[HELP] Possible Lathe Threads

[EdK]

I know most lathes are capable of cutting more threads than the manufacturers claim. I'd like to figure out every possible thread my lathe can cut. My lathe has kind of a strange gear configuration in that it seems to have more gears than other lathes. I've seen people create spreadsheets that will do the calculations but I haven't been able to figure out how to do that. Anybody ever created such a spreadsheet? Below is an image of the gear train of my lathe. The drawing shows the gears set up for 8TPI.

Lead screw TPI is 8.

Ed

               

[Vinny]

Lead screw TPI?

[EdK]

(04-29-2017, 11:12 AM)Vinny Wrote: Lead screw TPI?

Oops! It's 8TPI.

Ed

[dallen]

I think this is what Ed's looking for or something close to it.


  gear.xls (Size: 297 KB / Downloads: 21)

[Vinny]

Here's the formula for the tpi of your gears.

From your pic, I'm going to number (letter) your gears.

A: 32
B: 64
C: 42
D: 91
E: 86
F: 21
X: 0.94545
Y: LS TPI (8 in your case)

(B/A) * (D/C) * (F/E) * Y * X = TPI.

A word about X. X is the Kludge factor since the 32 tooth gear isn't spinning at the same speed as the spindle. X is actually 32/S with S being the number of teeth on the spindle's gear.

I haven't looked at the XLS that Dallen posted, but one thing you need to take into consideration is the distance between the lead screw gear and the 32 tooth stud gear - it could be that they don't mesh or they don't fit.

I'm pretty sure I have my math right, you'll wanna double check it.

[EdK]

(04-29-2017, 04:31 PM)Vinny Wrote: Here's the formula for the tpi of your gears.    

From your pic, I'm going to number (letter) your gears.  

A: 32
B: 64
C: 42
D: 91
E: 86
F: 21
X: 0.94545
Y: LS TPI (8 in your case)

(B/A) * (D/C) * (F/E) * Y * X = TPI.

A word about X.  X is the Kludge factor since the 32 tooth gear isn't spinning at the same speed as the spindle.  X is actually 32/S with S being the number of teeth on the spindle's gear.

I haven't looked at the XLS that Dallen posted, but one thing you need to take into consideration is the distance between the lead screw gear and the 32 tooth stud gear - it could be that they don't mesh or they don't fit.

I'm pretty sure I have my math right, you'll wanna double check it.

Vinny,

The 86 tooth gear is used for metric threads only and the 91 tooth is for imperial threads only. As drawn in the image, just the 91 tooth gear is engaged with other gears. It's kind of hard to see that in the image since the gears are so close in diameter. The 86 tooth gear is just along for the ride since the two form a compound gear.

Also, doesn't the gearing in the gear box have to be included in the formula somehow? The 21 tooth gear would be driving the gears in the gear box which in turn drive the lead screw.

Ed

[Vinny]

By showing change gears I figured you opted for a cheaper model than one with a gearbox. I'll do some more figgerin.

[dallen]

even with the quick change box on the lathe there are still thread pitches that you will need to change gears to be able to turn them

[EdK]

(04-29-2017, 09:06 PM)dallen Wrote: even with the quick change box on the lathe there are still thread pitches that you will need to change gears to be able to turn them

Oh, I already know that. I'm looking to find every possible thread pitch my lath is capable of. If I have to change gears, then so be it.

Ed

[Norton Dommi]

Hello EdK,
I have just sent you an E-mail but have now found the program I talked about online so here is the link.
http://lathegears.software.informer.com/

This program is the best thing since sliced bread and I am sure you will like it.