Date   

Re: Metric Thread Dial

glenn brooks <brooks.glenn@...>
 




On Jan 3, 2021, at 9:20 AM, Davis Johnson <davis@...> wrote:

I don't think I have the right words to explain.

Too long, don't read warning....

The thread dial indicates the phase of the cutter with respect to a thread being cut.

With the half nuts unlocked moving the carriage or rotating the spindle changes the phase.

With the inch lead screw cutting inch threads the spindle the ratio between the spindle and the lead screw is simple. More importantly, you can lock the half nuts anywhere the appropriate mark lines up and be in sync with the thread you are cutting. About every 1/8th inch or so. I think. Need to check. In any event -- places you can lock the half nuts are separated by a fraction of a lead screw turn. HTRL has some notes on which marks you can use for which threads per inch (multiples of 2, 4 or 8tpi make a difference). The marks where you can engage the half nuts are the ones where the spindle has rotated back around to where you can pick up the thread.

Add the metric transposing gears, or one of the approximations, and the ratios get really messy. So messy that there is no simple, usable, relationship between the phase of the spindle and the thread dial indication. Spindle rotations don't divide evenly into lead screw rotations.

There are three solutions to cutting metric gears that I have heard of:

1) Don't disengage the half nuts while cutting threads. When done with a pass run the lathe backwards to return the carriage to make another pass. This is the most commonly suggested method. Somebody is sure to pipe up that they prefer doing this with inch threads even if they have a thread dial. This definitely works.

2) I have heard (but not tried) that starting with the carriage at the same position (perhaps using a carriage stop to the right of the carriage, or the tail stock as a carriage stop) AND always using the same mark on the dial (perhaps the 0 mark) will work. This makes sense to me mathematically - I won't bore you with the details)

3) I have also heard (but not tried) of a method where you turn off the lathe at the end of a pass, note the thread dial position, disengage the half nuts, move the carriage right to a position where the thread dial is the same as where it was when the half nuts were released and engage there. Then turn the lathe back on. I think there may be more to it than that -- it seems at least semi plausible to me.

The safe thing is to go with #1.

I'm amazed if anybody has managed to follow all of this. The math of this fascinates me, but if I start blathering about Stern-Brocot trees, prime factors, smooth numbers, least common multiples and largest common factors I'll deserve to be banned from this list.


On 1/3/21 10:56 AM, john kling via groups.io wrote:
Hm I don't feel particularly sharp today and have  not in the past thought about why the thread dial works - But would the imperial still coordinate the position of the carriage and the lead screw in metric operations on the imperial lathe. -if this is completely silly, ignore.

On Sunday, January 3, 2021, 10:08:19 AM EST, Steven H via groups.io <stevesmachining@...> wrote:


I have never heard of a metric thread dial. When cutting metric threads with an imperial lead screw lathe, one normally engages the half nuts and leave the half nuts engaged until you are done cutting the thread. Do not disengage the half nuts. Reverse the lathe to return the carriage to the starting point after backing out the cross slide. 

Steve Haskell
Troy, MI

On Jan 3, 2021, at 9:57 AM, Davis Johnson <davis@...> wrote:



The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Re: Metric Thread Dial

Davis Johnson
 

I don't think I have the right words to explain.

Too long, don't read warning....

The thread dial indicates the phase of the cutter with respect to a thread being cut.

With the half nuts unlocked moving the carriage or rotating the spindle changes the phase.

With the inch lead screw cutting inch threads the spindle the ratio between the spindle and the lead screw is simple. More importantly, you can lock the half nuts anywhere the appropriate mark lines up and be in sync with the thread you are cutting. About every 1/8th inch or so. I think. Need to check. In any event -- places you can lock the half nuts are separated by a fraction of a lead screw turn. HTRL has some notes on which marks you can use for which threads per inch (multiples of 2, 4 or 8tpi make a difference). The marks where you can engage the half nuts are the ones where the spindle has rotated back around to where you can pick up the thread.

Add the metric transposing gears, or one of the approximations, and the ratios get really messy. So messy that there is no simple, usable, relationship between the phase of the spindle and the thread dial indication. Spindle rotations don't divide evenly into lead screw rotations.

There are three solutions to cutting metric gears that I have heard of:

1) Don't disengage the half nuts while cutting threads. When done with a pass run the lathe backwards to return the carriage to make another pass. This is the most commonly suggested method. Somebody is sure to pipe up that they prefer doing this with inch threads even if they have a thread dial. This definitely works.

2) I have heard (but not tried) that starting with the carriage at the same position (perhaps using a carriage stop to the right of the carriage, or the tail stock as a carriage stop) AND always using the same mark on the dial (perhaps the 0 mark) will work. This makes sense to me mathematically - I won't bore you with the details)

3) I have also heard (but not tried) of a method where you turn off the lathe at the end of a pass, note the thread dial position, disengage the half nuts, move the carriage right to a position where the thread dial is the same as where it was when the half nuts were released and engage there. Then turn the lathe back on. I think there may be more to it than that -- it seems at least semi plausible to me.

The safe thing is to go with #1.

I'm amazed if anybody has managed to follow all of this. The math of this fascinates me, but if I start blathering about Stern-Brocot trees, prime factors, smooth numbers, least common multiples and largest common factors I'll deserve to be banned from this list.


On 1/3/21 10:56 AM, john kling via groups.io wrote:
Hm I don't feel particularly sharp today and have  not in the past thought about why the thread dial works - But would the imperial still coordinate the position of the carriage and the lead screw in metric operations on the imperial lathe. -if this is completely silly, ignore.

On Sunday, January 3, 2021, 10:08:19 AM EST, Steven H via groups.io <stevesmachining@...> wrote:


I have never heard of a metric thread dial. When cutting metric threads with an imperial lead screw lathe, one normally engages the half nuts and leave the half nuts engaged until you are done cutting the thread. Do not disengage the half nuts. Reverse the lathe to return the carriage to the starting point after backing out the cross slide. 

Steve Haskell
Troy, MI

On Jan 3, 2021, at 9:57 AM, Davis Johnson <davis@...> wrote:



The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Re: Metric Thread Dial

Bill in OKC too
 

Disclaimer: I have never cut an English thread on a metric machine or vice versa, but with the metric change gears it seems to me that it SHOULD work. When I say things like that SWMBO says I'm "shoulding all over myself." ;) Anyone who knows better, feel free to school me. In the mean time, I would suggest trying it, and seeing. I hope to be finding out for myself, one of these days soon. I have an HF mini-lathe for which I still need to print a 100-tooth gear to go with the 127-tooth gear I already have. The lead screw on mine is 16tpi. I've also got a single-tumbler SB Heavy 10L that I hope to be able to add metric transposition gears to once I finish the restoration project. I seem to recall reading that it's not quite so straight forward on the single tumbler gearbox machines, but if I can print a gear for it, it won't be too expensive to try. 

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 Sunday, January 3, 2021, 09:56:36 AM CST, john kling via groups.io <jkling222@...> wrote:


Hm I don't feel particularly sharp today and have  not in the past thought about why the thread dial works - But would the imperial still coordinate the position of the carriage and the lead screw in metric operations on the imperial lathe. -if this is completely silly, ignore.

On Sunday, January 3, 2021, 10:08:19 AM EST, Steven H via groups.io <stevesmachining@...> wrote:


I have never heard of a metric thread dial. When cutting metric threads with an imperial lead screw lathe, one normally engages the half nuts and leave the half nuts engaged until you are done cutting the thread. Do not disengage the half nuts. Reverse the lathe to return the carriage to the starting point after backing out the cross slide. 

Steve Haskell
Troy, MI

On Jan 3, 2021, at 9:57 AM, Davis Johnson <davis@...> wrote:



The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Metric thread dial

Jim_B
 


There are metric thread dials. As noted they are for metric threaded lead screws. Also they are quite complex and have multiple gears depending on the thread pitch.








Sent from my iPhone-8 no
Jim B,

--
Jim B


Re: Metric Thread Dial

joel wahl
 

sadly, there is not metric thread dial, the lead screw is Imperial (8 tpi, if i remember correctly).....the numbers just won't work out....the lead screw would need to be metric for a thread dial to work on it...... for metric threads you would need to never dis-engage half-nut.


Re: Metric Thread Dial

john kling
 

Hm I don't feel particularly sharp today and have  not in the past thought about why the thread dial works - But would the imperial still coordinate the position of the carriage and the lead screw in metric operations on the imperial lathe. -if this is completely silly, ignore.

On Sunday, January 3, 2021, 10:08:19 AM EST, Steven H via groups.io <stevesmachining@...> wrote:


I have never heard of a metric thread dial. When cutting metric threads with an imperial lead screw lathe, one normally engages the half nuts and leave the half nuts engaged until you are done cutting the thread. Do not disengage the half nuts. Reverse the lathe to return the carriage to the starting point after backing out the cross slide. 

Steve Haskell
Troy, MI

On Jan 3, 2021, at 9:57 AM, Davis Johnson <davis@...> wrote:



The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Re: Metric Thread Dial

Steven H
 

I have never heard of a metric thread dial. When cutting metric threads with an imperial lead screw lathe, one normally engages the half nuts and leave the half nuts engaged until you are done cutting the thread. Do not disengage the half nuts. Reverse the lathe to return the carriage to the starting point after backing out the cross slide. 

Steve Haskell
Troy, MI

On Jan 3, 2021, at 9:57 AM, Davis Johnson <davis@...> wrote:



The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Re: Metric Thread Dial

Davis Johnson
 

The metric thread dial is intended for use with a metric lead screw, not transposing gears.

Conventional wisdom is that the normal threading dial is not useful with the transposing gears, no doubt why you are interested in the metric thread dial.

I have read a contrary opinion, that it will work if you reposition the carriage the same place for every pass (perhaps a carriage stop to the right of the carriage? might have to go on the rear v-way.) AND start on the same dial mark each time. It sounds reasonable to me.

I have been wanting to try this for some time, but haven't done it yet. Next best thing for me would be for you to try it.

On 1/3/21 8:58 AM, Al Costich wrote:
For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


Metric Thread Dial

Al Costich
 

For some silly reason, I am in the hunt for a metric thread dial for a 9A.
Some time ago I acquired a 127/100 transposing gear set and some additional
gears.
Thinking forward, i would like to single point some metric bolts.
I'm not confident enough to make a thread dial myself.
So, should anyone have one that is superfluous to their needs,
contact me.

Thanks.

Alan


For sale: 1949 9A in near-original condition with many original accessories

Jim Schwitters
 

I'm the second owner of this lathe originally delivered to the US Army at Camp Lee in Dec 1949 (per SB's serial number card).  I confirmed its working condition then disassembled it to major components for storage intending it for a grandson.  For sale in central South Carolina.  $2250 plus shipping.  I will palletize and crate in a manner fitting its uniqueness and deliver to a local shipper that you arrange.
Pictures here:  https://groups.io/g/SouthBendLathe/album?id=258628  4 ft bed with all the attachments and accessories shown.  Major items include: taper attachment; steady rest; follow rest; manual collet drawbar and sleeve with 8 #3 collets (1/16 to 1/2") in original SB containers; collet rack; threading dial; milling attachment; micrometer carriage stop; threading stop; 3MT milling arbor; 8" faceplate; 5' SB/Cushman 3 jaw chuck with both jaw sets; 6" SB/Skinner 4 jaw chuck; Jacobs 58B spindle chuck; 2MT tailstock chuck, various rocker tool holders; several turning dogs and various original wrenches.  Also includes photo copy of original serial number card and original oiling and bench mounting prints.
The lathe bed is virtually unworn with no discernible ridge on the inverted Vee.  Almost no rust on anything; exceptions are several spots on the taper slide and a portion of the 6" chuck.  No signs of abuse though there are a couple minor marks of shame on the compound.  The motor does not run when plugged in but I have not checked it out.  Everything is in original paint.  Additional photos and details on request.
Jim   jrschwit@...


Re: Will a 9-A leadscrew work for a 9-C to 9-B conversion (no quickchange)?

Stuart Wilby <stuartawilby@...>
 

Thank you, however, McMaster Carr do not supply to the UK, there is no franchise visible for their catalogue of components, maybe after leaving the EU the WTO will allow a better tariff and reasonable shipping, this company would do well in the UK, we are a resourceful nation, we invent things, we repair things, we need you here, we have suppliers who are first rate, ie, simply bearings, but not on the scale of the aforementioned in the USA.


Re: Old 11" for sale.

Steve Wells
 

Thank you for the serial Numbers and info, I appreciate it greatly.
His lathe was shipped in 1927

All the best,
Steve Wells
The SBL Workshop
www.wswells.com
 

From: Todd
Sent: Wednesday, November 18, 2020 9:40 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Old 11" for sale.
 
My buddy has an old 11" for sale. Been sitting in his barn for a few years. No legs as he repurposed them but the rest is there.  Cat 333-Y, serial 36232.  3' bed.  No motor, no chuck, no extra change gears & only has a faceplate. 
He's asking $300. 


Re: tune up

Bill in OKC too
 

Depends on what you mean by "tuning up." If you're trying to get a lathe running that has been out of service for some time, the books from Illion Press are great. I've got a Heavy 10L, vintage 1941, and the book for it (with a kit of replacement wicks for the oiling system) is under $90, depending on where you get it. Ebay has a better price, Amazon maybe ships a little quicker. https://www.amazon.com/gp/product/B01K58YD2W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Search on the model you have, and they probably have the book, which I found invaluable! Mine isn't completely restored, but I've not broken anything following their instructions, either. ;)

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 Monday, December 21, 2020, 11:29:33 AM CST, Fred Flintstone via groups.io <stoeger666@...> wrote:


Happy holidays all,

What is the best book/video on tuning up my lathe?

Does anyone know the best for tuning up my bridgeport?

Take care,
Mark


Re: tune up

Steven H
 

Regarding your lathe, go to the Files section of the Group. There is a file name TechInfo that has information on adjusting the backgears and checking and adjusting the spindle bearings. Should be some info on ‘leveling’ your lathe also somewhere in the files. 

Steve Haskell
Troy, MI

On Dec 21, 2020, at 12:29 PM, Fred Flintstone via groups.io <stoeger666@...> wrote:


Happy holidays all,

What is the best book/video on tuning up my lathe?

Does anyone know the best for tuning up my bridgeport?

Take care,
Mark


tune up

Fred Flintstone
 

Happy holidays all,

What is the best book/video on tuning up my lathe?

Does anyone know the best for tuning up my bridgeport?

Take care,
Mark


Re: Southbend 15 lathe

bob
 

I've had people come up from Texas and New York though so this wouldn't be much more than a day trip.


Re: Southbend 15 lathe

bob
 

The lead screw is a couple of feet too long so it would have to be cut and the end machined but it is way too long to ship so it would have to be picked up. I'm about 50 miles south of Chicago.


Re: Southbend 15 lathe

Todd
 

Someone posted yesterday looking for a leadscrew and gearbox for a 15"   sounds like your 1st sale

Sent from my Verizon, Samsung Galaxy smartphone


From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of Sam <i.am.sam.sam.i.am2008@...>
Sent: Sunday, December 20, 2020 2:38:26 AM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Southbend 15 lathe
 
If it was working before you tore it apart, it's too late for you- but for others consider this

It would be a completely useful lathe in a welding shop, no worries to keep it pristine, perfect for weld prep on pipe, or as a huge weld positioner for spray welding up bearing surfaces, or worn journals, or all the other ways they could abuse it.

Plus when you go to sell it, just one phone call, one buyer, one ad.

parting out some old machine with few others looking for those parts - not that much demand + way too many phone calls and such.

On Sat, Dec 19, 2020 at 9:19 PM Daniel Naunton <Dannaunton@...> wrote:
Thanks Bob. Let me know when you guys are back. Cheers

Daniel Naunton


402 871 6855



From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of bob <atwatterkent@...>
Sent: Saturday, December 19, 2020 8:15:54 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Southbend 15 lathe
 
This 15" SB is being scrapped. I have completely disassembled it. It was in good working order in our shop but the bed had been badly abused by a previous owner. I was able to thread and machine parts to close tolerance on it. Our shop is closed until Jan 8 and the pieces will not be available until then if you can wait that long.


Re: Southbend 15 lathe

Sam
 

If it was working before you tore it apart, it's too late for you- but for others consider this

It would be a completely useful lathe in a welding shop, no worries to keep it pristine, perfect for weld prep on pipe, or as a huge weld positioner for spray welding up bearing surfaces, or worn journals, or all the other ways they could abuse it.

Plus when you go to sell it, just one phone call, one buyer, one ad.

parting out some old machine with few others looking for those parts - not that much demand + way too many phone calls and such.


On Sat, Dec 19, 2020 at 9:19 PM Daniel Naunton <Dannaunton@...> wrote:
Thanks Bob. Let me know when you guys are back. Cheers

Daniel Naunton


402 871 6855



From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of bob <atwatterkent@...>
Sent: Saturday, December 19, 2020 8:15:54 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Southbend 15 lathe
 
This 15" SB is being scrapped. I have completely disassembled it. It was in good working order in our shop but the bed had been badly abused by a previous owner. I was able to thread and machine parts to close tolerance on it. Our shop is closed until Jan 8 and the pieces will not be available until then if you can wait that long.


Re: Southbend 15 lathe

Daniel Naunton
 

Thanks Bob. Let me know when you guys are back. Cheers

Daniel Naunton


402 871 6855



From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of bob <atwatterkent@...>
Sent: Saturday, December 19, 2020 8:15:54 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Southbend 15 lathe
 
This 15" SB is being scrapped. I have completely disassembled it. It was in good working order in our shop but the bed had been badly abused by a previous owner. I was able to thread and machine parts to close tolerance on it. Our shop is closed until Jan 8 and the pieces will not be available until then if you can wait that long.

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