When cutting tenons do you make them a bit shorter than the depth of the mortise to allow for some glue squeeze out into the bottom of the mortise? How much? 1/16? 1/8?
[OP]
Contributor
When cutting tenons do you make them a bit shorter than the depth of the mortise to allow for some glue squeeze out into the bottom of the mortise? How much? 1/16? 1/8?
Scott Vroom
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.
Contributor
Of course, otherwise you can get hydraulic lock.Originally Posted by scott vroom
I leave 1/16 to an 1/8 Scott...........Regards, Rod.
That's what I do.
Lee Schierer
USNA '71
Go Navy!
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Member
I leave an eighth as well as making sure my tenons are grooved to allow excess glue to squeeze out.
good luck,
JeffD
Yes. I also score the cheeks to avoid hydraulic lock during assembly.
"A hen is only an egg's way of making another egg".
– Samuel Butler
Member
I don't have near the experience these others have, but in the mortises I have done I've left 1/8" of extra depth.
Contributor
Likewise, though as much for insurance that I can make the joint tight as for glue space. For better or worse, I seldom get that perfect piston fit on all sides and corners that would make it completely impossible for glue to escape. The mortising chisel leaves some scratches and scrapes on the sides of the mortise and I don't generally go back and make them perfect.
Member
Yes and I also leave a little room at the ends of the mortise so the glue has a path to escape. The space at the bottom is for several things. Sometimes small pieces of wood are shaved off when you insert the tenon for final assembly. They need somewhere to go. I don't always tighten the clamps all the way on test fits so a little extra space also helps to ensure the tenon doesn't bottom out. Just seems like the cheeks are what holds the joint so they need to be tight and the other areas less so.
Member
on flat bottom mortises with no shoulders on the tenon no i don't leave a space. the bottom become the shoulders for that type joint. On the chain mortiser and the chisel mortiser i do. I leave the smallest amount of space on the swing chisel Maka. all three have different bottoms to deal with. Its best to leave very little in gap for spiral fluted dowels as the bottom injects glue back up from the bottom into the flutes . this helps swell that end and they hold better.
Last edited by jack forsberg; 03-06-2015 at 10:24 AM.
jack
English machines
Member
I leave about 1/16" unless they are in a leg where they touch at a miter in the points, then I keep them back maybe 1/32"? I like to undercut the inside edge of the shoulders a bit too so I don't get lots of squeeze out to clean around the show edge, I guess the clearance at the bottom is actually squeeze in....unless I use so much glue that it has to come out. The. It's just a mess.
"A good miter set up is like yoga pants: it makes everyone's butts look good." Prashun Patel
[OP]
Contributor
How much glue, and do you brush it on the tenon, mortise, or both?
Scott Vroom
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.
Member
Scott i like to add glue as a lube to both parts. Here is how we do it.
Last edited by jack forsberg; 03-06-2015 at 6:44 PM.
jack
English machines
Moderator
What kinda glue are you using, Jack? Mine would have skinned over by now! LOL
Member
type III not thinned with water chris
jack
English machines
Contributor
Scott, it depends, but usually I leave about 1/32" gap at the bottom of the mortise. I also, score the tenon so the glue can come back up if it wants to. I mostly use loose tenons so this is an easy process; I just run them over the TS blade in a couple of spots to create shallow score lines. And I also put glue both in the mortise and on the tenon, using a brush or Rockler silicone paddle. It doesn't take much glue, but I want to make sure both surfaces are pre-wetted to better assure a good bond.
John
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