So today I brought out my shop-built tenoning jig that rides the table
saw fence and made a mess of some tenons. Brought over the square and
saw just how much that sucker could rock on the fence. Hmm, it sure
didn't do that a few months ago.
My miter sled that I made in the winter worked really great, until the
summer when the oak runners wouldn't even fit in the miter slots due
to the change in humidity. After planing them down with a shoulder
plane it just never slid quite as well as it did before, and I'm in
real trouble when winter comes back. My plywood zero clearance insert
wasn't flush with the table anymore either.
Do I just suck at jig building or is every one else quietly cursing at
the jigs they made a few months ago?
Hate to burst your bubble . . . steel will do the same thing.
That's why heating the nut will help to free a 'rust-frozen' connection. And
inversely, if you want a tight fit for a pin, freeze it for a 'slip fit',
then drive it in.
Pack to the ply . . . this is one reason I use UHMW material for runners,
contact points, position locators, etc. Not glued, but screwed on or
otherwise attached. Typically somewhat adjustable for 'Zero'.
Regards & Good Luck,
I'm sure it's a common problem.... can't just be the two of us, Leuf..
I use a lot of non-wood parts now, including a lot of corian... a 3/4" strip of
corian is a great miter slot runner and can be sanded, drilled, etc... no
The plans for my next crosscut sled are for a transparent plastic base with
corian runners.... I took me a few years to admit to myself that jigs don't have
to be wood just because you use them FOR wood...
I do not think it is you rather the material you are using. I make most all
of my shop built jigs and shop-built tenoning jig and zero clearance inserts
out of 1/2" Baltic Birch. No problems at all with fit or warping. The
tenon jig is 7 or 8 years old and I live in a climate that has very high
humidity in the simmer and much lower humidity in the winter.
I had to scrap and re-build a router table fence when the first one
warped pretty significantly after about a year. I'm still confused
about this one - made entirely of particleboard and hardboard, which I
thought was supposed to be very stable. If I held a straightedge
against the fence, there was a space of almost 3/16" at the middle of
the fence. I'd suspect moisture, but the whole thing was
"finished"/sealed with titebond II all the way around. Oh, well. I
should probably get some UMHW plastic if I insist on being cheap and
building stuff on my own, and do it right (the third time...).
I do not know about particle board or hard board being stable however MDF
and plywood's and I suspect particle board and hard board are indeed stable
as long as the climate remains stable. Adding glue to a side of MDF can
cause it to warp. Multi layered plywood's like Baltic Birch tend to be
Might be the hardwood, Andy...
My router fence is 3/4" particle board, doubled up for 1 1/2" thickness and has
never warped or moved from humidity, AFAICT.. it's about 10 years old..
I'm still having trouble wrapping my brain around the zero-clearance
insert not being flush anymore. It's 1/2 inch BB, well actually two
1/4 pieces laminated together. It's got to be at least 1/64th proud
of the table now. I would have thought its expansion would be 5 thou
at the most.
I intend to remake the tenoning jig out of some 1/2" BB and I think
this time I will make a box slightly narrower than the fence and shim
it, attaching the short side with screws only. The first time I just
did a single piece across the top of the fence dadoed into each side
and then added bracing over it. I also want to make it easy to
replace the stop at the back edge, there's not much left of the one on
there now for the first inch or so above the table.
I'm thinking about getting some metal slides for the miter sled.
Something to do with my $15 off at woodcraft anyway.
> I intend to remake the tenoning jig out of some 1/2" BB and I think
> this time I will make a box slightly narrower than the fence and shim
> it, attaching the short side with screws only.
Might consider sealing the finished jig with a coat of 2# shellac.
SFWIW, 1/2" B/B is only 9 ply while 5/8" B/B is 11 ply and is the
standard for tooling for the die cutting industry.
Nice stuff for jigs if you don't want to use 3/4 B/B (13 ply).
No, but your learning about materials to use. I went to a plastic
supply house here and looked through their cut-off bin. For 5$, I
got 8ea 1x2x48 polyethelene slabs. I cut some to 3/4x3/8 for slot
runners, fine tuned with a surface planer. Also lucked in to 3/8
lexan - enuff to make 3 router table inserts for 20$. Try shopping
at a plastics place for cut-offs.
I don't have as much experience as some here, but he instructions for
the sled that I made were explicit about orienting the grain of the
runners so that the expansion occurs mostly in the vertical direction.
Using Northern Red Oak as an example, going from 5% humidity to 10%
humidity will cause a width change of 11 thou if flatsawn, but less than
half that amount if quartersawn.
I've seen second-hand dehumidifiers in the local Habitat for Humanity
surplus outlet for as little as $15. Some of these are missing their
condensate buckets, but you really need to set the unit up to drain
continuously to a floor drain, shop sink, whatever. In my humid NC mountain
climate, I run mine 24/365 and the humidistat keeps my shop at 50 percent
relative humidity all the time. Previous owner left a Sears unit with the
house and it's still going strong after five years.
No drain at all in the basement unfortunately, unless I tie it into
the plumbing. I suspect they don't have enough juice to get up 8 ft
without adding a pump into the bucket. I don't plan on staying here
long enough to justify all that.
It's not you, it's the materials you're using. I had made all of mine at
first out of whatever material was at hand, precisely because it was
cheap and available. The plywood in particular would assume all sorts of
compound curves after a year or so of sitting around in an unheated
garage. Subsequently I started making jigs out of scraps of hardwood and
various plastics. I came upon some free rectangular bits of 1/4 inch
thick acrylic sheet which work pretty well, and I've even cut up an old
white plastic cutting board (don't know what kind of plastic it is but
it doesn't swell or contract). Leftover bits of the better grades of
birch plywood, when shellac'd and then edge banded the way you'd do for
a book shelf to keep it from sagging, seem to last okay too. Never could
bring myself to part with the $$$ to cut up the Baltic kind for a jig
though, or to cut and trim plastic laminate over a raw plywood jig, but
maybe I should someday.
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