Do you round off tenons to fit routered mortises or chop the corners off?

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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!
dave
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i am no expert.. only what i've seen
round over the tenons w/ chisel and sandpaper to fit the rounded mortise.
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..
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Well, I just cut the profile with a "cordless" saw, and chisel the tenons down to the shoulders. Tom >Subject: Do you round off tenons to fit routered mortises or chop the corners

Someday, it'll all be over....
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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.

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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:

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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.

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sorry, thats Rogowski

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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 mortises.
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.
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Hey Dave,
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.

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I thought this FWW video tip looked interesting. As usual they make it look easy. Haven't tried it myself yet but I will. http://www.taunton.com/finewoodworking/pages/wvt051.asp

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Bri wrote:

In the video, he makes the tenon 1/16" short to allow for wood movement. Why would the tenon be moving at a different rate than the mortised pieces?
Mitch Berkson
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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.
dave
Mitch Berkson wrote:

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Mitch Berkson <mitch-at-bermita.com> 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.
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Larry Wasserman Baltimore, Maryland
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I don't think it's to allow for wood movement. It's to allow glue squeeze-out to have somewhere to go.
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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"

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jev wrote:

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.
Mitch Berkson
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Er... 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.
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Nuno Souto
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snipped-for-privacy@yahoo.com.au.nospam says...

Er.... Huh???
I guess they really do think differently in Oz :-).
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Where ARE those Iraqi WMDs?

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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.
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Nuno Souto
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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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Larry Wasserman Baltimore, Maryland
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