how to make good fit?

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dontrinko

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I have a 10mm rod that I want to fit into a 10mm hole. The rod is ever so slightly to large. What is the best way to take a tiny (less than .001") controlled amount off the rod? Thanks; don
 
At that point, I would put in the lathe and take off material with a file. You can probably file and test fit
and repeat a few times until you have a fit to your liking. Sometimes for removing small amounts, one can
finish off with a flat diamond hone similar to filing on the lathe for a very smooth surface.
 
Grinding, such as surface grinder with spin fixture, or cylindrical grinder, both accurate to .0002 possibly better.
Sanding for a quicky.
Lapping if you want it real close.
Google external lap.
 
dontrinko said:
I have a 10mm rod that I want to fit into a 10mm hole. The rod is ever so slightly to large. What is the best way to take a tiny (less than .001") controlled amount off the rod? Thanks; don
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What kind of fit; loose slip, tight slip, light press, heavy press? What material?

It is difficult to get a proper fit with a rod and a hole when the rod is oversize without taking it too far. I have a set of gage pins that I use to determine the size of the bore so I can get to within a thousandth of the desired size. Past that, I will usually use light sanding accompanied by frequent checks for fit.

If you don't have gage pins, you can turn one or two test pins slightly smaller than your rod and use them to assess the hole size. You can also turn a very slight taper and use the depth of insertion to determine the bore size. Use a good micrometer for comparison of the test pin to your work shaft.
 
The hole is in the tail stock of a mini lathe. The rod is titanium. I want a good hand fit with no slop but so I can remove it easily. Don
 
Could you mount one of those diamond dressers for grinding wheels, the T-shaped ones, in your tool post and use the compound to do a controlled feed into the work piece?You're getting into the tool post grinder territory but this might be an alternative.
 
I've never worked with titanium, but for steel I would polish it in a lathe with a fairly fine aluminum oxide paper. Remember that polishing like this will heat the rod up some making it expand, so you might have to cool it off for accurate measurements. I've found that the first .001" or so comes off fairly quickly even in steel so check the diameter often when first starting until you get a feel for how quickly the material is being removed.

Ted
 
I polish spinning in the lathe. with 220 grit emery and ice it while it is spinning till it gets cold and check fit often.
 
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