbox, MM, %Err
18 1.25 0.028
9 2.50 0.028
4.5 5.00 0.028

And similarly if you use a 35 instead:

Gearbox, MM, %Err
9 1.75 0.029
4.5 3.50 0.029

There are other ways to do this, some of them also use only 3 gears.
So, you have access to some 16DP gears, or want some other pitch not
listed, let me know. In particular, be on the lookout for a set of
loose change gears from a 9 Junior.

allan

On Tue, Oct 6, 2020 at 9:25 PM m. allan noah <kitno455@gmail.com> wrote:

Yes, something similar can be done on the 10L, but it is not quite as
simple as on the 13 and Fourteen. We need to replace both the stud and
the screw gear to get reasonable quantities of pitches. There are
nearly an infinite number of ways to do this, let me think about it
and get back to you.

allan

On Mon, Oct 5, 2020 at 9:11 AM Nathan Baynes <natebaynes@gmail.com> wrote:

Allan,
Do you have another break down like this for the heavy 10? Or is it the same? I will have to go check my lead screw pitch??
Natebaynes@gmail.com
On Oct 4, 2020, at 7:19 PM, m. allan noah <kitno455@gmail.com> wrote:

Rick-

The real trick is to use a 34 tooth stud gear instead of the 24 or 48.
That makes your 6 tpi screw act like a 4.235 tpi screw, which happens
to be 5.9972 mm per turn. That's close enough to 6mm to make good
fasteners. That will let you cut 11 common metric pitches with less
than 0.05% error (1 part per 2000). A smattering of other pitches can
be made with a few other gears, with slightly worse error. The usual
warning about leaving the half-nuts engaged applies with all of these,
BTW.

Gearbox, MM, %Err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

Also, you can pick up some of the other common screw threads if you
add a couple more gears to the mix:

If you replace the stud gear with a 43, the leadscrew will act like it
is 7.6mm, which does not sound useful. But with the ratios in the
gearbox, you can get the following:

Gearbox, MM, %Err
26 1.75 0.019
13 3.50 0.019

And, if you put the 24 tooth stud gear back, and instead replace the
64 tooth screw gear with a 50 tooth, you get the following:

Gearbox, MM, %Err
26 1.25 0.037
13 2.50 0.037

There are some other, finer common threads, but I doubt you will be
cutting them on an SB 13. If you have some other pitch you need, let
me know.

allan

On Sun, Oct 4, 2020 at 4:05 PM Rick <vwrick@optimum.net> wrote:

On Sun, Apr 23, 2017 at 10:04 AM, m. allan noah wrote:

Sure, assuming you have a double tumbler lathe, with a 8-224 range gearbox when the 24 tooth gear is installed, and which has a 64 tooth gear on the gearbox input, the following will work: replace the 24 tooth stud gear with a 34 tooth gear. This turns the gearbox 1.417 times its normal speed, so the leadscrew acts like it is 5.999mm pitch (6mm with 0.046% error). Then you can cut 11 metric threads as follows.

qcgb mmpt %err
144 0.25 0.046
80 0.45 0.046
72 0.50 0.046
48 0.75 0.046
40 0.90 0.046
36 1.00 0.046
24 1.50 0.046
18 2.00 0.046
12 3.00 0.046
9 4.00 0.046
8 4.50 0.046

If you lathe has a different gearbox, or other end gearing, or if you need some other thread than those listed, you would need some other gear. Let me know.

allan

Allan, does this apply to a double tumbler SB 13 also? If not, do you have a similar setup for the 13 double tumbler?

Thanks,

Rick


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"








--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"
--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"

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