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greentowtruck
03-31-2009, 07:05 PM
Well I was playing around with my craftsman 12" lathe a couple days ago and had a tool bit dig into the work. when that happened I was running the power cross feed. I shut it down and backed out of the work the turned the lathe back on but the power cross feed quit working. I took apart the apron and found the key in the miter gear was sheared off. It wouldn't be a big deal but the key was part of the gear now I am trying to figure out a way to fix it. I don't have a mill yet or I would just machine a slot in the gear casting to take a key. Any ideas??

Thanks

Matt

John Stevenson
03-31-2009, 07:16 PM
Carefully file a new keyway, I believe these are diecast ? If so practice on a piece of aluminium first if you have no experience of doing this before.

.

J Tiers
03-31-2009, 08:53 PM
I think yours will look like these? The RH one is original, the left is shop-made. A new steel one was $120 two or three years ago.

http://img.photobucket.com/albums/0803/jstanley/newgear2.jpg

IIRC the key is cast, the whole works is a casting inside a steel sleeve. Mine was in the table lift for a large Atlas 18" drillpress, but its the lathe part, according to the part # I found, which IIRC was 10F-82A.

Filing a new keyway and inserting a key might be a problem, but may be do-able. There isn't a lot of "meat" in the zamak inside the steel sleeve, and you wouldn't want to cut clear through the zamak. Soldering may not be a good idea, but epoxy would work to hold in a key.

I don't know if drilling some holes and epoxying in pins in a line would be better... might weaken thigs less, but you also could use a shorter steel key.

sch
03-31-2009, 11:29 PM
I wonder if zamak gear is not a 'feature' rather than a bug. Ie it is
designed to be the weakest link to prevent something else less
forgiving from being trashed in this scenario. Variant on the plastic
drive gear in a lot of smaller lathes. Seems like a small boring bar and
shaped HS bit at right angles would make short work of a shallow
groove in the zamac that would locate an equally shallow key that
was tapped or epoxied into place. Just rack (hand crank) the boring bar back and
forth moving the table a few thousands each time. Works in steel,
should go snicker snack in zamak. Might be best not to make it
too stout.

greentowtruck
03-31-2009, 11:36 PM
yeah that looks like the gear...part # 10f-82 iirc only mine doesn't have the key anymore except a faint line where it used to be almost looks like it was bored out. I have located one on fleabay though hopefully I can get that one then work out a fix for the old one.

dp
03-31-2009, 11:53 PM
yeah that looks like the gear...part # 10f-82 iirc only mine doesn't have the key anymore except a faint line where it used to be almost looks like it was bored out

If that's all that is wrong then the suds pumper is right - make a new keyway and put it back together. A die filer, a file, a shaper, what ever, should work. It would be a good time to have a shop made keyway cutter :)

http://homepage3.nifty.com/amigos/slotter/slotting_tool-e.htm

tdkkart
04-01-2009, 01:39 AM
Or you could just buy one.........

http://cgi.ebay.com/ATLAS-CRAFTSMAN-LATHE-APRON-BEARING-HOUSING-MITRE-GEAR_W0QQitemZ150335501842QQcmdZViewItemQQptZLH_De faultDomain_0?hash=item150335501842&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A0%7C293%3A2%7C294%3A50

http://cgi.ebay.com/ATLAS-10-LATHE-CARRIAGE-APRON-CROSS-FEED-MITRE-GEAR_W0QQitemZ220386212750QQcmdZViewItemQQptZLH_De faultDomain_0?hash=item220386212750&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A0%7C293%3A5%7C294%3A50

In any given week you can pretty much build an Atlas lathe off Ebay.

doctor demo
04-01-2009, 01:57 AM
found the key in the miter gear was sheared off. It wouldn't be a big deal but the key was part of the gear now I am trying to figure out a way to fix it. I don't have a mill yet or I would just machine a slot in the gear casting to take a key. Any ideas??

Thanks

Matt
Matt I'm not sure how You would machine a slot in the gear with a milling machine any easier than with Your lathe.
If You chuck up the gear in the lathe You can cut a keyway with a boring bar . Grind a tool bit the proper size of the key and put it in a boring bar and run the bar into the gear a few thou. at a time untill You get the proper depth . Put the lathe in direct and back gear at the same time so the chuck will not move , then run the carrage back and forth by hand.
Hope this makes sense to You , it is perfectly clear in" My head ":eek: .

Steve

knedvecki
04-01-2009, 10:26 AM
Like SCH and Doctor Demo said. Works GREAT!!!!

TGTool
04-01-2009, 11:11 AM
You can make a tool for a QC toolpost like this one which does graduation lines on dials ...

http://i48.photobucket.com/albums/f244/TGTool/EngraveAttach.jpg

or can have a tool for cutting keyways.

http://i48.photobucket.com/albums/f244/TGTool/KeyCut1.jpg

aboard_epsilon
04-01-2009, 11:31 AM
if your not up to it ..you could always solder it on ...put just enough on ..so it would fail if you got in the same situation again .

all the best.markj

RPease
04-01-2009, 01:48 PM
Or you could just buy one.........



In any given week you can pretty much build an Atlas lathe off Ebay.

Yeah...........for maybe 10 times what it's worth.....LOL :D