I tried to make loose 3/8" tenons with rounded corners and realized I'd
have to buy a pricey bit for each radius to make them easily on the
router table. I thought I could just use my 3/8" roundover bit. Didn't
realize that it has a straight portion on the profile...
Do you guys chop out the mortises rounded ends or what's your pleasure?
do those little gadgets for chiseling corners work? I saw 4 different
kinds at a WW show and couldn't see how you locate it over the work
precisely. And how deep do they go? Is it far better to have a chisel
narrow enough to chop down the end of the mortise? If I'm only going to
CLEAN a mortise, but not create it with a chisel, do I buy a different
chisel type than a mortising chisel?
I want to do mortising the easiest way (read fast) and accurate, without
buying expensive dedicated tools. Am I going in the right direction to
consider using upcut spiral bits in the router table, clean out the ends
and either make a tenon or make 2 mortises and make loose tenons?
There's lots of choices but I just feel there has to be a "best" way.
Thanks, as always!
i am no expert.. only what i've seen
round over the tenons w/ chisel and sandpaper to fit the rounded
the holding strength of this joint is on the wide side of the tenons
try to get the greatest surface areas to be as smooth as possible..
and to fit snugly..
Ah yes, radius versus diameter bite you?
Proponents of loose tenons normally advocate the full bullnose bit, rather
than 1/4 round. Then you just bullnose both sides of a bunch of tenon stock
at leisure and chopsaw what is required, as required. Use a fence to
support the outfeed.
I've got a benchtop mortiser, but when I didn't, I chiseled square mortises.
adjust the depth of your router so the roundover bit makes a smooth
continuous radius without leaving the ridge...
it can be done, I promise!
a mortising chisel is ideal for creating mortises, but not for cleaning
out corners of a routed one. Buy a set of halfway decent bench chisels in
various sizes, learn to use them, learn to sharpen them. They actually do
more things than open paint cans!
On Fri, 16 Jan 2004 06:44:22 +0000, Bay Area Dave wrote:
I read in Joinery by Rogogowski (excellent book!!) that you should round
over your loose tenons with a bit 1/2 the thichness of the tenon stock. For
example a 1/2" tenon should be rounded with a 1/4" round over bit.
I have never made loose tenons,but I am considering doing them exclusively
because my tenons rarely come out right. I have trouble getting the
shoulders to line up perfectly all the way around the tenon.
About 30 seconds with a pattern makers rasp, and a little practice, will
round the corners of the tenon's cheeks sufficiently to fit your router cut
Do it carefully, but don't agonize over it ...it ain't rocket surgery. The
fit, and glue, on the long grain cheek of the tenon where it contacts the
mortise sides is where you get the majority of your joint strength.
Get yourself a gouge with close to the proper radius and round the tenons
with the concave side towards the corner you are rounding. It works great.
I've never seen anyone else suggest this, but I'm sure I'm not the first.
Kelley Mehler uses a segment of a sanding belt like a shoeshine rag to round
the edges. That works great too.
I haven't seen the video, but if the mortise is 2 inches long I agree
with the absurdity of it; there's not gonna be a 1/6" of an inch of
movement in a 2" long mortise. If that was the case, think how much
movement you'd have in a 48 wide table: 1.5 inches!
Perhaps there's another reason like making sure the shoulders are snug??
I don't know; just asking.
Mitch Berkson wrote:
I've always seen the reason for cutting the tenon slightly short is so
that glue has somewhere to go, and by the way, imagine the consequences
if the tenon was just a little too long instead of a little too short. But,
the tennoned piece IS at right angle to the morticed piece, so in the
normal M&T, the mortised piece will "move" parrallel to the tenon
direction, while the tenon itself, will not.
The tenon and mortise move at different rates cuz you have a cross
grain joint - the grainruns at right angles to each other for the
tenon and the mortise. So he leaves the width a 1/16 short on the
tenon for wood movement and the length of the tenon a bit short for
glue space. Of course, having the tenon width short also gives glue
somewhere to go.
On Fri, 16 Jan 2004 11:40:23 -0500, "Mitch Berkson"
OK. Good point about the right angle grains. But unless you're using
silicone caulk to hold things together, isn't the glue going to try to
prevent any movement? Maybe this is an argument for pinning that side of
the joint and not using glue.
Right angle grain is not cross grain. That is a common mistake.
What is cross grain is when you have end grain against
long grain. As in the *end* of the tenon against the bottom of
the mortice. Long grain against long grain, which is what
a M-T join mostly is, is never a problem. Or else M-T would not
be a strong join. And it is one of the strongest.
No. It's the same everywhere. Short grain is the end-grain.
Long grain is along the grain.
You must NOT glue short grain to long grain.
Nor short grain to short grain. It won't work.
But you can glue long grain flat to long grain, at any
angle you may care. That's how M-T works, how lapped
joints work, how virtually every wood glue-based join works.
Think about it, you'll see what I mean.
You can glue it and it will be storng for a while, but if the joint is
more than a few inches wide and the grain in the 2 pieces is at 90d,
it'll split one of the pieces sooner or later. Otherwise, breadboard
ends, for example, could be just glued on a T&G instead of pinned &
allowed to 'float'
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