Cutting down chipped end mills?

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Zoltan

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So I now have a collection of 4 flute end mills on which a corner or two have been chipped. I figured I should be able to cut or grind the end mill shorter to get to the fresh cutting edge and keep on using them (obviously they wouldn't be center cutting).

Is there any easy way to do this, or a cheap place to send them to get it done?
 
I save end mills like that for other jobs. Like when I need an angle or radius…Dave
 
We use those for side cutting.

Say you have a chunk of something cut with band saw that needs good edge.

Place in mill and use the higher part of end mill to true it up.



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I use them for HSS tooling in the lathe. Learned that from a machinist. They make great boring bars, it does require a lot of reshaping but can be quickly accomplished using a hand held grinder and a cutting disc.
 
For end mills where they have a small chip or have dulled, I will grind a small radius on the tips. Make sure to provide relief as you would on a lathe tool. Try to grind all the flutes to the same radius. The regrind will often give a better surface finish than a new end mill.
 
A chipped corner can be turned into a radius on all the flutes. Carried further, it can be made into a ball end mill. I have quite a few of those I picked up used, radiused in a fixture and relieved by hand. They work well. The rounded corner ones are good for hogging material, and then using another end mill to finish the corner if needed. A mill with one chipped corner can also just be used as it is, on the side, or even on the end. It does not change the surface finish as much as you might guess. I got some slitting saws in tool lots that have a tooth or two missing. I can hear the missing teeth in the cut, but cannot see it on the finished work. The cutter will have a heavier load on the tooth or flute following the chipped or broken one, so it must not be used as aggressively as a new and perfect cutter. Use 'em up!
 
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Lots of very good suggestions already been offered above. But, to tell you the truth, I've used end mills even with bad corner breaks and just feed them a bit slower.... Just think of it as a 3 flute end mill instead of 4. YMMV, but I do it all the time. If something needs a very fine finish I'll will switch over to a good cornered M42 or similar. It all depends on what you're using it for.

Ted
 
Here's a cheapie Chinese $3 1/2" end mill I've been using for a few weeks now roughing several pieces I've been working on. 20170928_112457.jpg

YMMV,
Ted
 
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