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View Full Version : Making a New Compound For a Lathe



Arbo
05-03-2004, 08:30 AM
It seems like I am constantly having to make a repair part for a machine. The compound on my Atlas 6X18 is showing some wear. The T-Slot is slowly disintigrating. When I got it, it had a few chips out of the cast iron, and it keeps getting worse. I would like to make a new one instead of buying one. I have the tooling, and the technology to do it, but was wondering if it would be OK to use CRS instead of a casting. Thanks in advance.

John Stevenson
05-03-2004, 08:45 AM
When I had a Myford ML7 I bought a long cross slide and screw for it from Myfords, this than gave me a spare screw off the old cross slide.
This was the same as the top slide one but about 1.5" longer.
I made a new longer top slide to make use of this screw and also to be able to quickly turn longer tapers without resorting to the taper turning attachment.
The Myford top slide can only 'just' do a No2 morse. With the longer top slide I was able to do MT3 comfortably.
The top slide was just a piece of flat steel of the cooking variety and had a rough dovetail milled in the bottom and the hole for the toolpost [ no slot on a Myford ] in the top.
I also took the oppertunity to put two tee slots in the top of slide in case I needed them for weird jobs but I can't remember using them. Probably would have been different if I hadn't had a mill.
The top was surface ground flat, turned over and the bottom surface ground and the last two licks put on the dovetails in case it had warped during the initial machining.

Fitted this with the usual gib strip and it never gave me a moments problem. I have since sold the machine but it's still fitted.

John S.

JCHannum
05-03-2004, 09:33 AM
No shame in using mild steel for a compound slide. Cast was probably used as much to reduce machining as any other reason.
Another method of repairing such wear is to machine off the top of the compound the thickness of the flange and replace with two pieces of steel fastened with flathead screws.

[This message has been edited by JCHannum (edited 05-03-2004).]

Forrest Addy
05-03-2004, 11:24 AM
You could look for a replacement compound for your lathe but there's likelyhood of it being not much better than the one that's causling you problems.

If you make your own, I suggest you use cast iron is you can. Many local steel suppliers offer Durabar and similar manufacturer's line of continuous cast iron products.

They will saw rectangular pieces to order. For a lathe like yours this might cost $50 or so but it will be the right stuff possibly superior to the original if you purchase one of the higher strength alloys.

Here's a link to Google search results for "Continuous cast iron".

http://www.google.com/search?hl=en&ie=ISO-8859-1&oe=ISO-8859-1&q=Continuous+cast+iron&btnG=Google+Search

Making the compound is a lathe and a mill job but you can make it all on the lathe with careful set up for the milling.

Such a small compound can be dressed up to look original South Bend parts particularly if you take time to distress the new surfaces to resemble the as-cast surfaces of the original parts.

I suggest you recycle the original gib. Everything will have to be scraped for final fitting. This is a small project that uses a lot fo skills. By the time you're finished with it your skill set will have grown immeasurably.