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Tony Ennis
05-07-2010, 09:53 PM
There is apparently no limit to the abuse performed by my lathe's previous owner.

While fitting the AXA toolpost on I took the cross slide and compound apart. The bolts holding the compound in position had been turned to a point. The points did what you see in these images.

Nice one, Einstein (http://www.facebook.com/photo.php?pid=368224&l=140a66c9c3&id=1834210101)

I'm not sure the conic is removable. How should I repair this? I'm leaning towards filling the divots with JB Weld and filing it smooth. Then I'll make proper... thingies ... that can be driven against the conic.

Any other ideas?

wierdscience
05-07-2010, 10:02 PM
Bummer,don't think the JB will work,brass brazing might followed by some careful file work.

darryl
05-07-2010, 10:22 PM
Can that conic stand being enlarged by say .050 on its surface? If that is something agreeable to the mechanics of that assembly, then you could jb weld a shim all around, which will curve over all the divots and make them disappear. Of course this shim is going to be arc-shaped, and you would have to generate the proper curve in some sheet steel to make that out of. Essentially, you wind up with a fresh surface, with the diameter being a bit larger, but the angle unchanged. Just an idea.

lazlo
05-07-2010, 10:32 PM
you could jb weld a shim all around, which will curve over all the divots and make them disappear. Of course this shim is going to be arc-shaped, and you would have to generate the proper curve in some sheet steel to make that out of.

Welding a steel shim to dirty, old cast iron. Shudder.

I'd try Darin's idea of brazing it. Make sure to preheat and slowly cool it -- you only get one chance...

Carld
05-07-2010, 10:53 PM
A good TIG welder could fix it right up using soft Ni Cad rod without the flux. Preheating and cooling slow is the tricky part.

panofish
05-07-2010, 10:55 PM
I second the brazing idea!

Brazing is way easier than many think... it just takes patience for the metal to get to temperature. The end result will be almost as hard as the main metal. Of course you'll need to find another lathe to turn, reshape and clean the excess metal created by brazing.

form_change
05-07-2010, 10:56 PM
If the divots are not too deep, could you do a light skim and make up slightly longer brass thingys?

Michael

tyrone shewlaces
05-07-2010, 11:38 PM
I had an Atlas (waaaaay back) with a similar compound mount and similar issues with it. I can't remember now exactly, but I think on the Atlas it was a bolt-on affair which would be easy to remove/replace. Either that or I just don't remember milling it off.

At any rate, I turned my own replacement and case-hardened the crap out of it. The new one sure worked tons better than the original.

You could look it over and see if there's clearance there or enough metal to counterbore for a nut or bolt head on the backside so things don't go bump. I'd much rather make a replacement and fit it than try brazing, epoxy, welding or any of that. The spud itself is easy to make. Mill the old one off and turn or mill a recess to locate the new one (a light press fit might help here). Using two or three bolts to attach it might be more stable (i.e. less prone to spin loose or something) than one bolt/nut in the center. Any kind of steel will be better than what you've got there, and harder steel will last longer if you have any around.

Just another option to chew on.

J Tiers
05-08-2010, 12:31 AM
It looks as if the divots are small enough that a proper angled brass wedge would bridge over them...

have you tried just making the brass parts and using it?

I don't like the idea of trying to braze it up, or Ni rod it, etc, might mess up and warp the whole crosslide. That would get you in a lot of trouble you don't want.

Another option is what I think was suggested.... mill that damaged part off and put in a steel replacement. You might still need to touch up the scraping, but it seems as if that would be less likely to do bigger damage.

Black_Moons
05-08-2010, 02:02 AM
Milling it off and bolting a turned replacement back in with something like 4 counterbored SHCS to keep it from rotating (and allow ease of shiming underneath) might do the trick nicely, with little chance of distortion. Could turn the replacement part before you mill the chunk off your lathe.

.RC.
05-08-2010, 02:59 AM
That is nothing, on one of my lathes one of the previous owners ripped the entire compound slide off the cross slide... And this a 4300lb 17" lathe..

alcova
05-08-2010, 06:19 AM
What kind of lathe and what part is it...I pretty sure I have a base to SB 9" Compound somewhere

Walt

JCHannum
05-08-2010, 07:49 AM
It looks as if the divots are small enough that a proper angled brass wedge would bridge over them...

have you tried just making the brass parts and using it?

I don't like the idea of trying to braze it up, or Ni rod it, etc, might mess up and warp the whole crosslide. That would get you in a lot of trouble you don't want.

Another option is what I think was suggested.... mill that damaged part off and put in a steel replacement. You might still need to touch up the scraping, but it seems as if that would be less likely to do bigger damage.

I agree with Jerry. Except that I would use case hardened steel tapered pins for the locking pins. This is what the original items were. They will be wide enough to bridge the goobers and lock the compound in place. Brass or softer pins can deform from the indentations and be difficult to move.

Tony Ennis
05-08-2010, 08:03 AM
alcova, it's a Craftsman 12".

There are some good ideas here. I don't weld so those options are less attractive. Machining the whole thing off is an idea. I double-checked and this one is permanent. I can't imagine it was machined on the compound but who knows. There's a hole in the top, I'd be surprised if it weren't pressed on.

I was thinking of JB Welding the divots so a brass pin wouldn't be embossed and otherwise boogered.

I found one or two compounds on ebay too. A/C parts are getting expensive now - far more than they were last I looked, about 2 years ago.

The locking pins are beveled to match the conic of course, but do they also have an arc in them? When doing maintenance, how does one remove the locking pins which are at the bottom of a hole?

Carld
05-08-2010, 08:18 AM
Tony, I don't think the original pins were brass. It's been a long time since I took a compound off but the best I can remember they were steel and could be removed with a magnet. I think all I ever did was wobble the compound around as I lifted it off to work the pins back into the holes.

I wouldn't use brass and they don't need a radius on the bevel.

J Tiers
05-08-2010, 08:57 AM
I never had one like that, so I assumed that brass was as stated, the known material.

If the originals weren't brass, don't use brass.

polepenhollow
05-08-2010, 09:17 AM
Make a brass sleeve, taper inside, straight outside, 360 Degrees. Split it, clamp on the brass sleeve w/ your screw.
K Lively

Hot Bob
05-08-2010, 09:29 AM
A good TIG welder could fix it right up using soft Ni Cad rod without the flux. Preheating and cooling slow is the tricky part.

I'm a very good TIG welder and I wouldn't do it. Cast iron is just too unpredictable. I like the idea of cutting it off and attaching a new piece.

Bob

gzig5
05-08-2010, 11:33 AM
I'm a very good TIG welder and I wouldn't do it. Cast iron is just too unpredictable. I like the idea of cutting it off and attaching a new piece.

Bob

On my 12" Craftsman, the pins were steel. I don't think they were hardened but they were sufficiently reduced on the end diameter to easily clear the minor diameter of the hole should they mushroom. Milling the radius of the dovetail into the ends of the pins would be desirable, but require more setup than just lopping them off at an angle.

I agree with the others who have suggested a replacing the dovtail. I would suggest turning off the damaged part plus 1/4"+ each side leaving a post/tenon on the compound. Before doing that, make the new dovetail ring from cast iron or steel with the desired tenon diameter through hole. Sneak up on the tenon diameter so it will be a light press fit. Heat the ring (~250 should be fine) and drop it/press it on the tenon. Put the assembly in the mill and at the joint line drill two holes 180 degrees apart for pressed in pins. Then install four bolts through the ring part into the base. You could also loctite it on forgoing the bolts and pins and it would probably never move.

There are lots of spare parts for these out there but they are increasing in price. The problem is that you don't know what condition the dovetails on the used replacement are and you could be worse off than when you started.

gwilson
05-08-2010, 02:36 PM
This may be a stupid idea,but can you just take the top slide off,turn it 180 degrees,and put it back on? Then the divots won't be on the side you are using. I don't recall if those old Atlas/Craftsman slides were symmetrical so they might be reversed.

Peter.
05-08-2010, 03:07 PM
Why not just turn the taper deeper only in the damaged area where the wedges touch? You'll keep the thickness at the base of it so the strength is not reduced.

Tony Ennis
05-09-2010, 10:02 PM
I doinked in the shop today. Here are the abominations the previous owner was ramming into the spud. Below are the replacement beveled parts I made this afternoon. Hopefully I'll be able to get by without any major reconstruction of the compound.

Tomorrow I'm off to the Home Center to get two replacement bolts. The kind without crude points on their ends. :rolleyes:

picture (http://www.facebook.com/photo.php?pid=370927&l=f172d318e3&id=1834210101)