Dremel circle cutter

Ted Novak TRA#5512

I use a similar tool, a RotoZip. Works fine. Tom

The problem I run into with these is that the skinny (~1/8") bits tend to deflect. When cutting the outer circle, you can cut it slightly over sized, then adjust, and cut it again. During the second pass, because you're removing so little material, the bit tends to stay on path and you get an accurate cut.

So far, so good.

When you cut the inner circle, you get the same thing - the bit deflects. But, there's no second pass available - the first pass removes the pilot hole that guides everything. So you're SOL on that one for making a second cut - you gotta get it on the first pass.

Basically, in my experience, these give unsatisfactory and inconsistent results for centering rings, but you can get decent bulkheads if you're patient.

Doug

The problem I run into with these is that the skinny (~1/8") bits tend to deflect. When cutting the outer circle, you can cut it slightly over sized, then adjust, and cut it again. During the second pass, because you're removing so little material, the bit tends to stay on path and you get an accurate cut.

So far, so good.

When you cut the inner circle, you get the same thing - the bit deflects. But, there's no second pass available - the first pass removes the pilot hole that guides everything. So you're SOL on that one for making a second cut - you gotta get it on the first pass.

Basically, in my experience, these give unsatisfactory and inconsistent results for centering rings, but you can get decent bulkheads if you're patient.

Doug

What thickness material are you cutting that your bit gets deflected? My rings are usually 1/8 plywood and I have no problem at all. I cut the disk with the Rotozip and cut out the center hole with a hole saw.

Tom

That's a good question, Tom. I must admit I've been cutting stuff quite a bit thicker than 1/8" - I have definitely experienced it cutting speaker cabinets pieces 1/2" to 3/4" thick. But I want to say I've experienced it on thinner stuff, too.

Doug

That's a good question, Tom. I must admit I've been cutting stuff quite a bit thicker than 1/8" - I have definitely experienced it cutting speaker cabinets pieces 1/2" to 3/4" thick. But I want to say I've experienced it on thinner stuff, too.

Doug

Yes, with those thicknesses I am not surprised. That's a little much for that tool. With 1/8 inch plywood you can adjust the bit to protrude just a hair below the wood. There is no way that bit will deflect. Unless the OP is cutting rings for very large rockets I think he will get good results with the tool. Regards, Tom .

I've got a "shaper/router table" kinda like what they show on the Dremel accessories page, as well as a Dremel router base (not shown). I had problems with deflection too when trying to cut a straight line with the table, or when cutting a circle with the router base. I read the instructions and found I had left a piece off. It is an adapter ring that goes at the tip of the motor to keep it centered in the holder. Without it, the tool can flex slightly in the clamp. Don't know if the circle cutter under discussion has this part, but it sure made a difference with the bases I use!