Older used endmill will not fit new endmill holder;

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ome

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Hi guys,
what is the best way to get a stubborn endmill into a new endmil holder.
They are a 3/4 " shank and a 1.25" shank used that seem to have no burrs.
Can i use a wire wheel on the grinder or use a 3m pad red or green?
thanks,
Jon
 
Jon,

Do an inspection to make sure there are no dings at the mouth of the endmill holder and double check there are no burrs on the endmill. Make sure both parts are stabilized at the same room temperature.

After that, put a muslin polishing wheel on your bench grinder and a very light amount of fine polishing grit. (Being careful to not cut your fingers) polish the shank of the endmill. You might have to let it cool off before trying to fit it.

If you touch a grinding wheel to the shank, I can all but guarantee you'll ruin it.


Ray
 
Ray C said:
Jon,

Do an inspection to make sure there are no dings at the mouth of the endmill holder and double check there are no burrs on the endmill. Make sure both parts are stabilized at the same room temperature.

After that, put a muslin polishing wheel on your bench grinder and a very light amount of fine polishing grit. (Being careful to not cut your fingers) polish the shank of the endmill. You might have to let it cool off before trying to fit it.

If you touch a grinding wheel to the shank, I can all but guarantee you'll ruin it.

Ray
Click to expand...


Thanks Ray,
will a wire wheel ruin it as well? For the muslin, better to use the faster speed grinder.?
3450 rpm.
How do i clean or polish the endmill holders, they are R-8 endmill holders.


thank you , in advance for all the info that you share.
Jon
 
If there are no burrs, try a simple ball hone on a drill, it will take a few tenths off the inside of the holder with little effort. Tim
 
I had a new end mill holder that just would not take a 1" endmill shank. Must have been a tenth too small. I had no real way of dealing with it properly at the time. No tool post grinder. I said the heck with it and just chucked the blasted thing up,backed away the set screw,and took a very light pass with a carbide boring bar. Just VERY luckily,it happened to work perfectly!! I was simply lucky that the dust I cut out of the hole with the carbide boring bar was exactly enough to make it work!!

I don't advise you try this. I was just disgusted with the holder at that time,and did not care if I ruined it. Strictly good luck. The silly thing even ran true!
 
Last edited:
george wilson said:
Strictly good luck. The silly thing even ran true!
Click to expand...

I'm not so sure about that being a matter of luck - you may have luck, but it's quite clear you have the skill, and skill sometimes masquerades as good luck. The more we do and the better we get at our craft the better our luck, I think. We just don't make those old mistakes even though we're unaware of even thinking about some details.

Truing things on the mill is a great way to keep concentric. I always take the final pass on the mill rather than the lathe when I'm making a slotting saw or other arbor. It's the only way I can do the job without spending all day with dial indicators and micrometers. Just made a dedicated R8 stub arbor for small cutters with 5/8" holes. Even working between centers on the lathe, I didn't have the confidence I'd get it right, but by mounting it in the mill quill and using my AXA tool holder in the mill vise, I had no problem at all getting things right on.
 
I'm just not sure about a wire wheel so, in using that... Caveat Emptor...

When you want to take tenths off (or fractional parts thereof) polishing wheels are the way to go. As for the bore in the endmill holder, I wouldn't mess with that until you discover that several other endmills won't fit. That's a pretty good case stating the endmill is at fault. Anyhow, same deal... Take a wooden stick, chuck it in a drill chuck, wrap some cloth on the end, slather it with grinding compound and have at it. Go easy, rinse it well, let it cool to room temp and test the fit. Repeat until it fits.

Ray



ome said:
Thanks Ray,
will a wire wheel ruin it as well? For the muslin, better to use the faster speed grinder.?
3450 rpm.
How do i clean or polish the endmill holders, they are R-8 endmill holders.


thank you , in advance for all the info that you share.
Jon
Click to expand...
 
Maybe consider using a brake hone? Actually if it's "new" and isn't within spec I'd look to return it and get one that was properly sized.

JMHO

-Ron
 
Hmm -- no matter what you do it has to be accurate. The wire wheel won't be. The brake hone sounds best. It won't take much. Also remember when you make the tight ones fit all others will be loose.

"Billy G"
 
ome said:
Hi guys,
what is the best way to get a stubborn endmill into a new endmil holder.
They are a 3/4 " shank and a 1.25" shank used that seem to have no burrs.
Can i use a wire wheel on the grinder or use a 3m pad red or green?
thanks,
Jon
Click to expand...

It may also be the protective finish is too thick inside the bore. If so I would use a high speed drill and a abrasive pad to clean it. Good luck
 
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