I purchased a slitting saw and an arbor to make - well, slits. The first
slit ever I made was using a Dremel abrasive disc in my mill. It worked
really well but I am told that it is not a recommended thing.

So here they a

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B044

http://busybeetools.ca/cgi-bin/picture10?NTITEM=T747025

I tried to make a slit in an aluminium block to make a boring bar holder.
The first thing I noticed that the saw did not run concentrically (instead
of 'vrrrr" it went 'vroom, vroom'). I finished the cut (using a lubricant
and a slow speed). The slit looked awful, but this was partly my fault as I
forgot to lock the Z-axis in all the excitement. Anyway, it is functional,
so no real harm done.

I had a close look at the arbor and at the saw. The saw does not have a key
slit (proper name?) contrary to the picture, just a circular central hole.
The diameter of the central hole is 0.872" allowing for my calipers reading
0.001" under. It appears perfectly circular. The tooth length measured from
the inner aspect of the central hole varies by 0.008".

The run out of the arbor shank in a mill 1/2" collet was less than 0.001".
The run out of the 7/8" ring, however, was 0.015".

I put the saw on the arbor and noted a slight laxity of the fit on the 7/8"
ring. I tightened the whole thing as I would normally and then measured the
"run-out" of the teeth by checking them carefully individually. The run-out
was 0.030".

The questions a

1) Is this situation common?
2) Is it acceptable (I cannot see it myself - right now I am cutting with
only a few teeth - maybe when they wear out the other teeth will start
cutting ;-)
3) Would purchasing the same system from an "industrial" vendor be more
likely to perform satisfactorily?
4) Is this sort of arbor a good thing anyway? Would another type perform
better?
5) Is there anything in the setup of the saw I could have done to make it
run concentrically?

Thanks,

--
Michael Koblic
Campbell River, BC