What TPI on leadscrew of 6" Atlas lathe?

[John Buffum]

There's a nice article in Projects three about building a threading gearbox for a lathe. I have an 1885 F.E. Reed. I have only a few of the change gears. I'd like to retrofit it with such a grearbox. The lead screw on the Reed is 5 TPI. I'd need to establish a gear or chain and sprocket system that would allow me not to have to do the math to recalculate all the gears to match my leadscew. Any info out there?

An update on the Reed. I had to disassemble the headstock and clean out a handful of old, congealed grease. Now, the back gear works wonderfully. The industrial belt from McMaster-Carr for $40 is a wonder. Nylon cord imbedded in grabby rubber.

Soon to do sheet metal work. Gear shrouds and an electrics box.

May publish. Dunno.

[mattthemuppet]

1/2" x 16 tpi Acme Stub Thread as far as I'm aware, but if you want 100% sure I can check in the garage tomorrow. Have to finish some work and I'm easily distractable otherwise I'd do it now

[John Buffum]

Thanx. Yes. Let's make sure before I start buying stuff.

[mattthemuppet]

double checked this morning, it is indeed 1/2" x 16tpi. I can't be +ve about the type of thread but it looks like Acme to me - squarish and not pointy

[John Buffum]

OK. That means I'd hafta speed up the Reed leadscrew by 16:5. Perhaps bicycle chain and a 48 tooth driver and a 15 tooth driven. Got lotsa bicycle chain. Hafta make the sprockets. All the gears in the article are for your lathe. The author made his outta brass. I'm going with cast iron, or mild steel. Your motor is 1/3hp, mine is 1 hp DC. My leadscrew is 1-1/4" in diameter.

Ooh. Just a thot. Cutting speeds and thread speeds are way different. Hmmm. More thinking to do.

[mattthemuppet]

that's all waaay above my pay grade But if there's anything else 618 I can help out with, let me know!

[Don Young]

OK. That means I'd hafta speed up the Reed leadscrew by 16:5. Perhaps bicycle chain and a 48 tooth driver and a 15 tooth driven. Got lotsa bicycle chain. Hafta make the sprockets. All the gears in the article are for your lathe. The author made his outta brass. I'm going with cast iron, or mild steel. Your motor is 1/3hp, mine is 1 hp DC. My leadscrew is 1-1/4" in diameter.

Ooh. Just a thot. Cutting speeds and thread speeds are way different. Hmmm. More thinking to do.

No, you need to slow down the 5 TPI screw to travel the same distance as the 16 TPI screw. If you don't want to get into some really big gears or sprockets you might want to consider compound gearing. For turning, you could make a separate variable speed motor drive. Think it through carefully, what you are suggesting is a pretty big job.