I recently purchased a sherline 12" mini mill to go along with my atlas 12"x36" lathe. It only came with a mt1 drill chuck so I figured I would make an endmill holder to hold 3/8" shanked endmills. Not a big deal I figured? I have tried everything I can think of but all 5 of the ones I have turned (in materials from aluminum to mild steel) have been a no go. I am turning the ID, shank holder, OD, and single pointing the threads without removing the piece from the lathe. The final operation tonight was to take the part with finished threads, mount it to the mill, rotate the head of the mill 90 deg and bring the shank holder section to .370" with a boring bar mounted to the mill bed. I then removed the part and hand reamed the final ID.
The OD when mounted to the mill will spin within .001" or under every time. The problem is that the endmill is spinning within .001" at the base of the shank but appears to be crooked at the end of the cutter flutes??? This is verified when taking a 5/16" endmill and making a pass, then measuring the width of the slot. it is usually .325" or slightly more.
I am baffled by this and could use a 2nd set of eyes or ideas on what I am doing wrong when making this part. It is visually crokked when spinning by hand. The OD of the part is dead nuts from one end to the other.
The OD when mounted to the mill will spin within .001" or under every time. The problem is that the endmill is spinning within .001" at the base of the shank but appears to be crooked at the end of the cutter flutes??? This is verified when taking a 5/16" endmill and making a pass, then measuring the width of the slot. it is usually .325" or slightly more.
I am baffled by this and could use a 2nd set of eyes or ideas on what I am doing wrong when making this part. It is visually crokked when spinning by hand. The OD of the part is dead nuts from one end to the other.