This is geared more to other cuemakers than customers but some
might find this interesting.
Recently, there have been some discussions about the best way to cut a
shaft. Some have been having problems getting a smooth finish on
the shafts. They are getting vibration and chatter when using a
router or laminate trimmer. This isn't an issue when cutting the
butt section because of it's larger diameter & solid heft. But a
shaft is thin & flexible and only gets thinner & more susceptible to
problems if your setup isn't perfect.
To get the best results, you need three things: a sharp cutter, minimal
cutter runout & perfect balance.
For years, the go-to cutter was a 5/8" router bit. They usually
ran fairly true and the diameter was small enough that any imbalance
caused by mis-matched brazed carbide wasn't a cause for concern.
The biggest source of vibration was caused by runout between the collet
& the bit. If you had a handle on that, you were OK.
Then there was a move to 3 flute (or more) slot cutters. The
idea was that you were increasing the number of cutting edges per
revolution, thereby reducing the chip load of each tooth, yielding a
smoother finish. The fly in the ointment was that you were, at the
same time, introducing even more opportunities for runout.
Now, not only did you have to worry about runout between the collet &
the arbor, you had to be sure the arbor itself was concentric - not
always the case with the budget arbors available.
Then, you had to make sure the slot cutter was running true with the
arbor. Often, there was .002/.003" clearance between the arbor &
the cutter. And that's enough to cause a problem.
Finally, even if you were lucky enough to get your arbor/cutter/collet
set up so it ran dead-nuts (sorry...technical term) when spun by hand,
you still had to be concerned with balance. Whenever you're
dealing with brazed carbide, there is the possibility that any insert
will be brazed to the cutter in a slightly different location.
Sure, the sharpening operation will true the cutting surfaces but if
there is a weight imbalance, even though the cutter might run true by
hand, at 25,000 rpm there might be enough bearing slop to allow some
runout to enter into the picture. And ANY runout is enough to git
that shaft a-vibratin'.
Here's
a
video showing a properly set up 3 wing slot cutter being
used.
I've been having good luck with a 4 flute carbide endmill. I have
twice the cutting edges per revolution. A Precise Collet insures
that it spins true. It's precision machined from a solid piece so
it is perfectly balanced - even at 25,000 rpm. And it's ground on
a helix so the positive rake helps it cut wood more cleanly. I can
take very light cuts with no fear of vibration or chatter.
The good news is that I can cut my shafts to within .001/.002"
of finish size. By eliminating the need to hand sand surface
irregularities away, I am able to maintain the shaft profile I've
designed. Plus, I don't have to sand shafts forever to make them
presentable to the customer.
See
this video
to get an idea of what I mean.
------------------------------------------------------------------------------------------------
...to be continued