Date   

Re: Metric

fwhite913
 

Thank you for your help, but the other individual has stated you can cut threads that are close with an inch gearbox and leadscrew.  I was inquiring what settings for the "inch" gearbox would provide these results. He has declined to provide the info.

 

 

On 04/17/2018 05:26 PM, Phillip Rankin phillip.rankin1964@... [SOUTHBENDLATHE] wrote:



Is this what you are looking for? You can find it in the files section. Files,Techinfo, metric threading, metricgearchart.jpg

On Tue, Apr 17, 2018, 2:17 PM 913fred@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:
 

 

So if I had ( for example ) a 100/127 tooth transposing gear set installed and a 36T stud gear, what would the QC box settings be?   To get .25mm pitch, I would set the QC box to what TPI setting?  How accurate would that be?

Would you please provide a table of settings for 0.25 to 1.25MM pitches.

Thank you for your information.

 

 

On 04/17/2018 01:58 PM, vtsblogan@... [SOUTHBENDLATHE] wrote:

[Attachment(s) from vtsblogan@... included below]

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes  I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.
 


 

 



 
 


 


Re: Metric

carbure2003
 

IT is to be noted that with the transposing gears, for many pitch, there are more than one combination possible.

When I have to cut more than one metric pitch for a project, I usually study my calculated gear chart and check the optimum setup in order not to have to change gears in between operations. I had posted my spreadsheet on the group many years ago but it seems to have disappeared.

We have been talking of metric threading on standard south bend. A few of us have metric south bend lathes. If you want to cut standard thread on a metric south bend, the transposing gear required is 135-127

Spreadsheet development for threading is much more simple than dividing combinations on a dividing head.

I had done the whole calculations in a MS access database, but I lost the file in a hard drive failure. I did the same thing for the atlas lathe. I used the speradsheet only once in 10 years when I had to cut a19tpi thread for a special UK pipe fitting required at short notice.

Playing with gear settings posted today for BA threads, I found a few odd gear setups for BA threads.
Imwill play a little bit more wi5 the spreadsheet. In some cases, we can get close approximations without transposing gear.

Guy Cadrin




____________________________________________________________
He Transformed His Gut With One Thing
gundrymd.com
http://thirdpartyoffers.netzero.net/TGL3241/5ad69ad6101601ad57fc2st02vuc


Re: Our 1915 South Bend Lathe Series O, 15-inch

t0834dep
 

Nice Job Gregg. I picked up a #5 Cullman Speed reducer catalog off ebay for some drive ideas.


Re: Metric

vtsblogan@...
 

I'm not going to sit here and prepare a gear chart for you- get the Cleeve book (or any one of the various ones that deal with this) and figure it out.

The 100/127 gear is not an accident- 1"= 2.54 cm. In order to get rid of the decimal you multiply (100)  and come out with 254teeth. Obviously a 254 tooth gear won't fit on the lathe so it's halved to 127tooth, which is as far as it can go with a whole tooth.  The 100/127 cuts perfect Metric threads whether it's used on a QC or change gear lathe.

The 37/47 ratio is used because it's close, but the small sized gears make for a convenient setup within the lathe- and many (non South Bend) lathes won't allow a 100/127 combo to fit. Going from memory the 37/47 gears give something like 1/100 or 2/100 of 1 percent of accuracy.

Every SB Transposing gear I have seen contains a chart for all threads it can cut.

I usually cut threads on my Logan instead of my SB- but the SB goes something like this with the 100/127 gears in place- for the .25 pitch use a 32 stud gear and a 56 on the screw (QC) that should put your left hand QC lever in the "E" position and the right hand lever in the "First" slot. Now go take a look at your chart mounted on the QC box and you'll see that moving the left lever from "E" to "D" to "C" (and so on) the lathe cuts half again each time. So .25 pitch becomes .5, then 1.0 to 2.0 to 4 etc- Understand?

With the QC pretty much all common Metric threads will use the 56 on the screw, you just change the stud gear.

Hence my original E- mail where I said a QC is very flexible, and one stud gear change gives you multiple threading pitches.

 

On Tue, 17 Apr 2018 14:17:29 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

So if I had ( for example ) a 100/127 tooth transposing gear set installed and a 36T stud gear, what would the QC box settings be? To get .25mm pitch, I would set the QC box to what TPI setting? How accurate would that be?

Would you please provide a table of settings for 0.25 to 1.25MM pitches.

Thank you for your information.

 

 

On 04/17/2018 01:58 PM, vtsblogan@... [SOUTHBENDLATHE] wrote:

[Attachment(s) from vtsblogan@... included below]

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:
 

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.


 

 



 

 


Re: Metric

Phillip Rankin
 

Is this what you are looking for? You can find it in the files section. Files,Techinfo, metric threading, metricgearchart.jpg


On Tue, Apr 17, 2018, 2:17 PM 913fred@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:
 

So if I had ( for example ) a 100/127 tooth transposing gear set installed and a 36T stud gear, what would the QC box settings be?   To get .25mm pitch, I would set the QC box to what TPI setting?  How accurate would that be?

Would you please provide a table of settings for 0.25 to 1.25MM pitches.

Thank you for your information.

 

 

On 04/17/2018 01:58 PM, vtsblogan@... [SOUTHBENDLATHE] wrote:

[Attachment(s) from vtsblogan@... included below]

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes  I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.
 


 

 



 


Re: Our 1915 South Bend Lathe Series O, 15-inch

Gregg Eshelman
 

I used the smallest putty kit from Moglice. After applying the included release agent to the unworn right end of the leadscrew I just clamped them to it. What was left of the threads aligned the half nuts. Prep of them was bead blasting, soaking in lacquer thinner, letting dry completely followed by using the cleaner in the Moglice kit.


On Tuesday, April 17, 2018, 1:34:51 AM MDT, Edward Draper eddie.draper@... [SOUTHBENDLATHE] wrote:


Gregg,

I can see how you fixed the absence of threads on the split nut, but can you explain how you ensured the 2 halves were in phase with each other, please?  I thought I was going to have to do something similar on our 15" (30" US) Broadbent, but it turned out the nuts were just packed with swarf.

Did you use whitemetal or some sort of resin?

Thanks,

Eddie


Cross slide screw thread

benjithestupiddog@...
 

Hi all,


Quick question, more a sanity check before I do something stupid.


The thread on the end (end that holds the nut for the handle) of my cross slide screw is pretty mangled and i want to try and save it, can anyone confirm what thread it is please.


I would like to buy a die and try and clean it up but don't want to get the wrong one.


Re: Metric [1 Attachment]

fwhite913
 

When I try to open the attachment, I get a pink rectangle with no content.

 

 

On 04/17/2018 01:58 PM, vtsblogan@... [SOUTHBENDLATHE] wrote:

[Attachment(s) from vtsblogan@... included below]

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes  I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.
 


 

 



 


Re: Metric [1 Attachment]

fwhite913
 

So if I had ( for example ) a 100/127 tooth transposing gear set installed and a 36T stud gear, what would the QC box settings be?   To get .25mm pitch, I would set the QC box to what TPI setting?  How accurate would that be?

Would you please provide a table of settings for 0.25 to 1.25MM pitches.

Thank you for your information.

 

 

On 04/17/2018 01:58 PM, vtsblogan@... [SOUTHBENDLATHE] wrote:

[Attachment(s) from vtsblogan@... included below]

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes  I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.
 


 

 



 


Re: Metric

vtsblogan@...
 

I think this is pretty well known. It pays to learn gear ratio formulas of course- Martin Cleeve's book explains this well, and though he is talking about change gear lathes, as long as you allow for the QC it works.

There are several metric pitches that can get pretty darn close with standard English overlaps.

Once you insert the transposing gears- I use 37/47 because it's more convenient and I don't cut metric much- it really is close enough for virtually all work, but of course you need the 100/127 for perfect match.

I'm using gears from my Logan here, because I have it right in front of me, but the same holds true for the SB lathes (stud gear may change though) With transposing gears in place, and a 36 stud gear I can cut pretty much any .25 metric multiple- .25, .50. .75, 1, 1.25 etc just by changing the QC lever- because a lot of the QC halves itself (or other ratios as well) as in 20tpi setting and 40 tpi setting etc are just like adding in an extra set of compound gearing into the mix. I.E. the QC at 8 TPI is 1:1, QC at 16TPI is 1:2

Compare that to the change gear lathes  I think you would see that the QC is hardly "extremely limited"

Hope I'm making that clear.

On Tue, 17 Apr 2018 13:04:12 -0500, "913fred@... [SOUTHBENDLATHE]" wrote:

 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In additionto all but therarestEnglish threads, you havethe ability to instantly change your feed rate- something that isfar more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threadsas the Model C since you can also use the Metric Conversion gears on the Model A as well. And you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.
 


 

 


Re: Metric

fwhite913
 

>>In addition, you can cut Metric threads very, very closely with but one gear change

Please explain further....Thanks

 

 

On 04/17/2018 10:49 AM, vtsblogan@... [SOUTHBENDLATHE] wrote:



 palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In addition to all but the rarest  English threads, you have the ability to instantly change your feed rate- something that is far more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threads as the Model C since you can also use the Metric Conversion gears on the Model A as well.  And  you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.

 


 


Metric

vtsblogan@...
 

 palciatore@... not to sidetrack your discussion, or open a can of worms, but to call a QC gearbox "Extremely Limited" is silly. In addition to all but the rarest  English threads, you have the ability to instantly change your feed rate- something that is far more valuable. In addition, you can cut Metric threads very, very closely with but one gear change, and you can cut all of the same Metric threads as the Model C since you can also use the Metric Conversion gears on the Model A as well.  And  you can still instantly change feed rates with the Metric gears in place if you need to do a non- threading operation on a part.

 


Re: Our 1915 South Bend Lathe Series O, 15-inch

eddie.draper@btinternet.com
 

Gregg,

I can see how you fixed the absence of threads on the split nut, but can you explain how you ensured the 2 halves were in phase with each other, please?  I thought I was going to have to do something similar on our 15" (30" US) Broadbent, but it turned out the nuts were just packed with swarf.

Did you use whitemetal or some sort of resin?

Thanks,

Eddie



From: "Gregg Eshelman g_alan_e@... [SOUTHBENDLATHE]" <SOUTHBENDLATHE@...>
To: "t0834dep@... [SOUTHBENDLATHE]"
Sent: Tuesday, 17 April 2018, 6:25
Subject: Re: [SOUTHBENDLATHE] Our 1915 South Bend Lathe Series O, 15-inch

 
Nice old lathe. Here's how dad and I mounted a drive setup on a similar age Sears Expert (made by South Bend) of similar age. The main bit was putting 1/4" steel plates between the legs and bed, with the one at the headstock end extended out the rear to hang it all on. We also gave it a foot pedal to tilt the drive forward for super easy belt speed changes.


On Monday, April 16, 2018, 5:52:31 PM MDT, t0834dep@... [SOUTHBENDLATHE] wrote:


[Attachment(s) from t0834dep@... included below]

Still a line drive machine.

Attachment(s) from t0834dep@... | View attachments on the web
1 of 1 Photo(s)

Posted by: t0834dep@...




Re: Our 1915 South Bend Lathe Series O, 15-inch [1 Attachment]

Gregg Eshelman
 

Nice old lathe. Here's how dad and I mounted a drive setup on a similar age Sears Expert (made by South Bend) of similar age. The main bit was putting 1/4" steel plates between the legs and bed, with the one at the headstock end extended out the rear to hang it all on. We also gave it a foot pedal to tilt the drive forward for super easy belt speed changes.


On Monday, April 16, 2018, 5:52:31 PM MDT, t0834dep@... [SOUTHBENDLATHE] wrote:


[Attachment(s) from t0834dep@... included below]

Still a line drive machine.

Attachment(s) from t0834dep@... | View attachments on the web

1 of 1 Photo(s)


Posted by: t0834dep@...


Re: metric threads:

jim and rose
 

 
 
Thought you might like the chart
 

From: palciatore@... [SOUTHBENDLATHE]
Sent: Monday, April 16, 2018 8:15 PM
To: SOUTHBENDLATHE@...
Subject: Re: [SOUTHBENDLATHE] Re: metric threads:
 
 

I have a SB9C which has manual change gears. If you have a QC gear box, which are so limiting, then this does not apply. I have a full set of change gears plus additional sizes, a 127:100 compound and three additional compounds (1:3, 1:4, and 1:6). These give me a large number of possible combinations of gears. I have an Excel spreadsheet where I have calculated the resultant thread pitch with all possible combinations of these gears to include gear trains up to: Stud Gear, 127:100 compound, one additional compound, and the Screw Gear. That's about all that will fit on a two arm banjo. I checked the pitches of the BA thread series in Wikipedia and looked for them in my complete table of possible metric threads. But keep in mind that I have not actually tried to set up all these combinations so some of them may not be physically possible without additional idler gears. Here are the results that I found.

I do not know how to make an actual table here so my format, with items separated by commas, is as follows: BA number, BA Pitch, Pitch Found (Y/N), If No then closest pitch found, Stud Gear, Screw Gear, Compound used (if any).

BA-0, 1mm, Y, na, 16, 40, none
BA-1, 0.9mm, Y, na, 36, 100, none
BA-2, 0.81mm, N, 0.825mm, 26, 80, none
BA-3, 0.73mm, N, 0.729..mm, 28, 32, 3:1
BA-4, 0.66mm, Y, na, 16, 60, none
BA-5, 0.59mm, N, 0.595..mm, 20, 28, 3:1
BA-6, 0.53mm, N, 0.53030..mm, 28, 44, 3:1
BA-7, 0.48mm, N, 0.4792..mm, 46, 80, 3:1
BA-8, 0.43mm, N, 0.4297..mm, 22, 32, 4:1

ALL of these combinations also use the 127:100 compound gear so a two arm banjo is going to be FULL. As you can see, this is a very strange series of thread sizes. Both the present English and metric standard thread sizes were chosen with gear ratios that were going to be present in a more or less standard series of gears. These were NOT. They were based on a geometric ratio and then that appears to be rounded to two decimal places in the metric sizes. Most of the ones where I did not have an exact solution are pretty close and I doubt that they would be any problems using them.

But, as I said above, I have not tried to actually use any of these combinations on my SB and some of them may not be physically possible to set up. Some may need an additional idler gear to connect gear teeth at some point: gears used as Idlers can be of any tooth count because they do not change the ratio in the gear chain. There were some alternate gear combinations in my chart for some of the sizes: I just tried to pick the simplest one. So if you try any of these and they do not work, I can provide additional combinations to try. I can also provide additional BA sizes if you want/need them as my chart goes down to 0.0574...mm. That would cover beyond the BA-25 size shown on the Wikipedia page. If you would like it, I can try to find a way to post the Excel worksheet with these numbers on it.


Virus-free. www.avg.com


Re: metric threads:

Paul Alciatore
 

I have a SB9C which has manual change gears. If you have a QC gear box, which are so limiting, then this does not apply. I have a full set of change gears plus additional sizes, a 127:100 compound and three additional compounds (1:3, 1:4, and 1:6). These give me a large number of possible combinations of gears. I have an Excel spreadsheet where I have calculated the resultant thread pitch with all possible combinations of these gears to include gear trains up to: Stud Gear, 127:100 compound, one additional compound, and the Screw Gear. That's about all that will fit on a two arm banjo. I checked the pitches of the BA thread series in Wikipedia and looked for them in my complete table of possible metric threads. But keep in mind that I have not actually tried to set up all these combinations so some of them may not be physically possible without additional idler gears. Here are the results that I found.

I do not know how to make an actual table here so my format, with items separated by commas, is as follows: BA number, BA Pitch, Pitch Found (Y/N), If No then closest pitch found, Stud Gear, Screw Gear, Compound used (if any).

BA-0, 1mm, Y, na, 16, 40, none
BA-1, 0.9mm, Y, na, 36, 100, none
BA-2, 0.81mm, N, 0.825mm, 26, 80, none
BA-3, 0.73mm, N, 0.729..mm, 28, 32, 3:1
BA-4, 0.66mm, Y, na, 16, 60, none
BA-5, 0.59mm, N, 0.595..mm, 20, 28, 3:1
BA-6, 0.53mm, N, 0.53030..mm, 28, 44, 3:1
BA-7, 0.48mm, N, 0.4792..mm, 46, 80, 3:1
BA-8, 0.43mm, N, 0.4297..mm, 22, 32, 4:1

ALL of these combinations also use the 127:100 compound gear so a two arm banjo is going to be FULL. As you can see, this is a very strange series of thread sizes. Both the present English and metric standard thread sizes were chosen with gear ratios that were going to be present in a more or less standard series of gears. These were NOT. They were based on a geometric ratio and then that appears to be rounded to two decimal places in the metric sizes. Most of the ones where I did not have an exact solution are pretty close and I doubt that they would be any problems using them.

But, as I said above, I have not tried to actually use any of these combinations on my SB and some of them may not be physically possible to set up. Some may need an additional idler gear to connect gear teeth at some point: gears used as Idlers can be of any tooth count because they do not change the ratio in the gear chain. There were some alternate gear combinations in my chart for some of the sizes: I just tried to pick the simplest one. So if you try any of these and they do not work, I can provide additional combinations to try. I can also provide additional BA sizes if you want/need them as my chart goes down to 0.0574...mm. That would cover beyond the BA-25 size shown on the Wikipedia page. If you would like it, I can try to find a way to post the Excel worksheet with these numbers on it.


Re: Our 1915 South Bend Lathe Series O, 15-inch

t0834dep
 

SBL sn7644 15in x7ft    5-May-1916  O series   Cat37-D


Our 1915 South Bend Lathe Series O, 15-inch

t0834dep
 

Still a line drive machine.


Re: metric threads:

Guenther Paul
 

Bill Meyers just bought a 3D ask him he may make you some gears 
GP


On Friday, April 13, 2018 2:06 PM, "Guenther Paul paulguenter@... [SOUTHBENDLATHE]" wrote:


 
You can have them made by a friend with a 3D printer I use 1 gear on my atlas works just fine. If you go that rout make sure they are printed solid You can save some $$$$$$ 
GP


On Friday, April 13, 2018 7:35 AM, "William Meyers wmrmeyers@... [SOUTHBENDLATHE]" wrote:


 
Thanks, Guy! I don't have a quick change gearbox for my TH42 yet, hope one day to fix that problem. Do have, I think, two sets of plans for DIY gearboxes, and with the 3D printer may have economical means of making the gears for one of those. I was a little scared by the cost of individual gears. I found metric transposition gears that would work on my Atlas on Amazon.com, but at over $200 for two gears and the bushing it didn't look practical.  Then I saw Mr. Pete222's you-tube video on 3D-printed change gears for his Atlas.

Since I also wanted a set of metric transposing gears for the HF 7X10, and couldn't find them anywhere, and a dividing head that would fit my mill looked to be about $300, and would also require special milling cutters for each pitch of gear, SWMBO authorized the 3D printer. Got lots to learn, but I'm on my way.

Bill in OKC 


On Fri, Apr 13, 2018 at 3:23 AM, 'guycad@...' guycad@... [SOUTHBENDLATHE]
wrote:
For atlas lathe quick change attachment handbook, I uploaded the publication on the vintage machinery web site


I realised I missed 2 pages on the scan, threads 1.25 tpi to 2 tpi, but you will never thread that kind of thread.

When I get to my computer, I will try to dig the spreadsheet.

Guy

---------- Original Message ----------
From: "William Meyers wmrmeyers@... [SOUTHBENDLATHE]" <SOUTHBENDLATHE@...>
Subject: Re: [SOUTHBENDLATHE] Re: metric threads:
Date: Fri, 13 Apr 2018 05:12:12 +0000 (UTC)



Guy, I'd be interested in all the info you've acquired on threading in the Atlas lathes. I'm in process of learning to thread on the lathe in my class, and bought a 3D printer to make metric transposition gears for it and my HF 7x10 lathe. Got the HF gears printed, trying to learn how to do the Atlas gears myself.
  I would be particularly interested in info on the SB lathes, as well. So far, I've been a day late & a dollar short, at least, on all the SB lathes that have been on offer here since I learned how to look for them but that can't last forever. I hope, anyway. :) Have been following the di! scussion on the metric transposing gears for the SB, trying to relate it to what I've learned of the Atlas & HF machines.  Bill in OKC
 
Sent from Yahoo Mail on Android
Snip!





Re: metric threads:

Guenther Paul
 

You can have them made by a friend with a 3D printer I use 1 gear on my atlas works just fine. If you go that rout make sure they are printed solid You can save some $$$$$$ 
GP


On Friday, April 13, 2018 7:35 AM, "William Meyers wmrmeyers@... [SOUTHBENDLATHE]" wrote:


 
Thanks, Guy! I don't have a quick change gearbox for my TH42 yet, hope one day to fix that problem. Do have, I think, two sets of plans for DIY gearboxes, and with the 3D printer may have economical means of making the gears for one of those. I was a little scared by the cost of individual gears. I found metric transposition gears that would work on my Atlas on Amazon.com, but at over $200 for two gears and the bushing it didn't look practical.  Then I saw Mr. Pete222's you-tube video on 3D-printed change gears for his Atlas.

Since I also wanted a set of metric transposing gears for the HF 7X10, and couldn't find them anywhere, and a dividing head that would fit my mill looked to be about $300, and would also require special milling cutters for each pitch of gear, SWMBO authorized the 3D printer. Got lots to learn, but I'm on my way.

Bill in OKC 


On Fri, Apr 13, 2018 at 3:23 AM, 'guycad@...' guycad@... [SOUTHBENDLATHE]
wrote:
For atlas lathe quick change attachment handbook, I uploaded the publication on the vintage machinery web site


I realised I missed 2 pages on the scan, threads 1.25 tpi to 2 tpi, but you will never thread that kind of thread.

When I get to my computer, I will try to dig the spreadsheet.

Guy

---------- Original Message ----------
From: "William Meyers wmrmeyers@... [SOUTHBENDLATHE]" <SOUTHBENDLATHE@...>
Subject: Re: [SOUTHBENDLATHE] Re: metric threads:
Date: Fri, 13 Apr 2018 05:12:12 +0000 (UTC)



Guy, I'd be interested in all the info you've acquired on threading in the Atlas lathes. I'm in process of learning to thread on the lathe in my class, and bought a 3D printer to make metric transposition gears for it and my HF 7x10 lathe. Got the HF gears printed, trying to learn how to do the Atlas gears myself.
  I would be particularly interested in info on the SB lathes, as well. So far, I've been a day late & a dollar short, at least, on all the SB lathes that have been on offer here since I learned how to look for them but that can't last forever. I hope, anyway. :) Have been following the di! scussion on the metric transposing gears for the SB, trying to relate it to what I've learned of the Atlas & HF machines.  Bill in OKC
 
Sent from Yahoo Mail on Android
Snip!


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