South Bend documentation

[kitno455]

Can you post a picture of the threading chart on the front of the gearbox? I can try to work up some options. Also, I want to point out that you can use Module gears instead of DP, if all the gears on the end of the lathe are changed. That might actually be cheaper for you in europe.

 

[acd_ex]

Can you post a picture of the threading chart on the front of the gearbox? I can try to work up some options. Also, I want to point out that you can use Module gears instead of DP, if all the gears on the end of the lathe are changed. That might actually be cheaper for you in europe.

I'll need the standard threads too, so a 12DP is the way to go.
If you can figure out some easy combos it would be nice.
Also, I'll need to cut a 2TPI thread, any ideas?

 

[johnoder]

Serial 7545HKE 12

From the 1950s. Neat place - I was there for the USN circa 1961

 

[johnoder]

Also, I'll need to cut a 2TPI thread, any ideas?

Here is a scan of Mr. Wells's 1943 catalog showing the older QC would do 2TPI

http://www.wswells.com/data/catalog/1943_reprint_Catalog_100C/1943_reprint_Catalog_100C.pdf

 

[john.k]

I would advise not to try to cut 2tpi.....to do this the leadscrew (assumed 6tpi) will be running 3x spindle speed ......this has the potential to break the gears .

 

[acd_ex]

I would advise not to try to cut 2tpi.....to do this the leadscrew (assumed 6tpi) will be running 3x spindle speed ......this has the potential to break the gears .

Thank you for the warning.
I'm not sure I understand why that would happen, my lack of lathe working experience is not helping me out.
Is it because of the extra load the lead screw will need to cover the distance?
Assuming ghat we keep that in mind and use very small cutting feeds, is it possible to be safe?

 

[john.k]

Best to try rotating your setup by hand to judge whether the force needed is excessive...........its quite common to cut 2tpi leads by driving the leadscrew ,and cutting the groove with a small milling device mounted to the saddle ........Ive done very long (25ft) screws with 2 tpi using this method .........only one pass is needed ,which is a big time saver.

 

[acd_ex]

Best to try rotating your setup by hand to judge whether the force needed is excessive...........its quite common to cut 2tpi leads by driving the leadscrew ,and cutting the groove with a small milling device mounted to the saddle ........Ive done very long (25ft) screws with 2 tpi using this method .........only one pass is needed ,which is a big time saver.

I see, that's interesting.
I'll keep that in mind, thank you very much.

 

[acd_ex]

A little update on the matter.
I've fabricated a little brqcket to extend the current banjo range in order to fit hmthe larger 127/100 gears.
Anyone know the pressure angle on those gears?
I'm about to print test hears and stuck on the design
20 or 14.5⁰?
I think I've read the latter somewhere but can't find it again.

 

[GenePoole]

My factory South Bend set is 14.5° PA, as are all the change gears.

 

[acd_ex]

Another question on the matter.
Regarding the way a possible 127/100 gear would engage.
Gears on the machine are 1" wide.
Screw gear axle only has a Woodruff key for the inner gear, the outer position is a "parking spot" for the spindle extra gear.
I thought I could use that position if I were to make same width gears.
I'm not sure how I can make things work as it is.
Any ideas?
All I can think of is extending the Woodruff key to engage the outer gear on the screw gear shaft.

 

[GenePoole]

Another question on the matter.
Regarding the way a possible 127/100 gear would engage.
Gears on the machine are 1" wide.
Screw gear axle only has a Woodruff key for the inner gear, the outer position is a "parking spot" for the spindle extra gear.
I thought I could use that position if I were to make same width gears.
I'm not sure how I can make things work as it is.
Any ideas?
All I can think of is extending the Woodruff key to engage the outer gear on the screw gear shaft.

The factory transposing gears have a spacer bushing that goes behind that gear position to move it into the proper engagement orientation with the second gear in the transposing stack. My 48/64 stack has a straight key that goes through both slots on both gears. There is no Woodruff slot on mine.

 

[acd_ex]

The factory transposing gears have a spacer bushing that goes behind that gear position to move it into the proper engagement orientation with the second gear in the transposing stack. My 48/64 stack has a straight key that goes through both slots on both gears. There is no Woodruff slot on mine.

Forgive my lack of proper terminology, English is not my native language. I guess what I was trying to say is that there's only enough slot for the inner gear on the scree axle for a straight key.
As you can see on the pic, the outer part has no slot at all.
Would you happen to have any pics of that spacer bushing so I can understand how it works?

 

[Erich]

Catalog above from 1943 shows gear box is good for 4 tpi to 224 tpi. Not 2 tpi.

 

[GenePoole]

Forgive my lack of proper terminology, English is not my native language. I guess what I was trying to say is that there's only enough slot for the inner gear on the scree axle for a straight key.
As you can see on the pic, the outer part has no slot at all.
Would you happen to have any pics of that spacer bushing so I can understand how it works?

Ah, OK. I would have guessed that you were a native speaker based on the thread so far.

I can sort-of tell from your photo, but not until you pointed it out. I can't find any pictures of mine, but I'm pretty sure that it is a straight key (Woodruffs are semicircular or "half-moon" shaped) and slot long enough to drive two stacked gears (or a gear and a bushing stacked). The bushing is the same thickness as the gears, but on my 13 inch, the gears are only 5/8 inch thick.

 

[acd_ex]

If you zoom here, you can see there's a slot for a straight key for the gear in place, but on the rest of the axle there's none.
Just a blank spot for the extra spindle gear to park.
If there was a metric kit designed for this machine, how was it meant to work?

 

[GenePoole]

I have no idea. I would think that you would need to cut that slot out to the end.

 

[acd_ex]

Catalog above from 1943 shows gear box is good for 4 tpi to 224 tpi. Not 2 tpi.

"Good for" stands for capable with the gears provided, or capable to hold up to the load?

 

[Erich]

I'm going out on a limb here and say if South bend designed it to do 4 tpi. It can do 4 tpi and not break the first time you try it.
Of course the lathe is now 75 years old with an unknown maintenance history.

 

[acd_ex]

I have no idea. I would think that you would need to cut that slot out to the end.

Either that, or maybe bolt the two gears together if the first option is not possible

Also, does anyone know where I could get a wiring diagram for the electric part of the machine?
That would really help the remaining works.