Modifying a end mill holder

Hi Video_Man

I bought an economical 3/4in end mill holder today to experiment with, and hopefully modify like you did yours. It looks very much like yours.

The first thing I did was drag a file across the beveled nose and was surprised at how soft it is. I don't think there will be any issue cutting the bevel off.

Did you simply chuck the end mill holder in your lathe chuck? Would it be beneficial to insert a length of 3/4in round stock in the end mill holder and capture it between the lathe chuck and tail stock for add stability and trueness?
 
I just chucked it in the 3-jaw on the big end. It's plenty sturdy, no need for any additional metal. And, because you're just whacking a hunk of the end off, as long as it is centered in the chuck, there's no trueness involved (as there might be if you were turning the diameter). And the tailstock would just get in the way. Keep your overhang reasonably short and should be no worries.
 
I worked on modifying the end mill holder with mixed results.

I was indeed successful at cutting the beveled nose down so that the flat on the annular cutter reached the set screw, but the 16mm set screw is way too big to engage the 12mm wide flat on the cutter properly. More on that later.

The beveled nose of the holder was fairly soft, at least until I got closer to the main barrel. The closer I got the harder it got. I burned out at least one, possibly two cheap brazed carbide cutters on the cut. Cheap Chinese carbide cutters on a cheap Chinese end mill holder. Some poetic justice there.

It left quite a burr on both the ID of the hole and OD of the barrel. My tool holders are 5/8in wide and I had a little trouble reaching the bur inside the 3/4in bore before rubbing on the tool holder. Ended up using a Dremel and a small tapered stone to complete the chamfer.

Now, I'll attempt to shape the end of the set screw to engage the flat on the annular cutter properly. Not sure yet how to hold the short screw in the lathe chuck well enough. I'll probably buy several to have in the attempt.

Pics below:

Turning end_mill_holder.jpg

Set screw too big.jpg

Set screw too big2.jpgSet screw too big2.jpg
 
Yes, I see there's a problem. My cutters have a longer flat that clears the setscrew and my screw has a small 45 deg. taper on the last couple of threads, so this didn't arise in my case. One way to chuck the screw, if you happen to have a hex drive socket (Allen-socket, some call it) that fits the set screw hole, is to chuck the socket, attach the screw, and retain the right end with your tailstock center. Looks like you need to turn a spigot on the end of the screw...which is probably hardened. Nothing is ever easy! I suppose you could substitute a 16mm x 1.5 cap screw or bolt and shorten it to fit, might turn easier...best wishes!
 
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For what it’s worth I also bought the Accusize 3/4” Weldon adapter to use annular cutters in my mill. It works fine for me

488d83161d8c2ff76b1fead84982a899.plist
 
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