how do I center the cutter?

[atfab]

How do I center the cutter on a shaft on a horizontal mill or find the edge of the work piece when using a cutter mounted on an arbor?
I can scratch it and call that zero or use a piece of paper and add the thickness.
with the vertical mill I use and edge finder
but how do you find the edge accuratly with a cutter mounted on an arbor?
There must be a trick that is accurate

 

[Tony Wells]

Most people probably do either blue it and touch off, or use a paper and compensate. You could measure off the "far" side of the cutter with a depth micrometer to the side of the shaft, then move over the cutter thickness plus half the shaft diameter. You could use a square on one side of the shaft and a parallel between it and the "near" side of the cutter. Or just calipers in place of the parallel. You could run the cutter past the end of the shaft in some cases and depth mic from the side of the shaft to the side of the cutter, doing the math to subtract half the cutter from half the shaft. Just remember that most cutters will run out just a bit, and cut a little over. You can be very fussy with the arbor and shims to minimize this effect. If your cutter is not running true, where you take your measurements will affect the centering accuracy. You should test the runout before cutting if size and centering is critical.

 

[atfab]

Thanks Tony the depth mic should work for most things I want to do. I was just wundering if there was some magic tool like a wigler or edge finder. LOL

 

[Kevin45]

If you are running your part in a vise, you can use Johnny Blocks to set up off the edge of your solid jaw to your cutter. You need to mic your workpiece for size, mic your cutter for thickness, subtract one from the other and set your Johnny Blocks to the size you need. Here is an example of what I am saying.