Questions about rotary engraving bits, materials, feed speeds

[Jim Underwood]

I'm trying to price a job where there needs to be fine detail on top of a "puck" shape. The project is a master mold in which polyeurethane will be poured to make a mold for these concrete "pucks". They'll be about 2-1/2" diameter. Think of a hocky puck with a "N" engraved into it, and you'll have the picture of the finished part. For most of the master, I can use MDF, but for this fine detail in the "N" I need something that will hold detail down to at least .030" diameter.

But before I can price it, I need to figure out if I can do it, and whether it will be a reasonable price.
I'm finding even my 1/16" tapered ballnose bit to be too blunt an instrument to create such fine detail.

I do have a 10° tapered flat engraving bit with a .020" diameter, (Bits and Bits 815-PR10) but I've never used it for anything. I initially thought I'd use it for creating better detail for turned box inlays, but just haven't had the guts to try it on wood yet.

Would this small bit work on wood, MDF or Corian? I'm afraid the MDF won't hold the detail I need, and I'm afraid the bit won't stand the pressure from the Corian, or even cut well. I think it's meant to be used in wax... Would a tapered ballnose bit work better?

If you can suggest a proper bit and material I'd be most appreciative.

[Ken Dolph]

You are right that this bit is for wax. The tapered ball end bit will be perfect and Corian will hold the detail better than MDF.

[Keith Outten]

Jim,

Call Centurion Tools in Louisa County Virginia and ask for Fred. They manufacture router bits specifically for CNC machines and they have a bit that will work for your project. I won a set of their bits at a ShopBot Jamboree a couple years ago and the bit you want is in my set. I can take a picture of the bit but it might be a couple days before I can post it here as I have a deadline of tomorrow morning to install a job here in the county.
.

[Jim Underwood]

Fred said he doesn't make any bits as small as I need...

[Paul Phillips]

Jim, have a look at these guys, maybe they have what your'e looking for.
http://www.cetdirect.com/
or
http://www.micro100.com/

Hope this helps.
Paul

[Jim Underwood]

Thanks Paul. I'll take a look at those places. It's always good to know about several suppliers.

I did talk to the guy at Bits and Bits yesterday, and he recommended a couple of bits for me. If my client oks the proposal, then I'll order....

[frank cloutier]

Paul,

Precisebit.com is the source I have used for extremely fine bits. See the following link:

http://www.precisebits.com/products/...allnose125.asp

There you will find bits down to 6 thousandths (.006) I have also found the owner to be extremely helpful.
The phone number is: 1 719 488-9640

Hope this proves helpful...

Frank