All,
I just finished cutting 2 thru-mortices, 4.5″ long, in 1.5″ qtr. sawn white oak…I have about 6 more to cut. I’ve cut mortices before but not where the mortice will be seen in the finished product….and I wondering if there are any tricks to keeping the visible shoulders nice and clean and sharp. I’ve made it as sharp as I can with a wide chisel…carefully paring, etc. ..but maybe there is a saw dust trick or something like that that I don’t know about? thanks
Replies
BG,
The edges of the mortise will look better and will be less prone to tear out if you bevel them after the mortise is cut. A small sharp metal file is an effective tool to bevel the edges.
John W.
JohnW,
Are we talking a very small bevel...maybe 1/16" at a 10 degree angle out from the mortice?..or is something larger/smaller more attractive?
A small bevel, about a 1/16th across it's face, but at a 45 degree angle.
John W.
What I do is leave the stock a little thicker than needed, then after the mortice is cut take the last bit off with the plane it cleans up the edges pretty nice.
Scott
Scott,
"What I do is leave the stock a little thicker than needed, then after the mortice is cut take the last bit off with the plane it cleans up the edges pretty nice."
Are you saying you don't cut the mortice on the exposed end to the scribed line...but hit it with a plane as your fitting the tenon? My mortice is 3/8" ...what knid of plane?....I was thinking about using the plane blade only which would give me a nice 2" flat back for paring....then a bevel as John W suggested.
What I do is for 1 1/2 stock is leave it at 1 5/8 until after I have cut the mortice, then plane down to 1 1/2. This will clean up any small break out and leave nice clean shoulders.
Scott
Scott,
Ahhh...fascinating ! Sounds kinda like an Ian Kirby method. Of course, It's too late for me to apply that solution ...but I'll remember it for next time. thanks
The tear out happens on the exit side. You can avoid most of it if you cut the mortises a little over half way through and then turn the piece over and cut the rest of the mortise from the other side. Obviously important that your fence is stable so the two cuts meet.
Jim
Jim,
I'm doing these by hand..but I have been flipping the leg over and cutting in the opposite side with chisels...at least a quater inch or so. I'll bet those morticing machines make this a piece of cake...(sigh)
Even with a mortising machine you need to flip the piece and cut from both sides.
If you're doing them by hand, mortise in about 3/4(or more) of the way from the inside, then flip it and cut the remaining from the face side. Pre-score the mortise with a knife beforehand. Don't pry on the edges on the show side when removing chips.
BG, f you must make multiple through mortises, you might make yourself a jig or fixture so you can use your hand held router to attack it from both sides (Meeting in the center)
You wind up with four radioused corners though, but easy to chisel out.
Ive done this not only for radioused mortises ,but also for radioused tenons to fit.
Stein.
Edited 8/27/2003 5:27:43 PM ET by steinmetz
Stein,
Actually, that is the way I have always cut my mortices..with the router using a simple jig on the workbench. This time I decided to do them by hand for the experience and...and...the router has been modified to fit into the router table. I thought about cutting them on the new router table but decided to try them by hand..and if I screw them up..finish on the router table and make appropriate adjustments in the tennons, etc.
Currently, I have only screwed up once which will result in three sets of thru-tennons while the plans called for two....;-)
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