I've am determined to replace the blade guard-splitter on my Jet Supersaw.
None of the aftermarket splitters does the job of a European Riving knife,
so I am designing my own. Jet did a beefy job in designing the mount system
for their guard/splitter. I wish they had finished it and put in a Riving
knife instead. Anyway, I have figured out how to build a knife that will
hug the blade and tilt with the blade. Height adjustment will be a manual
affair with two handscrews.
I am contemplating an automatic height adjustment design that would require
the blade be mounted in a sliding metal channel. This would be tied
mechanically to the motor mount which adjusts with blade height. The very
nature of placing the blade in a sliding channel would mean it would have
some slop in it, probably about 5-10 thousandths. My sense is that this
would be acceptable for a Riving knife application, provided it is a strong
By the way, an overhead, basket style blade guard will replace the existing
blade guard. I am considering a design pictured in The Workshop Book
published by Scott Landis.
All opinions are solicited and appreciated.
: I've am determined to replace the blade guard-splitter on my Jet Supersaw.
: None of the aftermarket splitters does the job of a European Riving knife,
: so I am designing my own. Jet did a beefy job in designing the mount
: for their guard/splitter. I wish they had finished it and put in a Riving
: knife instead. Anyway, I have figured out how to build a knife that will
: hug the blade and tilt with the blade. Height adjustment will be a manual
: affair with two handscrews.
: I am contemplating an automatic height adjustment design that would
: the blade be mounted in a sliding metal channel. This would be tied
: mechanically to the motor mount which adjusts with blade height. The very
: nature of placing the blade in a sliding channel would mean it would have
: some slop in it, probably about 5-10 thousandths. My sense is that this
: would be acceptable for a Riving knife application, provided it is a
: By the way, an overhead, basket style blade guard will replace the
: blade guard. I am considering a design pictured in The Workshop Book
: published by Scott Landis.
: All opinions are solicited and appreciated.
Go to Home Depot and spend some time studying the Ryobi BT3100.
Yeah, that's the $299 "toy" saw that includes all those advanced features
such as the riving knife you describe along with built-in dust collection
and a sliding miter table in the base purchase price.
On the basis of having owned (a) a contractor saw with the stock
guard/splitter (more accurately, without); (b) a contractor saw with a
Delta aftermarket splitter and Beis overarm guard; and (c) a small
sliding table saw what you are calling a riving knife arrangement, I
honestly think there's no point trying to remanufacture your saw. The
benefits are not there to justify that kind of effort, IMO, versus
going with the aftermarket splitter and guard set-up. Plus, it strikes
me you're going to exchange a small hassle, pulling and replacing the
aftermarket splitter every so often, with what sounds like a much
bigger one: manually adjusting the splitter height for each change in
...By riving knife, i assume you mean the arrangement where the
splitter is made to track up and down with the blade height, as well
as the tilt. I can see two__potential__differences versus the
aftermarket splitter. Depending on how it's been engineered, it
__may__hug the blade closer than the aftermarket version, and (b)
it__may__be possible to set it such that it stays a touch below the
top of the blade. I am skeptical that (a) makes a decisive difference,
even where true. (b) is a useful attribute, since it means it can stay
on for non-thru cuts. But (unlike riving knives), the aftermarket
splitters are designed to come in and out easily, somewhat offsetting
this...Anyway, as long as the splitter, a splitter, is in place when
it's supposed to be, I would suggest other issues, like having a safe
way to crosscut, and a good guard, warrant more concern safety-wise.
Thanks for your comments Woodstock. I'm not opposed to spending the money
on aftermarket if I find something that does what I want. Easy removal of
the splitter is not a meaningful option for me because it means the splitter
is not designed to work with some cuts. A Riving knife can stay attached all
the time. Also I have no use for the kickback pawls used in American
Designs. I found these actually caused more hangups and potential for
problems than they saved.
I looked and looked and looked for an aftermarket that I liked. The Beis
guard is nice and I really considered buying it, but it was not available
for my saw when I checked (jet Supersaw).
Your comment about exchanging hassle of changing heights vs. removal of the
splitter is not correct. Any splitter that does not have the height
adjustment hassle is one that is designed for a fixed (maximum) distance
from the blade. I can accomplish the same thing with my design - just set
it for maximum blade height and forget it. It will do the same job as the
aftermarket splitter. By the way, my current splitter design took 2 hours of
cutting and trying and $3 worth of parts to make it work. It was worth it to
me. It seems that its the same hassle as one of the delta splitters that
also uses a thumbwheel to mount/dismount the splitter. If I get this
automatic height adjustment thing working, it will be superior to anything
on the aftermarket by a long shot.
Now back to the guard - you are absolutely dead on. You really have to work
to save any money over the aftermarket items, assuming your time is worth
something. I guess I get absorbed by the challenge. I also think I can make
better dust collection than some of the aftermarket items I've seen.
Also I have no use for the kickback pawls used in American
Basically agree on the pawls, though I found them generally
unobjectionable on the aftermarket splitter I had (which was the Delta
one). At one point I contemplated adding a sliding table accessory to
my old saw and/or making a crosscut sled that could be used with the
aftermarket splitter in place. It seemed that both should be workable,
provided the pawls were removed. I did not test this approach out in
the real world before getting a different saw...but assuming it would
work, it'd cover all situations except non-thru cuts, which would be
pretty high percentage of all cuts.
I'm thinking maybe you're referring to the Beis splitter, and not the
guard. I have seen the claim that the Supersaw's internal mechanism is
the same as the Jet contractor's saw. The Beis web page shows a
splitter for the latter model. Maybe that would work, if the
mechanisms are indeed the same? If you do mean the guard, I have the
Beis one and believe it should present no problem with the SuperSaw.
It has a pretty big range of adjustment for saws with different front
to back and right side table formats.
One of Tage Frid's books features a shopmade splitter/guard, fitted to
a Rockwell saw. It was fixed to the standard attachment point under
the blade insert, but was curved in shape to complement the blade,
rather than upright like the aftermarket kind, and had a wooden crown
guard on top...interesting design that somewhat mitigates
this...admittedly, poses some guard issues, however.
I can accomplish the same thing with my design - just set
If I get this
Sounds like it would be.
...You've probably thought of this already, but engineering in some
easy means of micro-fine adjustment would be a big plus. On my saw,
the splitter is mounted to a heavy piece of folded steel that ties
back to, and travels up and down with, the arbor. There's no provision
for adjusting the alignment and out of the box it was not acceptable.
Scotch tape shims and trial and error eventually did the trick but it
would have been nice if some adjustment were built in at the
factory...The alignment of the splitter is critical, obviously, and
small misaligments in the bar that carries the splitter are much
exaggerated by the time they reach the business end of the splitter
because of the distances involved and the inevitable vibration.
I feel the Beis guard is a very high quality piece of equipment that
one would be hard pressed to better as a guard. I've don't have my
guard hooked up to dust collection; based on what I've seen, I'm sure
you're right about being able to surpass that aspect of it.
Anyway, I hope you'll post a description/pix of your design once
you've built it. It sounds like a pretty interesting project.
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