Making a 127/100 tooth gear set for metric screw cutting on an imperial lathe.

[@graedonmunro1793]

G'day mate ,, only just found you. great vid and look forward to more, cheers

[@docsofftopic8130]

Welcome to the shop mate

[@y-notforge8913]

..this like most machining operations is out of my wheelhouse, but like Spock said- Fascinating...

[@docsofftopic8130]

I know, sometimes you just have to throw caution to the wind and have a go

[@packapunchburger]

Well that's a new workout to try

[@mr.ranyhomemade2466]

Thanks for your shared, I wondering car I do the diameter gear different or must be the same diameter? Thanks

[@docsofftopic8130]

It depends on the tooth pitch, larger tooth pitch (smaller teeth) has a smaller wheel size. There are online calculators to help you work out the size you need for a given tooth count.

[@mr.ranyhomemade2466]

@@docsofftopic8130 thanks, definitely tooth pitch just different in diameter only. I have bought some scrape gears here so expensive. Thank for recommended.

[@KSMechanicalEngineering]

Nice

[@docsofftopic8130]

And the gear has worked a treat for the current job on the bench, TR8x2 done and dusted

[@mhc6777]

Nice work Doc, looks like you are getting on well with your new mill. You mentioned cutting the teeth with the mill in reverse (counter clockwise) because of manufacturer's recommendations - is there any reason it wouldn't work cutting clockwise and feeding left to right? Just asking for people whose mill doesn't have reverse.

[@docsofftopic8130]

I suspect it’s because the tooth profile might not be centred on the cutter blank they use, but if they are all made the same way then it should be a given distance from one side cutter to cutter. But so long as you center the tooth accurately there shouldn’t be a reason it wouldn’t work. Provided the cutter is oriented correctly, turning it upside down would reverse the required rotation to cut.

[@jasonbell5905]

You said single point?

[@docsofftopic8130]

Yes, it’s a work around for the steel used (work hardened suckerrod), then for the metric threads at least the get trued up with a die once cut to approx 75% of full depth.

[@greggarnham8497]

14 TPI is nowhere near 1.75mm pitch, its actually about 1.81mm . . . . I found that even a horribly overcut 14TPI would only engage an M40 x 1.75 collar for 2 or 3 turns before it bound up. Thats why I've just had to make some new change gears for my lathe (a 28T, 35T and 37T. Any one of them would have done, but I cut all 3 because I'd already spent the time doing the maths, and because it was fun !) Now I have 3 options to achieve 1.75 mm.

[@docsofftopic8130]

At 12, so Lo g as you chase it with a die post cutting (don’t cut to full depth) you get three or so slightly over cut threads at the inboard end over 20mm you only need 6 turns to reach the max yield for a give thread. So well more than I needed for this.

[@greggarnham8497]

@docsofftopic8130 Yeah, that would have worked, if I could get an M40 x 1.75 die ! I was stuck with single pointing it . . . . As I say, good excuse to make some gears !

[@ita-1245]

What misting fluid do you use?

[@docsofftopic8130]

Semi-synthetic water soluble, local brand is XDP-139, about 10% solution.

[@lohikarhu734]

There's a smaller tooth ratio thats really, really close...0.06% 33/13 = 2.5385 2.5385 / 2.54 = 0.9994

[@docsofftopic8130]

I know but I’ll be doing some relatively long sections of thread so need them as accurate as possible as some are feed screws for lathes I’m restoring/rebuilding

[@lohikarhu734]

Gotcha! Clear!

[@mfs5493]

POOR TO NON-EXISTENT EDITING, UNPREPARED, OFF.THE-CUFF COMMENTARY.

[@docsofftopic8130]

And? It’s my channel don’t like it don’t stick around

[@randombiopod7384]

I'm staying, really appreciate your comments and production, real and informative, thankyou