Robert Bonomi wrote:

In article ,
Lon Ponschock wrote:



I am not much familiar with all the things that can be done with and
cautions
about using the spiral saw.


Is there a discussion which specializes in using this tool for home
woodworking?


I'm interested in the sorts of routing that can be done with the
tool and preferred
bits and jig adapters for rabbetting and circle cutting.


My main application is doing the final trim work on audio speaker
cabinets:
driver cutouts, terminal cutouts and finish work for flush mounting
drivers and edge trimming (roundover) of 3/4 birch plywood on small
surfaces with other
larger projects to come. No veneering at this time, but that is another
likely application



Any help or how to articles also appreciated.


My unit is made by Tool Shop. It is 30,000 rpm with an accessory kit.

AH ha! Got it at Menards, I betcha. Their house-brand special.

The bad news -- That tool, and *any* similar one, regardless of
manufacturer, are the WRONG THING for the type of job you propose to
undertake.

Spiral saws are designed to work in _brittle_ materials -- ones that
'powder'
when 'hit' with a sharp edge. They're _great_ for drywall, and, as long
as you're careful about heat build-up, you can do amazing things on
ceramic tile, too.

For cutting wood, on the other hand, they are 'medium dreadful', to put it
charitably.

The bits don't have big enough 'flutes' to clear the wood chips, so they
are *very* slow cutting, Like only a few (maybe 5) _inches_ per minute,
in 3/4" stock, *IF* you can keep from breaking the bits.

Due to the small diameter, they don't have the structural strength for the
side pressures, and you'll break bits *real* often. Like, if you're
lucky, you'll get 4-6 _inches_ of cut in 3/4" material, per broken 1/8"
bit. Don't even _think_ about using the standard 1/16" ones.


For any sort of a powered cutting edge, you want more-or-less the same
lineal speed at the cutting edge, regardless of the size of the cutter
being used. What the 'correct' lineal speed is, does depend on the
material, but the speed can be regarded as a constant for any specific
material.

_Standard_ setting on a router will spin a 3/4" diameter bit at around
22,000 RPM. This is equivalent to about 17,000 RPM for a 1" dia. bit.

To get an equivalent 'cutting edge speed' from a 1/8" diameter bit, you
have
to spin it 8 times faster than that 1" bit -- or around 135,000 RPM.
More than _four_times_ what your tool is capable of.


A reasonable light-duty router can be had for under $100. See the Skil
1815, for one example. It has an 'edge guide' option -- which includes
circle-cutter capability -- that sells for about $15.

For less than double the money (i.e. under $200) you can get a "good"
router. And under $300 will get a top notch 'commercial grade' unit.

Don't know about the model he has, but a Rotozip takes standard router bits
in addition to the special purpose cutting bits.

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)