What could a 1-1/2hp shaper do that a 3+hp table mounted router could not
for a non-professional woodworker? Do you really need a 3/4" spindle? Are
the motors on shapers rated true hp and the router is funny hp?
IIRC most shapers can run backwards, not so on any router.
Since you can't put wood back on by running the tool backwards that
seem to me to be of limited utility but could help to reduce tearout.
Also STR that for the same HP, shapers have more torque.
Not only have I not used a shaper, but never saw anyone use the shaper
at the Vienna, VA woodworker's club I used to frequent. When they
mover to Springfield, they did not set the shaper up in the new shop.
A. Handle larger and reversible cutters.
B. Depends on the rating and the manufacturer. I'd not get a 3/4"
spindle shaper w/ less than 2 hp, however, particularly if it's a
Chinese motor variety...
The major advantage of the shaper over the router is simply the extra
mass that makes it more solid for heavy shaping jobs and the ability to
handle the really large cutters safely--panel raisers come to mind. The
disadvantage can be fewer profiles and higher cost. For the average rec
user, the router will probably do all he's like to want to do although
I'd hate to give up the shaper(s). (I've two, the LD 1/2" Delta and a
PM Model 27 w/ the 1/2 & 3/4 interchangeable spindles. But, I do a
bunch of things like windows and entry doors so the setup of the small
one to do the stub spindle coping cut while leaving the large one set up
for the main sticking cuts is a real advantage.)
One formula for horse power is ...Two pi nt /33000 where n rpm, and t = torque
In the case of the router which runs at about 20,000 rpm torque is
sacrificed for rpm or cutting force at the cutting edge [torque being force
times distance].As most router bits are small the effects low torque [force
times distance] are minimized . When the larger cutters are in use torque
does become a factor as the cutting edge is farther from the axis of
rotation . As a consequence the force at the cutting edge is reduced and so
shallower cuts are in order if the machine is going to operate efficiently.
The shaper on the other hand operates at considerably lower rpms and there
for for the same HP generates a much higher torque and thus cutting edge
below it's design operating speed will overheat the motor and be short lived
Several years ago some manufacturers to cover their tracts offered simpl;e
chucks for their shapers to facilitate the use of router bits .The shaper
operates at too low a speed to be used as a router consequently the
performance was lacking.......mjh
Depends on the bit diameter...large panel-raisers, for example, have as
large or larger cutting radii as do shaper cutters so the tip speed is
equivalent. But, for small diameters the lower rotational speed does
lead to poorer performance in general, correct.
You answer is wonderful, but as with the flowers that bloom in the spring
(tra la), it has nothing to do with the case.
Feed rate and depth of cut have more to do with the process than whether
it's an induction or universal motor, or equations of efficiency. In many
respects, the universal motor, with its constant-speed circuitry, will
produce a better cut as long as the feed rate is constant.
we are using .Regardless of the spring flowers, type of motor, or circuitry,
too deep of a cut or too high a feed rate will exceed the available "work"
output of the motor which in the worst cast will stall it .At the least it
will slow the motor down thus negating the cutter efficiency. Cutters are
designed to produce a quality finish by a combination of geometry for a
given speed and feed rate. Overloading , exceeding the given work output of
the motor on a regular basis will will end up reducing its life .
As far as constant feed rate goes I thought that is why we use power feeds
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