Re: ATM ROTOZIPPPING CIRCLES

[NGC704@aol.com]

Carl,

    I'd say the Roto Zip is being outclassed by the job and material. I 
suspect bit flexure to be your culprit, if not wandering in an overextended 
jig. Perhaps a little of both. That's a good sized circle you're cutting, and 
a pretty small tool to use for the job. Also, 1/2" Baltic Birch is not the 
easiest material in the world to cut, especially with a Roto Zip.
    I'm betting that a 1 1/2 hp router (preferably a plunge router), 1/4" 
straight cutting bit (preferably spiral upcut) and a suitable circle cutting 
jig will turn out perfect circles for you every time. Circle jigs for your 
router are extremely easy to make, as you may already know, and cost next to 
nothing.
    In the meantime, try making several passes to complete your cut, say 1/8" 
deeper at a time. I never try to hog 'em out in one heroic action, even with 
my big 3 hp router and 1/2" carbide spiral bits.

Regards,
Kurt Maurer
League City, Texas
http://members.aol.com/NGC704/NGs.html


In a message dated 4/6/01 9:13:57 PM Central Daylight Time, carl7@netzero.net 
writes:

> I'm using a Spiral Saw Rotozip with an 1/8" bit to cut a 30" diameter circle
>  in 1/2" thick Baltic Birch plywood - BUT, the cut wanders almost 1/8" from
>  perfectly circular within the first 30 degrees of arc on a test piece.
>  Everything seems to be tight on the circle guide I've created, so it seems
>  to be impossible.  Any ideas?