suggestions for a drill bit to use
I'm currently drilling 1&5/8" holes into maple/walnut laminated blocks. depth of the hole is anywhere from 2.75 inches up to 3.5 inches and i'm drilling through the blocks all the way.
I'm using a 1&5/8" forstner bit and i'm noticing a CONSIDERABLE amount of tearout. each block has 5 holes drilled into it and the thickness between holes is about 3/16". naturally i'm getting alot of tearout because this is a very large bit, and it's very violent when it punches through the other side. I'm going at 450rpm on the bit, and when i get close to the end of the block, I go very slow on the pressure to minimize the tearout but I feel i'm wasting way more than what I want to.
The bits themselves are tool shop brand (off brand from menards) and though they're cheap, they've served their purpose well. they do not have smooth rim's on them, instead they're jagged and I think this might be the cause of my tearout.
I tried to purchase a bit from rockler which has only 2 teeth instead of a rim on the bit, and the teeth just keep snapping off during mid boring.
Would switching to a flat rimmed forstner bit alleviate tearout, or does the leading edge of the rim always cause this?
I'm really thinking that a different kind of bit is the way to go. I've found a 1&5/8" box cove router bit with 1/2" shank and i'm considering purchasing an extension that would allow me to mount it into my drill press and use that as my primary boring mechanism.
I was wondering if they make twist bits with 5/8" shanks that go up to 1&5/8" diameter, and if so, where would you find one. I've emailed grizzly customer support asking if they've got them, but i'm thinking that I'll need to go into the industrial supply to find something like this.
The last idea I had was to find a hole saw. THough not ideal, the smaller teeth might help fix the tearout. do they even make 4 inch deep hole saws?
any help is appreciated. Thanks.