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

[Bay Area Dave]

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

[nospam_coloradotrout]

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..

[Tom]

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....

[George]

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.

[tmbg]

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 mortis> I tried to make loose 3/8" tenons with rounded corners and realized I'd

[stoutman]

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.

[stoutman]

sorry, thats Rogowski

[Swingman]

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.

[Lowell Holmes]

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.

[Bri]

[Bill Hodgson]

I haven't made any yet myself, but when David marks makes his loose tenons he uses a roundover bit that is 1/2 the the thickness of the mortice. So for your 3/8" mortice, you would use a 3/16" radius roundover to make the tenons. That particular bit isn't very pricey and you'll have it for a long time. Bill

[Bay Area Dave]

thanks, Bill. George also mentioned that. I was so "sure" that I'd need to use a 3/8" round over to make the profile for the loose tenon to fit a 3/8" mortise! I expected to align it carefully with the work piece, make a cut, and then turn it over and rout the other side. What I got for my effort was a torpedo shaped profile.

I looked in the router bit catalogs and figured that the bullnose bit (once again as George pointed out) would work, but geez, at almost $50 a copy I need a cheaper alternative. Little roundovers would be about a fifth that price.

dave

Bill Hodgs>

[George]

Ah, but you can get "bead" profiles that double as bullnose.

Note that if you are using loose tenons of good hardwood, you only need one size, ever. 3/8 of hardwood won't ever shear, and will glue in anywhere.

[Mitch Berkson]

Why would the tenon be moving at a different rate than the mortised pieces?

Mitch Berkson

[Bay Area Dave]

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 Berks> Bri wrote:

[Lawrence Wasserman]

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.

[Noons]

I don't think it's to allow for wood movement. It's to allow glue squeeze-out to have somewhere to go.

[Wes Stewart]

|Ah, but you can get "bead" profiles that double as bullnose. | |Note that if you are using loose tenons of good hardwood, you only need one |size, ever. 3/8 of hardwood won't ever shear, and will glue in anywhere.

'Cept you really have to hammer on them to get them into a 1/4" mortise [g].

[jev]

[Bay Area Dave]

thanks, George.

dave

George wrote: