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gzig5
01-19-2007, 03:08 AM
Does anyone have a drawing of the little Zamak gearbox in the apron of the Atlas/Craftsman lathe that tranlates the handwheel to the rack gear? Or does someone have a decent one they could measure or I could borrow to make a print from? Mine is pretty well shot with .040" play on the shaft and I am afraid it is about to break as well. I am afraid if I take the gears off the shaft to measure it, I won't be able to get it to hold together while using the lathe to make the new parts. I tried asking on the Yahoo site but didn't get any nibbles.
I would be glad to share the fruits of my labor (if it works) when done. I plan on making it out of a block of 6061 and use bronze bushings on the shaft. The gears will probably be keyed onto the shaft, rather than broached square.
Greg

dicks42000
01-19-2007, 04:32 AM
Gzig;
What size Atlas lathe are you playing with?
I have a 618....can take pics & measurements if necessary.
Surprised that you didn't get any of the guru's on either the 618 website or the general Atlas/Craftsman website to reply.
Good luck.
Rick

wirewrkr
01-19-2007, 10:45 AM
If it's for a 10", I've got an extra one that's cracked. I can send it to you if you want and you can evaluate it. If you decide to make some, I'll get in line as the one currently on my 10-f is pretty worn. Last time I checked these were still available from Clausing but were pretty pricey. About $75.00 if I remember correctly. If you can make them a little cheaper out of aluminum, you will have a very captive audience to sell to.
Robert

gzig5
01-19-2007, 10:46 AM
Rick,
Oops, I guess that would be pertinent information. It is a 12" Craftsman, but the 10" Atlas' use the same part.
If I don't have any luck here, I may try on Yahoo again. I think those guys get distracted easily.
Thanks for the offer.
Greg

GRH
01-19-2007, 10:56 AM
Did you try to get a new one from Atlas, I have found if they cannot supply they will sell for about $5.00 a copy of their drawing (a handling cost).
You have better luck with a phone call to them in Elkhart Indiana, and always give them the part #.

Regards
Graeme

CCWKen
01-19-2007, 11:35 AM
I'm on the way out the door right now but if you can wait until this evening, I'll shoot pics and measure. I've got one off a 12" that has one of the mounting tabs broken. (A common problem)

Later

ronm
01-19-2007, 12:47 PM
These things show up on ebay once in a while, I haven't checked lately. I started out once to do what you say, make one from the solid, got sidetracked, & then came across some Al welding rod that was supposed to fix anything, & guess what? It stuck the gearbox back together...the mounting foot was broken. So far it has held, now that I refrain from the act that broke it in the first place-using the carriage to try to cut serrations on a shaft...don't do this w/an atlas/craftsman! I still remember that sickening "snap"..."Real" lathes can do that, our little A/C's can't..
I suspect if you work up a copy, there will be a market for it. In the time I hung out on the A/C Yahoo group, this was a recurring subject.
Ron in CO...

gzig5
01-19-2007, 01:34 PM
Ken,
That would be great if you could send pics and measurements. If I can keep the post office out of this all the better. I am not in a big hurry, but I do want to get a couple things fixed on the lathe before I take on a couple projects I have in mind. I think the critical dimension that is hard to get out of an assembled unit is the relationship of the shaft bore to the mounting slots and the clearance required on the shaft to clear the lead screw. If you have a shaft to measure, I'd be interested in that as well.

When I got the lathe a couple years ago, the cross slide nut was worn out (and still is, but I now have the material to make a new nut and screw) and I recoiled at the prices Clausing wants. I thought I'd make new ones and a couple extra to sell on ebay. Now everybody and their brother is making the nuts. I'll have to see how hard it is to make the gearbox body accurately, before I consider selling them. With family and work duties, my project list gets longer and longer. Even if I could sell them for the same price as Clausing, I don't think it would be worth my time, making them on my manual machines. I will definitely share whatever comes out of this for others to make their own. Thanks.
Greg

bhjones
01-19-2007, 04:19 PM
Are you saying the part broke while you were using the power feed to knurl? I'm not clean on what you mean by "serrations".


So far it has held, now that I refrain from the act that broke it in the first place-using the carriage to try to cut serrations on a shaft...don't do this w/an atlas/craftsman! I still remember that sickening "snap"..."Real" lathes can do that, our little A/C's can't..

ronm
01-19-2007, 09:28 PM
Are you saying the part broke while you were using the power feed to knurl? I'm not clean on what you mean by "serrations".
Think "splines"...using the carriage feed to make a longitudal cut on a shaft w/o the spindle running, then index the spindle to the next spline. The little carriage feed gearbox on the Atlas won't handle that much stress. Sucks to find out the hard way.

CCWKen
01-19-2007, 09:38 PM
Hey Greg.

Well I took pictures but I'm trying to figure out how to go about measuring and linking to the pictures. Without actually drawing it, about the best I'll be able to do is add dimentions to the pictures. There's so many it may take me a while.

Just so we're talking about the same piece, is this it?

http://img.photobucket.com/albums/0903/CCWKen/Tools/Craftsman%20Lathe/Parts/TraverseGearCase.jpg

http://img.photobucket.com/albums/0903/CCWKen/Tools/Craftsman%20Lathe/Parts/2007_0119TransverseAssembly0009.jpg

gzig5
01-19-2007, 09:42 PM
Ken,
That's it. If you can take the shaft out and get running surface and shoulder dimensions, that would be a bonus.
Greg

bhjones
01-20-2007, 12:26 AM
Ah, I see. How much material were you trying to dig out per pass?


Think "splines"...using the carriage feed to make a longitudal cut on a shaft w/o the spindle running, then index the spindle to the next spline. The little carriage feed gearbox on the Atlas won't handle that much stress. Sucks to find out the hard way.

bhjones
01-20-2007, 12:41 AM
This part on my 10-f was replaced by a shop built part out of aluminum before I got the lathe (as was the tailstock end leadscrew support. It must have been ugly). I also have a Craftsman that was very rough when I picked it up and this part along with the miter gear post were rendered into small bits of metal buy some prior owner.

The screw simply passes through this part and all power transfer is either through the key in the miter running off the screw slot, or the halfnuts running on the threads.

As I've heard it, the weak link (intentionally weak i'm told) in the stock lathe was the screw support at the tailstock end. If the carriage hit an obstruction the support twisted off and the screw just turned.

What events cause the destruction of this part?

Also, if someone replaces the weaker Zamac parts with aluminum or steel, what's the next failure point?

ronm
01-20-2007, 01:43 AM
Ah, I see. How much material were you trying to dig out per pass?
Not much, really, not much more than upsetting the surface w/a threading tool laid on its side. I think I was trying to "rescue" a press fit situation that turned out a little loose-:o ...

ProGunOne
01-20-2007, 02:16 AM
I may have an extra you could borrow if you need it. LMK, Paul.