taking .002 to .003" off aluminum?

dontrinko

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I just got a Taig Lathe. For my 1st project I need to take .002 to .003" off an aluminum bar that is abought 1.25" in diameter and abought 7" long.
I am not experienced enough to know what the best way to do this is. Would I be best off using the lath to turn the piece and using emery cloth to take the metal off or should I try to remove the metal with a tool bit?
What speed should I use?
I have both carbide (C2) and HSS steel bits. Many years ago I made my own HSS bits but always with a round tip. Thanks; Don
 
Welcome to the forum, Don.

If the end product must be round, then you probably should turn it off. If the stock is "about" 1.25, as in extruded stock, it probably isn't all that round, so polishing it off would yield less than ideal results. On the other hand, if it is ground stock, and hence round, there shouldn't be a problem abrading it off. Just be careful of the expansion that heat will give it, if you spin it fast and get it hot. Might want to shoot for the high side of your tolerance in that case. If you can put it between centers, and your lathe runs true.....go ahead and cut it.

Oh, speed...with carbide, as fast as the lathe will run.
 
It has been turned down so it should be reasonably round. Thanks for all the suggestions. Don
 
Re: taking .002 to .003

The shear tool is ground across the end with a wide radius the entire width of the tool. There is end clearance the same as other lathe tools, and side rake about 45 degrees across the tool. It can be used to take finishing cuts and puts on a very finish. It should be honed to a very smooth, keen edge. Maximum cut is about 2 to 4 thousandths. Shear tools can be used in both lathes and shapers to the same advantage, a good finish. When properly ground the material is removed in tiny curls.

See: http://www.gadgetbuilder.com/VerticalShearBit.html
and http://www.neme-s.org/shapers/columns/shaper_column_43.html tool being used on a shaper.

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Got my project done today. I knew I needed practice and I'm glad I did.
Everything went well. I used a steady rest and was able to get the piece turned down for a good fit. I ended up taking .004" off. Thanks for all the suggestions. Don
 
you can run into so many problems trying to take off that little amount with a tool bit. tail stock not set right out of round part if a little out of round is ok then just use a file and emery cloth to get it to size may be the non purist way out but it will work and you get a finished part. if this doesn't sit well with you then blue the outside if the part and just try to machine the bluing off a little at a time measure often it can be done good luck ( Iwould just emery it down alum does this very fast and it comes out pretty.) bill
 
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