Lead screw question.

[Exuptoy]

Cheers @wa5cab that makes sense. Now I sort of have my head around the gear selection process I’ll set it up for turning but maybe I’ll keep the gears for threading marked up somehow and set it up for slow feed turning. Makes perfect sense now you mention it!

@timmeh funny you should mention this as I was up the garage till gone midnight last night, initially to try and change out the gears then I got a little annoyed with the minor amount of backlash in the saddle so took the saddle off for inspection and when I removed the lead screw I noticed the gearbox had an issue. There is a hairline crack along the top alongside the banjo but it is still in serviceable condition, however, I found the yoke which selects forward /reverse doesn’t hold the transfer gear in the central position. I found one of the little fingers which push the transfer gear was missing!
I made one up from a piece of 3mm wall steel box section with a 3mm pin.

You can see in the straight up (N) position that the yoke doesn’t hold the transfer gear perfectly central.





This item was missing its pair!





I have made and fitted the finger follower but have not yet reassembled things. If it cures my ills I’ll post a full thread explaining the repair for others if required.

 

[Exuptoy]

Well, the repair made no difference but since changing gears to 32tpi gearing it’s certainly running sweeter and slower. Need to make a spacer for the lead screw stub shaft as the one behind the screw gear is marked 24 and is too large for me to run 64 of the screw and a compound 20/64 above it to get it REAL slow. Anyone know its actual size?
Also I found some contact details of a lovely guy by the name of Michael Kurn who has agreed to send me the actual parts to repair my reversing box.
I’m amazed no-one spotted that my sliding gear yoke is home made from my previous pics unless mine is an earlier version.

Anyone spot the difference?

maybe @wa5cab may be able to use the drawing behind the part for the drawing repository in here? It could easily be redrawn.

 

[wa5cab]

Drawings are always welcome.

We do not have the drawing for the 9-116A spacer because last time that I checked, it was still available from Clausing. But if you look at your 9-101-20A 20T gear and visualize it with all of it's teeth cut off, you would be pretty close. As I mentioned a day or three ago, anyone with any gears that are scrap because of broken or worn-out teeth should not throw them away as the 9-116A is often among the MIA's when someone buys one of these lathes.

 

[Exuptoy]

I have quite a few 20’s and could use one but I think I’ll just turn one and get my mate to spark erode the keyway. The 24 does indeed look like the 24 without its teeth but as it didn’t look like Zamak I dismissed it.

 

[wa5cab]

OK. I don't know whether 9-116A is cast or machined. I had always assumed that it was cast.

 

[Exuptoy]

By the way you mentioned the other day that in back gear the torque should have been greater......

it was my fault, I assumed that backgear was just removing the bull gear pin, until I removed the upper cast covers I found the free wheeling gears with the lever in the end!! It does indeed have plenty of torque! Where’s the embarrassed icon

 

[wa5cab]

I always use the or the

 

[wa5cab]

One other thing:

If you engage the back gears without pulling out the direct drive pin, you lock up the spindle. The MOLO says to do this for routine chuck removal. Just don't forget and leave the spindle locked afterwards and start the motor. However, I would NOT use this method to lock the spindle if you are trying to remove a stuck chuck. For example on a new to you machine that may not have had the chuck removed for eons.

 

[Exuptoy]

I’ve had the chuck off this since purchasing. Changed it for the Burnerd 4 jaw, clocked a Kawasaki rear hub and dressed the faces. First time ever so was pretty pleased with myself.

 

[wa5cab]

OK. Sounds as though you've already gotten some useful work out of it.