Atlas Pick-O-Matic Drive Gear 10-1213

[Blue]

Does anyone know the specs on the Atlas Pick-O-Matic drive gear 10-1213? (Or where I can find one?)

At some point in its life, someone removed the drive gear, leadscrew and all change gears from my newly acquired TH48. Otherwise, everything else appears to be entirely in tact. I am assuming that I will likely need to make one, or find an off-the-shelf gear and adapt it to accept the keyed leadscrew properly. If I do need to make one, having the dimensions/sketch with the dimensions, tooth count, etc. would be extremely helpful.

Holding off on getting a replacement leadscrew until this mystery is solved. Especially since the manual suggests that the head-end of the leadscrew needs to be cut off at the shoulder.

Thanks,
Blue


Mods/Admins - I originally posted this here: https://www.hobby-machinist.com/threads/atlas-pick-o-matic-drive-gear.99322/ Please delete as appropriate.

NOTE to Blue - As there was only one reply and as deleting the thread would have deleted post-counts from you and responder, I elected to edit thread title with re-direct instead of deleting thread.

Robert D/WA5CAB Moderator

 

[shadetreedad]

Blue,

I have a spare Pick-O-Matic gearbox. Over the weekend I could take it apart for dimensions. And/or send the gear to you for a pattern. Then when you're done you could send it back. Pretty sure that is the only gear in the gearbox that is made of ZAMAK.

Mike

 

[Blue]

Thanks Mike! Still trying to wrap my head around "spare Pick-O-Matic gearbox"! Based on my limited research, is seems like the Pick-O-Matic sort of a stop-gap between nothing and a real gearbox(?)

Any idea why the drive gear would be ZAMAK? I assume it is to intentionally be the weakest link to self-destruct in case something really jams up? If so, a 3D printed gear might actually be ideal for the replacement

We can start with a sketch/dimensions (and maybe pictures?) and see if I can do something with that. With the dimensions, I can sketch it up in 3D Cad and print one, especially if it is intended to be sacrificial. If that does not work out, then I'll take you up on your offer to borrow the spare.

Sounds like I can get going on acquiring a leadscrew..

Thanks again!
~Blue

 

[shadetreedad]

Blue,

Yea, it was sort of a stop-gap box. They were made from 1943 into 1946. I really like mine. Normally I run gearing through a banjo with the final leadscrew gearing ~ A= 0.004, B= 0.008, C=0.002. With this setup there is always a “perfect” speed. The only time I change gears is for threading. I don’t think the ZAMAK gear is for a weakest/sacrificial link as the ZAMAK leadscrew support bearing on the right end of the lathe is actually for that purpose. With that said however, what typically fails on those gears is the built-in keyway. It will eventually round off. On mine, I added an aluminum adapter between the gear and leadscrew with a shear pin so it will fail before either end has a chance to break.

And my guess is a 3D printed gear would work very well.

Anyway, I'll have those dimensions/pictures to you early next week.



Mike

 

[benmychree]

Sacrificial lead screw support? been there, done that back in the early 60s on a friend's father's lathe, got a part and fixed it, no hard feelings.

 

[Blue]

Anyway, I'll have those dimensions/pictures to you early next week.

Thanks Mike! That will be much appreciated! I will likely need more advice and info on the Pick-O-Matic. I know I do not have the change gears and had already planned on printing the set, but as I look closer, it appears that there may be a few more things missing besides the gears (like the drive gear)... The 3 posts are there, but no in/out gear or knob. Looking at the exploded parts diagram, it would appear that I need bushings, screws, hold-down bracket, the knob, etc. All should be relatively to buy or make, but lack of dimensions might be a challenge. At least they left the complete tumbler assembly intact. I will work on posting a few pictures in the next day or two.

@benmychree - Over time, I have found a few things to be sacrificial... that probably should not have been. Glad you were able to replace and fix it!

 

[benmychree]

Thanks Mike! That will be much appreciated! I will likely need more advice and info on the Pick-O-Matic. I know I do not have the change gears and had already planned on printing the set, but as I look closer, it appears that there may be a few more things missing besides the gears (like the drive gear)... The 3 posts are there, but no in/out gear or knob. Looking at the exploded parts diagram, it would appear that I need bushings, screws, hold-down bracket, the knob, etc. All should be relatively to buy or make, but lack of dimensions might be a challenge. At least they left the complete tumbler assembly intact. I will work on posting a few pictures in the next day or two.

@benmychree - Over time, I have found a few things to be sacrificial... that probably should not have been. Glad you were able to replace and fix it!

Likely, if I was unable to fix it, I likely would have been less welcome at their shop and home.

 

[benmychree]

Thanks Mike! That will be much appreciated! I will likely need more advice and info on the Pick-O-Matic. I know I do not have the change gears and had already planned on printing the set, but as I look closer, it appears that there may be a few more things missing besides the gears (like the drive gear)... The 3 posts are there, but no in/out gear or knob. Looking at the exploded parts diagram, it would appear that I need bushings, screws, hold-down bracket, the knob, etc. All should be relatively to buy or make, but lack of dimensions might be a challenge. At least they left the complete tumbler assembly intact. I will work on posting a few pictures in the next day or two.

@benmychree - Over time, I have found a few things to be sacrificial... that probably should not have been. Glad you were able to replace and fix it!

Likely, if I was unable to fix it, I likely would have been less welcome at their shop

 

[shadetreedad]

Blue,

The gear is removed from the gearbox. And the first thing to say is I was wrong about it being ZAMAK. It is steel just like all the other gears in the gearbox. When I first looked at the gear it appeared that the teeth were very worn where they engage. Turns out that is just the way it is made. Plus, the built-in key is “punched” from the outside which gives the appearance of cast key in ZAMAK. Anyway, it certainly should be easy to duplicate. It has the exact same profile as a 20 tooth change gear. So, one of those could be used with a custom shaft to mate up with the lead screw. That’s how I'd make one. I think all the pertinent photos/measurements are attached. If you need any more just let me know.

All the best,

Mike

 

[Blue]

Thanks Mike! These pictures are great. I started pulling off my pick-o-matic this weekend, but due to time constraints did not get very far. I know for sure it needs to be de-grimed inside. Hopefully, the disassembly will give me an idea how to install this and if anything else is missing. I suppose the good thing is, that it is indeed the same as a 20-tooth change gear, and I have an un-modified leadscrew on the way. Since it will be un-modified, I can tailor modify it to suit a 20-tooth gear instead of just hacking it off at the shoulder, per the manual.

Would you mind taking pictures of the install/remove steps for the drive gear into the gearbox? I suppose it could be obvious when I take off the box, but having more info = more comfort/confidence when doing something new. This lathe restoration is a whole new adventure for me.

Thanks again!
Blue