Thread Gearing

[Metalistico]

This is probably a dumb question, but I can't figure out this gearing, I'm trying to cut internal 18 course threads, my lathe says I need a 40 tooth in A position and a 45 in D position, Right.
Thing is, what goes in B and C position ?
Here's a couple pics for you gurus to see.
I'm assuming A is the little black gear right above the big gear, am I right ?

 

[YYCHM]

This manual will help you make more sense of it. https://littlemachineshop.com/images/gallery/Info/MiniLatheUsersGuide.pdf

No gear specified means any gear can be used.

Sure glad I don't have to deal with change gears anymore

 

[RobinHood]

x2 what Craig said.

You are looking for this configuration (yellow circle), as you have identified:



Which should result in these three shafts having a single gear on it (red arrows). Only critical thing is that the gear in A position be 40T and the gear in D position be 45T. Your choice what you can fit in B position. D position is the input shaft to the lead screw.

 

[Metalistico]

x2 what Craig said.

You are looking for this configuration (yellow circle), as you have identified:

View attachment 19370

Which should result in these three shafts having a single gear on it (red arrows). Only critical thing is that the gear in A position be 40T and the gear in D position be 45T. Your choice what you can fit in B position. D position is the input shaft to the lead screw.

View attachment 19372

That's the problem I put the 40 gear in A position and 45 in D position but then I can't find a gear that will fit in B position that will engage everything and work the lead screw

 

[YYCHM]

That's the problem I put the 40 gear in A position and 45 in D position but then I can't find a gear that will fit in B position that will engage everything and work the lead screw

The B and C gears on on an adjustable bracket. You can position the bracket such that the gears will mesh and that's why I really didn't like change gears. See page 26 of the LMS pdf I posted.

 

[Metalistico]

The B and C gears on on an adjustable bracket. You can position the bracket such that the gears will mesh and that's why I really didn't like change gears.

Yeah I've played with the banjo adjustment and still no go, what a pain in the ass yes.
I think I may have the answer, witch was in the manual you sent me, it says that the D pulley you need to reverse the spacer on it.

 

[Metalistico]

I'm gona go see if this works right now

 

[Metalistico]

SOB, that's all it was lmao

 

[RobinHood]

Good you got it sorted.

 

[Bofobo]

Once you get through the few learning curves of these machines, understanding it’s under powered and getting familiar with its other limits it will do things the internet said are impossible. To be honest when I move I’ll likely need to down size back to one again