Author Topic: School me on annular cutters for milling machine  (Read 1053 times)

Offline Jasonb

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Re: School me on annular cutters for milling machine
« Reply #15 on: January 14, 2022, 07:07:40 AM »
For those not looking at other forums it may be worth pointing out that the usual R8 and MT sidelock holders have the grub screw a lot further from the end so it does not easily sit on the cutters shank, Also the proper holder has two grub screws at 90deg as many cutters have two flats unlike the single flat on a milling cutter.

You also get the ctr pin hole if you want o use that.

Offline Brian Rupnow

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Re: School me on annular cutters for milling machine
« Reply #16 on: January 14, 2022, 09:08:37 PM »
I couldn't figure out why the correct R8 holder for these annular cutters cost $75, while a standard R8 holder for a 3/4" drill was only $31. Now that I have the parts here, I see that there is a spring and a snap ring inside the correct R8 holder that lets a centering-pin retract into the body of the holder as the annular cutter passes thru the plate you are cutting. The centering pin then becomes spring loaded and pushes the "slug" out of the annular cutter after your cut so you don't have to fish for it with a pair of pliers. You can see the end of the centering pin sticking out past the face of the cutter. You can also see a centering pin setting beside the cutter---I made that one .001" undersize, which normally wouldn't matter, but in this case the pointy end is cantilevered out so far from where it is held that with 0.001" undersize it wobbled all over the place---Not what you want for centering.