Okay, got the mortises chopped, tenons cut, and the fit is fine... How the
hell to I square up the shoulders evenly so that the tenoned piece fits
cleanly? I feel like I am starting off with a high chair and uneven legs
and have the feeling that I'll end up with a stool by the time I get the
I had thought about using the tenons as a "stop" but they are of unequal
lengths. I could trim them all to the same length, but hate to give up the
This is all for some screen doors, so it's important that the rails are all
the same length for obvious reasons. It's hard enough to keep things square
when I *do* know what I'm doing.
I seem to recall a quote from Mark Twain saying that the cause of trouble
isn't from people that people that *think* that they know what they're
doing, it's from what people that *KNOW* for sure, what just *isn't* so...
Any help, TIA... I'm sure someone here will explain a method shortly that
will embarrass me in its' simplicity...
Cut your stock exactly to length, that includes your tenon (tenon doesn't
have to be exactly seated to bottom off mortise) length. Use a stop block,
with a piece of tape, here's the million dollar tip: cut the all the faces
of your tenons with the stop block and tape, then remove the tape from the
stop block, before cutting the end cheeks. This minute extra bit of height
provides an all around, super tight gapless joint.
A quick paring with a chisel, to ease an inward angle towards your tenon
along your cheeks.
Don't forget to score you tenon, if it's a tight fit. Scoring it will
prevent any hydraulic pressure, and let excess glue escape (same reason
store bought dowels are scored).
Cheers, and good luck
There is at least one way to recover from the situation using a table saw
and a crosscut sled, or a miter gauge with a fence attached, but, depending
upon how far off you are now from being square and the desired length, you
may have to settle for a bit off the final length of your rails to get them
all the same size and still square to the stiles:
FIRST: mark one side of each rail (on the tenon) with an "X" so that you
always know which side you're going to put up against the stop block in the
Now, carefully using a stop block on your fence, ADJUSTED INDIVIDUALLY FOR
EACH RAIL, and with the blade height adjusted for the height of the
shoulder, square up shoulders on the rails, ONLY on the side marked "X", and
taking as small a cut as possible to get the shoulders square all the way
around the rail.
The goal of the first step is to get one end ONLY of your rails with the
tenon shoulders perfectly square all the way around.
SECOND: Set a stop block on the fence of the sled/miter gauge, that rides
above the cheek of the tenon, and catches the lip of the tenon shoulder that
you squared up above (the one marked "X").
Place, and securely fasten, the stop block so that the distance between it
and the same side of the saw blade is the same as the desired length of the
rail from shoulder to shoulder (without regard to the current tenon length).
Once set, do NOT move this stop block!
With the blade height still set to the shoulder height, and now with the
shoulder marked "X" against said stop block, make your squaring shoulder cut
on the opposite end of the rail.
Depending upon how much you had to fudge, you may have some cleanup on the
tenon cheek to do, but your shoulders on opposite ends will now be parallel
to each other, and the rail will be the desired length from tenon shoulder
to tenon shoulder.
There are other ways to do this, but the above will keep you from having to
cut your tenons to the same length after the fact, which is always a kludge
at best and rarely results in all rails being the same length.
In the future, always batch cut the shoulders of the tenons on the rails
using a fence and stop block while the tenons are ALL the same length ...
you can always go back and trim/bevel individual tenons shorter if need be,
but you will still have that sacred, and square, distance between the stiles
set into your rails as gospel that you can take to the bank ... along with
your mixed metaphors.
Hope this was clear enough.
Have I got a deal for you John!
Your post regarding your trials and tribulations with the
mortise and tenon joints on your screen door project got
me off my butt and make the Loose Tenon Jig that was in
the April 2004 issue of popular woodworking. And of
course I had to come up with some additions for it -
for doing mortises in mitered corners (I'm doing a
jewelry box with wrap around grain and didn't want
to biscuit it together. (no, the jig is not made of
rosewood with ebony stops and there are no wooden
After figuring out how to make it and then playing with
it enough to understand how to use it I put up three
web pages that might a) get you to make this jig and
b) solve your mortise and tenon problem. You do
have a router and an edge guide for it I trust?
Here's the url (no pop ups, no adds - just some
hopefully useful information. All one line so
watch the line wrap.
Forgot to mention chamfering the ends of the tenon
and if you're anal retentive, the mortise as well.
Makes getting parts together a little easier and gives
a little space for glue squeeze out inside the joint
where it won't show.
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