On Mon, 9 Aug 2010 01:13:24 +0000 (UTC),
(Larry W) wrote:

In article ,
Morgans wrote:

"Kevin" wrote

I didn't notice the flex until using my tenoning jig that rides the
fence. I don't bother clamping the stock in place as it takes too
much time when you have a lot of parts to cut, so you have to put some
significant force to keep it from riding up during the cut. But I
wasn't getting consistent cutting depths and that's when I tested out
pushing down on the insert and could see the sucker flex.

I put it to you like this; if you continue to improperly use a jig (as far
as I am concernened, not making use of a clamp constitutes improper use)
then almost any material is going to have some flex. Reinforce the insert
with a rib alongside the blade. Either that or get a metal insert made with
a sacrificial wood edge added by the blade.

I would urge you to reconsider using the clamp on a tenioning jig. Take the
time to be safe and accurate. One day, that will bite you.

It may not be clear that unlike a cast iron type jig that rides in the
slot that just has a face and a clamp, my jig has a stop at the back
edge so it's being held against two faces. My hand is way above the
cut. I consider it to be as safe as a cut with my cross cut sled.

--
Jim in NC



To the OP: Check your saw setup as previous posters have advised for
fence being parallel. And, consider modifying or making a new
tenoning jig with a base long enough so that the fore & aft ends are
always resting on the cast iron table, not on the insert.

It's not an alignment issue, the stock rises up before reaching the
back teeth. The jig doesn't flex the insert, the stock does. I work
with narrow stock, sometimes it might only be 3/4" wide. That makes
any downward pressure into essentially a point load. It also means
there isn't a lot of friction between the stock and the jig due to the
low surface area, and of course it doesn't weigh very much either, so
I have to supply the force. I use the same jig with a 45 degree block
added for miter splines, and I'd never had it rise up in that
circumstance, I don't know if that's just due to the extra weight and
friction or the different grain direction.

-Kevin