? on mortise and tenons

[Brent Grooms]

Ok, I am looking at the plans for the base of my workbench. It uses mortise and tenon joinery. Really straight forward right? Unless you really have never built anything with them nor have any practical experience with them.

My question is... can anyone in practical terms tell me what the proper fit for assembly of one of these joints?

[Robert Goodwin]

Here is a video of the ins and outs of MT joinery.

http://www.woodworkingonline.com/2006/11/15/video-podcast-2-mortise-tenon/

[pat warner]

Question a little vague. Fit to me is = allowable slop and that, (for glue to do its thing) is ~.003"

Now how you get there is another matter. Some G-2 at the mortice link. (http://patwarner.com/router_morticing.html)

[Hank Knight]

The fit should should be snug but allow you to push the pieces together by hand with no slop or wiggle. If you have to use a mallet or a dead blow hammer to pound the joint together, it's too tight. Glue will lubricate the joint so a tight, hand-fit joint will go together much more easily on final assembly.

[Brent Grooms]

Thanks Hank, that was the explaination I was looking for. Pat and Robert, thank you for the links... going to do a little reading...

[Tim Sproul]

Part of the equation is also the wood you are using. Softer and more compressible woods can handle very tight joints...joints that have to be slammed closed with a mallet. Very dense and incompressible woods need a wee bit of slop for the joint to go together without the mortised member splitting.

Because the joints in a workbench are likely going to be stressed a lot - both in the amount of force and in the frequency - you should consider mechanically reinforcing the joint by wedging or drawboring.

[Peter Stahl]

Brent, sorry for jumping in on your thread here but it's still about M/T's. Does anyone use a rabbit/shoulder plane to adjust their M/T joints? Brent when I made my last M/T joints some were a little tight and needed to pull them together with my clamps. What size or type of plane do you use?

[Allen Bookout]

Here is a video of the ins and outs of MT joinery.

http://www.woodworkingonline.com/2006/11/15/video-podcast-2-mortise-tenon/

Robert,

I'll get you for that!!!!! Out of curiosity I downloaded and watched the video and am now exhausted. The guy spent one hour and fifteen minutes trying to make one mortise and tenon joint and it would not even fit. Split out the end trying to force it in.

I am sure that I am going to have nightmares tonight as a result of this video.

Allen

[Seth Poorman]

Brent, sorry for jumping in on your thread here but it's still about M/T's. Does anyone use a rabbit/shoulder plane to adjust their M/T joints? Brent when I made my last M/T joints some were a little tight and needed to pull them together with my clamps. What size or type of plane do you use?

Hey Peter - I also use a shoulder plane , I use my stanley 1" and a Record 73 for the larger Tenons. I cut my tenons a hair large and use the the shoulder planes to make fit just snug...;)

[Tim Sproul]

when I made my last M/T joints some were a little tight and needed to pull them together with my clamps.

IME, I've found using abrasive adhered to a flat block of wood is the most efficient for fine adjustments. 80 or 120 grit Norton 3x abrasive can take a m/t that needs a dead blow to a hand press fit with just a pass or few over the tenon.

[Brent Grooms]

FWIW, I am planning on drawboring the legs to the trestle feet and to the top support as an assembly then probably using wedge-locks on the stretchers. all of my base assembly will be using my stash of 3/4-4/4 oak. It will be more work in laminating it all but I have it and alot of it.

[Alan Turner]

Brent,
For your application, you might consider using wedged tenons for the leg to sled foot connection. About a 3 degree wedge is good for a deep mortise (3" or so). For the leg to top stretcher, a bridle joint (basically an open mortise and tenon) is effective and easy to cut.

For the stretcher to leg assembly, one way to do it which is strong and easy to cut is a very shallow and large mortise, and matching tenon. Maybe 3/8" deep is all, with a 1/4" wide shoulder. Then use a captured nut and bolt to draw them tight. This has the advantage of permitting disassembly, and retighening with seasonal changes. A 1/2" x 6" hex head bolt can exert a lot of pressure.

[Robert Goodwin]

Robert,

I'll get you for that!!!!! Out of curiosity I downloaded and watched the video and am now exhausted. The guy spent one hour and fifteen minutes trying to make one mortise and tenon joint and it would not even fit. Split out the end trying to force it in.

I am sure that I am going to have nightmares tonight as a result of this video.

Allen


Ouch :eek: I have not finished wathing the Video yet. I started it here at work, but then work got in the way. That stinks. I guess I should have watched the whole thing prior to submitting that link ;)

He did seem a bit unorganized, but I took that as him not being confortable in front of the camera.

Rob