cut an M1.75 thread


Jack Dinan
 

I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?


Glenn N
 

Here is the info I have from a different source
M1.75
Stud gear 28
Screw gear 56
Plunger whole B
Plunger hole 1
Gear 1 127/100

I hope this is helpful.

Glenn

On Sep 15, 2021, at 2:51 PM, Jack Dinan <jack@thedinans.net> wrote:

I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?







Jack Dinan
 

Glen: I have that same combination from an internet source.
Since I don’t happen to have a 28 tooth gear, I was hoping that the SB manual was correct.
Strange.

On Sep 15, 2021, at 2:58 PM, Gl NO <glenngnorris@gmail.com> wrote:

Here is the info I have from a different source
M1.75
Stud gear 28
Screw gear 56
Plunger whole B
Plunger hole 1
Gear 1 127/100

I hope this is helpful.

Glenn
On Sep 15, 2021, at 2:51 PM, Jack Dinan <jack@thedinans.net> wrote:

I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?










Davis Johnson
 

Note that 28 is half of 56. You can double or halve either stud or screw gear and move one row on the chart.

That means you can run 56 on both stud and screw and move down to the C hole and get the same ratio. Since every lathe came with a 56 tooth gear they are reasonably plentiful on eBay.

You can also change to any stud and screw gears that give you the same ratio and stay in the same holes. 56:56 is 1:1 - so any two identical gears on stud and screw will work in holes C-1.

That means 40:40 will work in C:1.

Applying the "double or halve move one row" rule you can go to a 20 tooth stud gear and a 40 tooth screw gear and move back to hole B-1. You could have gotten here directly from 28:56 by the same ratio rule but I wanted to show that there were lots of combinations.

The great thing about 20:40 is that both of these came standard with the lathe, although the 40 tooth gear sometimes gets lost.

On 9/15/21 2:58 PM, Gl NO wrote:
Here is the info I have from a different source
M1.75
Stud gear 28
Screw gear 56
Plunger whole B
Plunger hole 1
Gear 1 127/100

I hope this is helpful.

Glenn
On Sep 15, 2021, at 2:51 PM, Jack Dinan <jack@thedinans.net> wrote:

I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?








m. allan noah
 

Did you buy a 120/100, or a 127/100?

allan


On Wed, Sep 15, 2021 at 2:51 PM Jack Dinan <jack@...> wrote:
I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?









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


Jack Dinan
 

Allan:  whoops. 

Make that 127/100.

Thanks for that.
jack

On Sep 16, 2021, at 7:39 AM, m. allan noah <kitno455@...> wrote:

Did you buy a 120/100, or a 127/100?

allan

On Wed, Sep 15, 2021 at 2:51 PM Jack Dinan <jack@...> wrote:
I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?









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


Jack Dinan
 

Davis: I’m grateful for this lucid explanation.

Just what I need to proceed.

jack

On Sep 16, 2021, at 6:55 AM, Davis Johnson <davis@frizzen.com> wrote:

Note that 28 is half of 56. You can double or halve either stud or screw gear and move one row on the chart.

That means you can run 56 on both stud and screw and move down to the C hole and get the same ratio. Since every lathe came with a 56 tooth gear they are reasonably plentiful on eBay.

You can also change to any stud and screw gears that give you the same ratio and stay in the same holes. 56:56 is 1:1 - so any two identical gears on stud and screw will work in holes C-1.

That means 40:40 will work in C:1.

Applying the "double or halve move one row" rule you can go to a 20 tooth stud gear and a 40 tooth screw gear and move back to hole B-1. You could have gotten here directly from 28:56 by the same ratio rule but I wanted to show that there were lots of combinations.

The great thing about 20:40 is that both of these came standard with the lathe, although the 40 tooth gear sometimes gets lost.


On 9/15/21 2:58 PM, Gl NO wrote:
Here is the info I have from a different source
M1.75
Stud gear 28
Screw gear 56
Plunger whole B
Plunger hole 1
Gear 1 127/100

I hope this is helpful.

Glenn
On Sep 15, 2021, at 2:51 PM, Jack Dinan <jack@thedinans.net> wrote:

I need to cut an M1.75 thread on my English SB9A.

I’ve ordered a 120/100 transposing gear.

In the How to run a Lathe manual:

1. In the index chart Figure 249 I see for M1.75 the combination is a 56 tooth stud gear and an 80 tooth screw gear.

2. In the chart Figure 253, for the same thread I see a 50 tooth stud gear listed.

I’m misreading these, I’m sure, but I don’t know how.

For M1.75 and a 127/100 transposing gear, what stud and screw gears should I use?











Phillip Rankin
 

Jack;

Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.

If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Jack Dinan
 

Thank you Phillip.
This is so helpful.


On Sep 17, 2021, at 12:36 PM, Phillip Rankin <phillip.rankin1964@...> wrote:

Jack;
Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.
If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.
<Metric_Thread_Chart_1.pdf><Metric_Thread_Chart_2.pdf>


G K
 

Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;

Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.

If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Carl Bukowsky
 

I just cut my first metric threads (M50-1.5) on my SB 9” Junior Model C.  I used a 3D printed 80/63 compound gear purchased off eBay.  

Important step in the process is to keep the half-nut engaged until you are complete.  That means take a cut, power down (stop at the relief groove), back out the tool, reverse motor back to beginning of thread, reset tool for next cut, rinse and repeat as they say.  

I had not wired the lathe for reverse, so I had to do that for automating the return of the tool. I also cut slow, using the back gears so the tool would coast to a dead stop at the relief groove at the end of the threading cut. 

The project I’m working on is an ER-40 collet holder and I am using a purchased collet nut hence the requirement for metric threading. I wanted to do some metric threading and I bought several other 3D printed gears besides the compound so I can do a reasonable variety of common metric sizes.   That’s all, just wanted to pass on what I experienced and encourage others. Carl

Sent by my iPhone

On Sep 18, 2021, at 8:34 AM, G K via groups.io <bug_hunter2000@...> wrote:


Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;

Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.

If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Carl Bukowsky
 



Sent by my iPhone

On Sep 18, 2021, at 11:19 AM, Carl W Bukowsky <cwbukows@...> wrote:

I just cut my first metric threads (M50-1.5) on my SB 9” Junior Model C.  I used a 3D printed 80/63 compound gear purchased off eBay.  

Important step in the process is to keep the half-nut engaged until you are complete.  That means take a cut, power down (stop at the relief groove), back out the tool, reverse motor back to beginning of thread, reset tool for next cut, rinse and repeat as they say.  

I had not wired the lathe for reverse, so I had to do that for automating the return of the tool. I also cut slow, using the back gears so the tool would coast to a dead stop at the relief groove at the end of the threading cut. 

The project I’m working on is an ER-40 collet holder and I am using a purchased collet nut hence the requirement for metric threading. I wanted to do some metric threading and I bought several other 3D printed gears besides the compound so I can do a reasonable variety of common metric sizes.   That’s all, just wanted to pass on what I experienced and encourage others. Carl

Sent by my iPhone

On Sep 18, 2021, at 8:34 AM, G K via groups.io <bug_hunter2000@...> wrote:


Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;

Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.

If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Jack Dinan
 

Carl: Wonderful.  The only metric thread that I’ve ever cut on my SB9 was that M50 and for that exact reason - to house the ER-40 collet holder.

It has been years since I’ve done so, and I’ve forgotten how I chose the gearing; hence the original posting. 

What I do recall is the amazement and thrill when that holder slipped smoothly onto the male thread I cut. 

I don’t believe I’ve had that level of satisfaction since.

I look forward to hearing the shout of joy from you.

phd

On Sep 18, 2021, at 12:19 PM, Carl Bukowsky via groups.io <cwbukows@...> wrote:

I just cut my first metric threads (M50-1.5) on my SB 9” Junior Model C.  I used a 3D printed 80/63 compound gear purchased off eBay.  

Important step in the process is to keep the half-nut engaged until you are complete.  That means take a cut, power down (stop at the relief groove), back out the tool, reverse motor back to beginning of thread, reset tool for next cut, rinse and repeat as they say.  

I had not wired the lathe for reverse, so I had to do that for automating the return of the tool. I also cut slow, using the back gears so the tool would coast to a dead stop at the relief groove at the end of the threading cut. 

The project I’m working on is an ER-40 collet holder and I am using a purchased collet nut hence the requirement for metric threading. I wanted to do some metric threading and I bought several other 3D printed gears besides the compound so I can do a reasonable variety of common metric sizes.   That’s all, just wanted to pass on what I experienced and encourage others. Carl

Sent by my iPhone

On Sep 18, 2021, at 8:34 AM, G K via groups.io <bug_hunter2000@...> wrote:


Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;
Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.
If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Carl Bukowsky
 

Jack, yeah that was a very happy moment. 

I actually practiced, a dress rehearsal of sorts before I cut the real threads, never hurts to avoid the bozo moments as much as possible. 

I got an ER-32 nut with a lot of ER-40 collets I found online.  The seller didn’t know, so I had to buy one for the project. I may make an ER-32 chuck as well, then I’ll have an excuse to get more collets. 

Carl
Sent by my iPhone

On Sep 18, 2021, at 11:25 AM, Jack Dinan <jack@...> wrote:

Carl: Wonderful.  The only metric thread that I’ve ever cut on my SB9 was that M50 and for that exact reason - to house the ER-40 collet holder.

It has been years since I’ve done so, and I’ve forgotten how I chose the gearing; hence the original posting. 

What I do recall is the amazement and thrill when that holder slipped smoothly onto the male thread I cut. 

I don’t believe I’ve had that level of satisfaction since.

I look forward to hearing the shout of joy from you.

phd

On Sep 18, 2021, at 12:19 PM, Carl Bukowsky via groups.io <cwbukows@...> wrote:

I just cut my first metric threads (M50-1.5) on my SB 9” Junior Model C.  I used a 3D printed 80/63 compound gear purchased off eBay.  

Important step in the process is to keep the half-nut engaged until you are complete.  That means take a cut, power down (stop at the relief groove), back out the tool, reverse motor back to beginning of thread, reset tool for next cut, rinse and repeat as they say.  

I had not wired the lathe for reverse, so I had to do that for automating the return of the tool. I also cut slow, using the back gears so the tool would coast to a dead stop at the relief groove at the end of the threading cut. 

The project I’m working on is an ER-40 collet holder and I am using a purchased collet nut hence the requirement for metric threading. I wanted to do some metric threading and I bought several other 3D printed gears besides the compound so I can do a reasonable variety of common metric sizes.   That’s all, just wanted to pass on what I experienced and encourage others. Carl

Sent by my iPhone

On Sep 18, 2021, at 8:34 AM, G K via groups.io <bug_hunter2000@...> wrote:


Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;
Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.
If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Bill in OKC too
 

Looking good! I just got my Atlas ready to run this morning. Need to lube it properly and it's ready to go. Got the 7x10 set up earlier this week. Need to do the Smithy next, and then it's time to get back to the restoration of my Heavy 10L. Should be easier with all those other lathes working. Would have been easier still if I only had one... but I'm a gllutton for punishment.

I'm working on an internal threading problem for class, and looking forward to the day I can do such things in my home shop.

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, September 18, 2021, 11:22:32 AM CDT, Carl Bukowsky via groups.io <cwbukows@...> wrote:




Sent by my iPhone

On Sep 18, 2021, at 11:19 AM, Carl W Bukowsky <cwbukows@...> wrote:


I just cut my first metric threads (M50-1.5) on my SB 9” Junior Model C.  I used a 3D printed 80/63 compound gear purchased off eBay.  

Important step in the process is to keep the half-nut engaged until you are complete.  That means take a cut, power down (stop at the relief groove), back out the tool, reverse motor back to beginning of thread, reset tool for next cut, rinse and repeat as they say.  

I had not wired the lathe for reverse, so I had to do that for automating the return of the tool. I also cut slow, using the back gears so the tool would coast to a dead stop at the relief groove at the end of the threading cut. 

The project I’m working on is an ER-40 collet holder and I am using a purchased collet nut hence the requirement for metric threading. I wanted to do some metric threading and I bought several other 3D printed gears besides the compound so I can do a reasonable variety of common metric sizes.   That’s all, just wanted to pass on what I experienced and encourage others. Carl

Sent by my iPhone

On Sep 18, 2021, at 8:34 AM, G K via groups.io <bug_hunter2000@...> wrote:


Any ideas on coordinating this to a 9C (No QCGB)?

No current need, but just a point of discussion.

A great weekend to all!



On Friday, September 17, 2021, 11:36:29 AM CDT, Phillip Rankin <phillip.rankin1964@...> wrote:


Jack;

Several years ago I put together a couple of charts for my own use cutting metric threads. At the time there weren’t any 3d printed transposing gears being offered on eBay, and 127/100 transposing gears for a SB 9a / 10K were out of my price range, so I needed to find combinations of change gears to work with the standard 80 tooth idler gear to render approximate metric threads. I’ve cut everything between, and including 1mm – 2mm thread pitches, and for normal thread engagement lengths these combinations have worked very well, and many are slightly better than what can be achieved if one were to us a 47/37 transposing gear.

I created Chart 1 first, and although it worked I found it somewhat lacking as it didn’t identify all the possibilities with the different gear combinations, so I created the second chart. I like it much better as it gives me a visual similar to the tag on my gearbox.

If one of the group admins could add these charts to the files I would be grateful. I believe they could be a benefit to all.

Phillip R.


Jim_B
 


--

This should help.

Jim B


Phillip Rankin
 

GK,
I've never had an opportunity to work with a 9b, or 9c. I'm sure suitable metric thread approximations can be made without the use of a transposing gear, but I have never given it any thoughts. Perhaps someone that is more familiar with 9b, 9c gear trains will chime in. Now that you brought it up I'm a bit interested myself.

Phillip R.