Date   

Re: TPI discrepancy

m. allan noah
 

The leadscrew is 8 too, not 9. The gearbox input gear is 56 tooth, not 40.


On Sun, Jul 26, 2020, 5:42 PM John Dammeyer <johnd@...> wrote:

Threading isn't rocket science.  To me the 9 TPI leadscrew doesn't sound right but I don't know.  Maybe South Bends did come with that.

 

I'd put a dial indicator on the ways and then turn the lead screw by hand one turn with the half nut engaged and the backlash removed by first turning the leadscrew a few turns in the same direction.  If it's 8 TPI it would 0.125". If it's 9 TPI it's 0.11111111111111111111111…" which is not really logical.  Where if 10 TPI it's 0.1  Generally leadscrews are set up to not have infinite repeating decimals.

 

Next forget about the pitch you want and if the leadscrew is really 9 TPI then set up to cut 9 TPI.  Now the lead screw will turn exactly one turn for each turn of the spindle.  If that doesn't work again take a look at the gears.

 

John Dammeyer

 

"ELS! Nothing else works as well for your Lathe"

Automation Artisans Inc.

www dot autoartisans dot com

 

 

 

 

 

From: SouthBendLathe@groups.io [mailto:SouthBendLathe@groups.io] On Behalf Of Michael R via groups.io
Sent: July-26-20 2:31 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] TPI discrepancy

 

Yep, using the half nuts for threading.

The gear configuration is as follows:
Top stud gear - 40t (according to my parts manual it should be 20t)
Idler gear - 80t
Stud gear to lead screw - 40t (this is correct as it's indicated on the gearbox thread chart)
Lead screw - 9p

Another issue with this machine is that the longitudinal power feed spins way too fast, not delivering a good finish.

Wondering if the top stud gear could be the culprit for both problems?


Re: TPI discrepancy

John Dammeyer
 

Threading isn't rocket science.  To me the 9 TPI leadscrew doesn't sound right but I don't know.  Maybe South Bends did come with that.

 

I'd put a dial indicator on the ways and then turn the lead screw by hand one turn with the half nut engaged and the backlash removed by first turning the leadscrew a few turns in the same direction.  If it's 8 TPI it would 0.125". If it's 9 TPI it's 0.11111111111111111111111…" which is not really logical.  Where if 10 TPI it's 0.1  Generally leadscrews are set up to not have infinite repeating decimals.

 

Next forget about the pitch you want and if the leadscrew is really 9 TPI then set up to cut 9 TPI.  Now the lead screw will turn exactly one turn for each turn of the spindle.  If that doesn't work again take a look at the gears.

 

John Dammeyer

 

"ELS! Nothing else works as well for your Lathe"

Automation Artisans Inc.

www dot autoartisans dot com

 

 

 

 

 

From: SouthBendLathe@groups.io [mailto:SouthBendLathe@groups.io] On Behalf Of Michael R via groups.io
Sent: July-26-20 2:31 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] TPI discrepancy

 

Yep, using the half nuts for threading.

The gear configuration is as follows:
Top stud gear - 40t (according to my parts manual it should be 20t)
Idler gear - 80t
Stud gear to lead screw - 40t (this is correct as it's indicated on the gearbox thread chart)
Lead screw - 9p

Another issue with this machine is that the longitudinal power feed spins way too fast, not delivering a good finish.

Wondering if the top stud gear could be the culprit for both problems?


Re: TPI discrepancy

Michael R
 

Yep, using the half nuts for threading.

The gear configuration is as follows:
Top stud gear - 40t (according to my parts manual it should be 20t)
Idler gear - 80t
Stud gear to lead screw - 40t (this is correct as it's indicated on the gearbox thread chart)
Lead screw - 9p

Another issue with this machine is that the longitudinal power feed spins way too fast, not delivering a good finish.

Wondering if the top stud gear could be the culprit for both problems?


Re: TPI discrepancy

glenn brooks
 

Hmmm,  you can always cut a test thread and measure the actual pitch with a known gauge.


On Jul 26, 2020, at 12:07 PM, eddie.draper@... via groups.io <eddie.draper@...> wrote:


Oh dear!

Has whoever sold you the lathe kindly supplied a metric transposing gear (127 teeth) in the train under the cover on the left hand side?  Check the tooth counts for all the gears from spindle to gearbox input and see if they match what is in the catalogue.  There might be a listing somewhere in the files section.

I take it your leadscrew has an Imperial rather than metric pitch?  Worth a check.

Eddie

On Sunday, 26 July 2020, 19:46:42 BST, Michael R via groups.io <reflexermr@...> wrote:


I'm threading a backplate for the Jacobs collet chuck. The spindle is 8 tpi. I've checked that the gearbox levers are in the correct position and
did the obligatory scratch pass. The gage shows it closer to a 7 tpi than 8. Any thought as to what would cause this discrepancy?

This is the first time single pointing with this lathe.
Thanks,
Michael


Re: TPI discrepancy

eddie.draper@btinternet.com
 

Oh dear!

Has whoever sold you the lathe kindly supplied a metric transposing gear (127 teeth) in the train under the cover on the left hand side?  Check the tooth counts for all the gears from spindle to gearbox input and see if they match what is in the catalogue.  There might be a listing somewhere in the files section.

I take it your leadscrew has an Imperial rather than metric pitch?  Worth a check.

Eddie

On Sunday, 26 July 2020, 19:46:42 BST, Michael R via groups.io <reflexermr@...> wrote:


I'm threading a backplate for the Jacobs collet chuck. The spindle is 8 tpi. I've checked that the gearbox levers are in the correct position and
did the obligatory scratch pass. The gage shows it closer to a 7 tpi than 8. Any thought as to what would cause this discrepancy?

This is the first time single pointing with this lathe.
Thanks,
Michael


Re: TPI discrepancy

comstock_friend
 
Edited

Correct end gears in the gear train? Using half nuts and not the feed knob/lever?

John


Re: South Bend Model "N" Owners - Resources

comstock_friend
 

Dennis Turk has been playing over on Facebook

John


TPI discrepancy

Michael R
 

I'm threading a backplate for the Jacobs collet chuck. The spindle is 8 tpi. I've checked that the gearbox levers are in the correct position and
did the obligatory scratch pass. The gage shows it closer to a 7 tpi than 8. Any thought as to what would cause this discrepancy?

This is the first time single pointing with this lathe.
Thanks,
Michael


9" series o

Roger Bickers
 

ive got a 9" Series O (wide bed) that im going to part with. Itll need a compound (a bare one will work), it'll need the gear for the crossfeeds (I used it on another lathe (that lathe was sold)), itll also need a couple of gears in the apron. Ironically all the other apron gears look good, I figured someone took it apart to clean and either lost them, or died before it was put back together and they got lost that way.  The bed looks pretty good. No issues with the headstock or tailstock. Headstock gears and reversing lever n gears are in great shape. 
$450.00 

Roger


Re: South Bend Model "N" Owners - Resources

david_g4000
 

Animal,

There is some interesting history being posted in this thread. To summarize some of it - It was a short production period for this higher priced model, due to the economic times of the 1930's. The N was a high precision "tool room" class lathe with a heavy headstock construction and wide ways, among other features, that increased the cost to produce. Also, the double tumbler feature came along in subsequent models. Some of the controls are rather unique as well. Also, the apron design. I am enjoying the contributions from many on this topic.

Dave

On 7/25/2020 7:49 PM, mike allen wrote:
yea , I'm interested in learnin what the difference is between a type N & the other lathes

��� ��� animal

On 7/25/2020 7:57 AM, m. allan noah wrote:
I've never used a Series N power feeds- how is it that the leadscrew
reverse tumbler direction controls facing vs turning?

allan

On Sat, Jul 25, 2020 at 10:52 AM david_g4000 via groups.io
<dmbanwarth=verizon.net@groups.io> wrote:
That was the problem I was having too. Glad it is helpful Dan. If you see any updates needed, please let me know.

-------- Original message --------
From: Dan Beeker <debeeker@indiana.edu>
Date: 7/25/20 10:21 AM (GMT-05:00)
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] South Bend Model "N" Owners - Resources

What a great resource. I use my 16�� Type N South Bend just often enough to forget how to switch between turning and threading. Your documents will fill a sacred spot on the wall beside my lathe. Thank you for posting the instructions.



Dan Beeker



PureUnobtanium.com

Indiana University - retired





Re: South Bend Model "N" Owners - Resources

Bill in OKC too
 

Good to hear. If you remember, tell him Bill Meyers from the old Yahoo Metal Shapers group said "Hello!"

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Saturday, July 25, 2020, 09:55:48 PM CDT, karlw144 via groups.io <karlw144@...> wrote:


Dennis is a good friend of mine and he is doing well. He’s as busy as ever restoring machines and building models. 


Re: South Bend Model "N" Owners - Resources

karlw144
 

Dennis is a good friend of mine and he is doing well. He’s as busy as ever restoring machines and building models. 


Re: South Bend Model "N" Owners - Resources

david_g4000
 

Thanks very much.

Dave

On 7/25/2020 8:09 PM, Jim_B wrote:
We used to have a member, Dennis Turk, who was a wealth of information on S B history. Here is some wisdom from him.



You can find an ???N??? catalog on Steve Wells site.
www.wswells.com.

Sent from my iPhone-8
Jim B,

On Jul 25, 2020, at 7:50 PM, mike allen <animal@psln.com> wrote:

??? yea , I'm interested in learnin what the difference is between a type N & the other lathes

animal

On 7/25/2020 7:57 AM, m. allan noah wrote:
I've never used a Series N power feeds- how is it that the leadscrew
reverse tumbler direction controls facing vs turning?

allan

On Sat, Jul 25, 2020 at 10:52 AM david_g4000 via groups.io
<dmbanwarth=verizon.net@groups.io> wrote:
That was the problem I was having too. Glad it is helpful Dan. If you see any updates needed, please let me know.

-------- Original message --------
From: Dan Beeker <debeeker@indiana.edu>
Date: 7/25/20 10:21 AM (GMT-05:00)
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] South Bend Model "N" Owners - Resources

What a great resource. I use my 16??? Type N South Bend just often enough to forget how to switch between turning and threading. Your documents will fill a sacred spot on the wall beside my lathe. Thank you for posting the instructions.



Dan Beeker



PureUnobtanium.com

Indiana University - retired





Re: South Bend Model "N" Owners - Resources

Bill in OKC too
 

Dennis was a great resource. I've not heard anything from him in a while now. Hope he's OK. Steve Well's site is also a great resource! I've got some of Dennis's info on metal shapers in the messages at my metal shapers group. Some of his info is still here in the messages, too. And his company website is still up, so he may just be busy. I hope. 

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Saturday, July 25, 2020, 07:09:35 PM CDT, Jim_B <jim@...> wrote:


We used to have a member, Dennis Turk, who was a wealth of information on S B history. Here is some wisdom from him.



You can find an “N� catalog on Steve Wells site.
www.wswells.com.

-8
Jim B,

> On Jul 25, 2020, at 7:50 PM, mike allen <animal@...> wrote:
>
>         yea , I'm interested in learnin what the difference is between a type N & the other lathes
>
>        animal
>
>> On 7/25/2020 7:57 AM, m. allan noah wrote:
>> I've never used a Series N power feeds- how is it that the leadscrew
>> reverse tumbler direction controls facing vs turning?
>>
>> allan
>>
>>> On Sat, Jul 25, 2020 at 10:52 AM david_g4000 via groups.io
>>> <dmbanwarth=verizon.net@groups.io> wrote:
>>> That was the problem I was having too. Glad it is helpful Dan. If you see any updates needed, please let me know.
>>>
>>> -------- Original message --------
>>> From: Dan Beeker <debeeker@...>
>>> Date: 7/25/20 10:21 AM (GMT-05:00)
>>> To: SouthBendLathe@groups.io
>>> Subject: Re: [SouthBendLathe] South Bend Model "N" Owners - Resources
>>>
>>> What a great resource. I use my 16â€�  Type N South Bend just often enough to forget how to switch between turning and threading. Your documents will fill a sacred spot on the wall beside my lathe. Thank you for posting the instructions.
>>>
>>>
>>>
>>> Dan Beeker
>>>
>>>
>>>
>>> PureUnobtanium.com
>>>
>>> Indiana University - retired
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>


--
Jim B



Re: South Bend Model "N" Owners - Resources

Jim_B
 

We used to have a member, Dennis Turk, who was a wealth of information on S B history. Here is some wisdom from him.



You can find an “N” catalog on Steve Wells site.
www.wswells.com.

Sent from my iPhone-8
Jim B,

On Jul 25, 2020, at 7:50 PM, mike allen <animal@psln.com> wrote:

 yea , I'm interested in learnin what the difference is between a type N & the other lathes

animal

On 7/25/2020 7:57 AM, m. allan noah wrote:
I've never used a Series N power feeds- how is it that the leadscrew
reverse tumbler direction controls facing vs turning?

allan

On Sat, Jul 25, 2020 at 10:52 AM david_g4000 via groups.io
<dmbanwarth=verizon.net@groups.io> wrote:
That was the problem I was having too. Glad it is helpful Dan. If you see any updates needed, please let me know.

-------- Original message --------
From: Dan Beeker <debeeker@indiana.edu>
Date: 7/25/20 10:21 AM (GMT-05:00)
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] South Bend Model "N" Owners - Resources

What a great resource. I use my 16” Type N South Bend just often enough to forget how to switch between turning and threading. Your documents will fill a sacred spot on the wall beside my lathe. Thank you for posting the instructions.



Dan Beeker



PureUnobtanium.com

Indiana University - retired





--
Jim B


Re: South Bend Model "N" Owners - Resources

mike allen
 

yea , I'm interested in learnin what the difference is between a type N & the other lathes

        animal

On 7/25/2020 7:57 AM, m. allan noah wrote:
I've never used a Series N power feeds- how is it that the leadscrew
reverse tumbler direction controls facing vs turning?

allan

On Sat, Jul 25, 2020 at 10:52 AM david_g4000 via groups.io
<dmbanwarth=verizon.net@groups.io> wrote:
That was the problem I was having too. Glad it is helpful Dan. If you see any updates needed, please let me know.

-------- Original message --------
From: Dan Beeker <debeeker@indiana.edu>
Date: 7/25/20 10:21 AM (GMT-05:00)
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] South Bend Model "N" Owners - Resources

What a great resource. I use my 16” Type N South Bend just often enough to forget how to switch between turning and threading. Your documents will fill a sacred spot on the wall beside my lathe. Thank you for posting the instructions.



Dan Beeker



PureUnobtanium.com

Indiana University - retired




Re: South Bend Model "N" Owners - Resources

david_g4000
 
Edited

Eddie,

Thanks for the comments. You are doing a lot more thread types than I normally do. You are correct that it could be misleading, as I normally only do UNC or UNF threading on this lathe.

I normally use a HSS ground tool or a BXA mounted preformed tool for threading, but recently got a formed carbide threading insert tool to try out.

Thanks again, very helpful.

Dave

On 7/25/2020 3:55 PM, eddie.draper@... via groups.io wrote:
Just 2 minor comments:
 
Not all threads have a 60 degree angle (the instruction says to set the compund at 30 degrees).� That applies only so far as I know to American UN form and ISO metric form.� Whitworth form threads are 55 degrees, so set the compound at 27.5 degrees.� Acme is 29 degrees, so set to 14.5 degrees, Metric trapezoidal threads (ISO equivalent to Acme) are 30 degrees, so set to 15.� You are unlikely to want to screwcut BA threads (47.5 degrees) as all the thread pitches apart from 0BA (1mm pitch) are difficult to achieve as they and the diameters proceed in a geometric progression, not in nice round numbers in anybody's system.
 
Setting the compound over at half the thread angle applies only to cutting tools that are not manufactured full form carbide inserts.� Single purpose full form carbide threading inserts go straight in.�
 
If making a general purpose 55 or 60 degree angle tool for use with feed from the compound slide, only one side will do most or all of the cutting, so the top rake should be a.) suited to the workpiece material and b.) parallel to the direction of feed.
 
Actually, when cutting ACME or the ISO equivalent, I keep the compound set at 0, so upon achieving the correct measured major & minor diameters and finding the mating thread still tight, I can advance the tool a thour or two at a time longitudinally to widen the groove until it suddenly frees off when tried.� I would do the same if I ever had to cut a square thread.
 
Best wishes to all, and stay healthy,
 
Eddie
 
On Saturday, 25 July 2020, 19:07:12 BST, Louis via groups.io <l_schoolkate@...> wrote:
 
 
Everything in your write-up looks fine to me.
I too have a model 'N' but a smaller 9x34 dating to roughly 1933. I've owned mine now for 4 years and it's my go-to lathe for smaller work.�

My 9" has a heavier built headstock compared to other 9" South Bends of the same era. The bed is also wider and has the same cross section as my ~1944 Heavy 10. It also has the similar heavy double walled apron and the cross feed and compound both have adjustable tapered gibs. My research indicates that Model 'N's were the more expensive commercial line lathes. During the Great Depression South Bend cut out some of those more expensive features to reduce the cost in some of their other lines.

My 9" sat unused for many decades and shows little wear. Although the controls are slightly different, in practice they work similar to the Heavy 10. Given how overbuilt it is, I expect it will outlive me by many years.

Just for interest's sake, my Heavy 10 is also an unusual model, a Series 'S' benchtop model. It's labelled as a 10L 487Z and has the large bore spindle. However, it has the typical SB rear countershaft not an undermount drive. The lathe is illustrated in the 1941 South Bend catalog on page 41 along with the 487Z catalog number.�


Re: South Bend Model "N" Owners - Resources

eddie.draper@btinternet.com
 

Just 2 minor comments:

Not all threads have a 60 degree angle (the instruction says to set the compund at 30 degrees).  That applies only so far as I know to American UN form and ISO metric form.  Whitworth form threads are 55 degrees, so set the compound at 27.5 degrees.  Acme is 29 degrees, so set to 14.5 degrees, Metric trapezoidal threads (ISO equivalent to Acme) are 30 degrees, so set to 15.  You are unlikely to want to screwcut BA threads (47.5 degrees) as all the thread pitches apart from 0BA (1mm pitch) are difficult to achieve as they and the diameters proceed in a geometric progression, not in nice round numbers in anybody's system.

Setting the compound over at half the thread angle applies only to cutting tools that are not manufactured full form carbide inserts.  Single purpose full form carbide threading inserts go straight in. 

If making a general purpose 55 or 60 degree angle tool for use with feed from the compound slide, only one side will do most or all of the cutting, so the top rake should be a.) suited to the workpiece material and b.) parallel to the direction of feed.

Actually, when cutting ACME or the ISO equivalent, I keep the compound set at 0, so upon achieving the correct measured major & minor diameters and finding the mating thread still tight, I can advance the tool a thour or two at a time longitudinally to widen the groove until it suddenly frees off when tried.  I would do the same if I ever had to cut a square thread.

Best wishes to all, and stay healthy,

Eddie

On Saturday, 25 July 2020, 19:07:12 BST, Louis via groups.io <l_schoolkate@...> wrote:


Everything in your write-up looks fine to me.
I too have a model 'N' but a smaller 9x34 dating to roughly 1933. I've owned mine now for 4 years and it's my go-to lathe for smaller work. 

My 9" has a heavier built headstock compared to other 9" South Bends of the same era. The bed is also wider and has the same cross section as my ~1944 Heavy 10. It also has the similar heavy double walled apron and the cross feed and compound both have adjustable tapered gibs. My research indicates that Model 'N's were the more expensive commercial line lathes. During the Great Depression South Bend cut out some of those more expensive features to reduce the cost in some of their other lines.

My 9" sat unused for many decades and shows little wear. Although the controls are slightly different, in practice they work similar to the Heavy 10. Given how overbuilt it is, I expect it will outlive me by many years.

Just for interest's sake, my Heavy 10 is also an unusual model, a Series 'S' benchtop model. It's labelled as a 10L 487Z and has the large bore spindle. However, it has the typical SB rear countershaft not an undermount drive. The lathe is illustrated in the 1941 South Bend catalog on page 41 along with the 487Z catalog number. 


Re: South Bend Model "N" Owners - Resources

david_g4000
 

Louis,

Thanks for the feedback, and I really enjoy learning more history of the N series and the comparisons you pointed out. Mine is a 1931 which was delivered to a utility company machine shop where it seems to have seen limited use as well. Someone at the shop let me know that it was going to be surplussed and that it had not been run for at least 30 years. So, it is in great condition as well. I recently modified it to upgrade from 3/4hp to 1.5hp, 3 Phase. The old motor needed re-winding and the cost was too much. It's nice that the new motor has lifetime lubrication, which I'm sure will outlive me as well.

It wish I had a larger spindle bore sometimes like your Heavy 10. But, I can dog drive larger work pieces between centers if needed.

I will take a look at the Series S.

Thanks,

Dave

On 7/25/2020 2:07 PM, Louis via groups.io wrote:
Everything in your write-up looks fine to me.
I too have a model 'N' but a smaller 9x34 dating to roughly 1933. I've owned mine now for 4 years and it's my go-to lathe for smaller work.?

My 9" has a heavier built headstock compared to other 9" South Bends of the same era. The bed is also wider and has the same cross section as my ~1944 Heavy 10. It also has the similar heavy double walled apron and the cross feed and compound both have adjustable tapered gibs. My research indicates that Model 'N's were the more expensive commercial line lathes. During the Great Depression South Bend cut out some of those more expensive features to reduce the cost in some of their other lines.

My 9" sat unused for many decades and shows little wear. Although the controls are slightly different, in practice they work similar to the Heavy 10. Given how overbuilt it is, I expect it will outlive me by many years.

Just for interest's sake, my Heavy 10 is also an unusual model, a Series 'S' benchtop model. It's labelled as a 10L 487Z and has the large bore spindle. However, it has the typical SB rear countershaft not an undermount drive. The lathe is illustrated in the 1941 South Bend catalog on page 41 along with the 487Z catalog number.?


Re: South Bend Model "N" Owners - Resources

Louis
 

Everything in your write-up looks fine to me.
I too have a model 'N' but a smaller 9x34 dating to roughly 1933. I've owned mine now for 4 years and it's my go-to lathe for smaller work. 

My 9" has a heavier built headstock compared to other 9" South Bends of the same era. The bed is also wider and has the same cross section as my ~1944 Heavy 10. It also has the similar heavy double walled apron and the cross feed and compound both have adjustable tapered gibs. My research indicates that Model 'N's were the more expensive commercial line lathes. During the Great Depression South Bend cut out some of those more expensive features to reduce the cost in some of their other lines.

My 9" sat unused for many decades and shows little wear. Although the controls are slightly different, in practice they work similar to the Heavy 10. Given how overbuilt it is, I expect it will outlive me by many years.

Just for interest's sake, my Heavy 10 is also an unusual model, a Series 'S' benchtop model. It's labelled as a 10L 487Z and has the large bore spindle. However, it has the typical SB rear countershaft not an undermount drive. The lathe is illustrated in the 1941 South Bend catalog on page 41 along with the 487Z catalog number. 

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