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I'm working on a breadboard end with pinned tenons for the lid for the hope chest I'm building. The material is 3/4 walnut, about 17".
Would it be better to use 8x50 dominos for the tenons, pinned with 1/4" dowels, or make my own tenon material about 1.5" wide by 6mm thick, as deep as the DF500 will cut, and pin with 3/8" dowels?
The 8x50 dominos are certainly easier, but I'm worried about the elongated holes for the dowels compromising the tenons themselves.
I have some scrap oak pieces, so I'll probably try both with that, but looking for opinions.
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I'd prefer the tenons to be just a little wider than Festool tenons. Make your own, and use the Domino to cut adjoining mortises....at least that's the way I would do it.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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I agree with Fred. I also think you need longer tenons. You need a stub tenon running the full width of the breadboard end and probably 3 long tenons. the center one glued and/or pinned and the outer ones pinned in elongated slots in the tenon. Both 1/4" or 3/8" pins will do the job so use whatever you like. But the long tenons need to project into the breadboard end at least 1-1/2" IMO and a 50 mm Domino will only give you 1" unless you cheat on the mating mortise and that's not a good idea. I would use an 8 mm or 3/8" bit if Domino makes one of the those and cut the mortises as deep as possible in both sides. I'd make the mortises at least 1-1/2" wide. Fit the center tenon snug in the mortise but make the outboard ones at least 1/4" narrower and center them in the mortise.
John
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"I'd prefer the tenons to be just a little wider than Festool tenons. Make your own, and use the Domino to cut adjoining mortises....at least that's the way I would do it."
That's my thought as well. I finally got my drum sander so making my own thin tenon material isn't as daunting (my Dewalt planer has a history of applying rapid entropy to shorter pieces thinner than 1/4)
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"But the long tenons need to project into the breadboard end at least 1-1/2" IMO and a 50 mm Domino will only give you 1" unless you cheat on the mating mortise and that's not a good idea. I would use an 8 mm or 3/8" bit if Domino makes one of the those and cut the mortises as deep as possible in both sides. I'd make the mortises at least 1-1/2" wide. Fit the center tenon snug in the mortise but make the outboard ones at least 1/4" narrower and center them in the mortise"
If I make my own, the DF500 can cut 28mm deep, so just a bit extra. I could made them deeper with a drill after cutting the initial mortises. If it was for a table, I would do that for sure. I know the DF750 is the better machine for these things, but I have to keep costs somewhat reasonable for what is primarily a hobby.
I would probably make all of the tenon material the same width for ease of fabrication, but I would cut the outer mortises on the breadboard side wider to allow for the movement.
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Some of this sounds like overengineering to me. You can get 50mm tenons with the DF500, which will get you a symmetric one inch projection into the breadboard end. What I have done in the past is three fixed (glued) tenons in the center (aligned closely, zero play) and then tenons in elongated slots every 8" or so to the end. Spacing can vary for your application.
If that's insufficient in terms of projection or strength, I have never noticed it. I have two pieces that have done this - a sapele wine cabinet (which is supported underneath, so no stress on the breadboard end) and my brother's walnut dining table, which is unsupported and subject to his two young boys. Both have held up wonderfully.
Mind you, there will not be any problems if you overengineer. I just don't see it as necessary.
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Did youbpin your tenons? I'm more concerned about what the elongated holes will do to weaken the tenons than the depth in this application.
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(11-30-2021, 12:41 PM)lincmercguy Wrote: Did youbpin your tenons? I'm more concerned about what the elongated holes will do to weaken the tenons than the depth in this application.
I did not. It really isn't possible to pin them without compromising strength. If you cut your own and used the max width on the DF500, I'm sure you could. But the factory tenons didn't leave any room for that.
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You aren't going to sit on the hope chest, are you? Go with FS7 , use factory dominoes, and make it a simple job.
Simon
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(11-30-2021, 01:47 PM)FS7 Wrote: I did not. It really isn't possible to pin them without compromising strength. If you cut your own and used the max width on the DF500, I'm sure you could. But the factory tenons didn't leave any room for that.
And that should be reason enough to use longer tenons. Breadboard ends use pinned tenons for a reason - to prevent the ends from pulling away from the mating member with seasonal changes in humidity. You can compensate by cutting the breadboard with a concave inner edge but why not just build it right to start with? 6 x 50 mm Dominos for a breadboard on the end of a dining table is far too light for my liking. For the OP's project, yeah, OK, maybe. But what's so hard about just routing a deeper mortise? 3/8" x 1.5 - 2" is not hard to do with a plunge router and double edge guide or template and bushing.
John
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