Tenon sizing - rule of thumb?

Re: Tenon sizing - rule of thumb?

Richard Gillespie

>I was taught the 1/2 the thickness rule and use it. 1/3 sounds too thin. IMHO the strength of the joint depends on the tenon not fracturing at the shoulder.

That's my $0.02 and I give change.

Re: Tenon sizing - rule of thumb?

John, NY

>Thats what I use too... 1/4, 1/2, 1/4

John

Re: Tenon sizing - rule of thumb?

Derek Cohen (in Perth, Australia)

>I say use your common sense. It depends on the stresses involved on the joint, and the size of your available drill or router bits/mortice chisels. Sometimes I approximately apply the thirds rule, and at other times I go (approximately) 1/4 on the shoulders and 1/2 on the tenon. What about the length of the tenon? You haven't questioned this. Thirds as well?

Regards from Perth

Derek

I go...

Ted Owen, Pittsburgh

>a little more than 1/3, but well less than 1/2. For 3/4" stock, the tenon often is about 0.3", or 10 millimeters.

Normally I like hundredths inches, as my mind tends to think in percentages. But tenons are determined by which mortise chisels I own, and my favorites are in millimeters.

Best, Ted

Quick - what's 1/3 of 0.5" stock?

Mbatarga

>If you're using 3/4 stock, the 1/2 or 1/3 rule work fine, as you can use standard router bits/mortise chisels to get your 3/8 or 1/4" mortise. But if you are using 1/2 stock, where are you going to get a 0.33" router bit or chisel?

In almost all cases, if you go by the rule of 1/2 the stock thickness to determine the tenon thickness, you don't have to worry about figuring out non-standard dimensions.

Re: Tenon sizing - rule of thumb? *LINK*

Bill Houghton, Sebastopol, CA

>Seems to me there was a recent thread on this. Oh, yeah, here it is.


Oh, the tenon bone connected to the mortise bone..

Re: Tenon sizing - rule of thumb?

Charles

>Determined my what size mortise chisels you own. One-third, the perennial favorite, is fine.

I was taught to use the...

Scott Burr in Ben Lomond CA

>1/3 rule dictated finally by mortise chisel width.

I have a good teacher, on video that is... Jim Kingshott.

Disparate admonishments??

Jack from Maine

>I understand everything you are trying to say but I can't make sense out of that two word phrase. I'm not sure what disparate means (different?) but I thought to admonish was to find fault.---don't mind me it's been a long day.---Crackerjack

Re: Disparate admonishments??

Bill Houghton, Sebastopol, CA

>Disparate: "completely distinct or different in kind; entirely dissimilar."

Admonishment: you're correct that the connotation of this is usually negative, but it can mean "to counsel against something." Many people use it, as Scott does, to mean "instructions," particularly in the sense of "whenever you do this process, ALWAYS do it this way."

4mm - chisel easily available

Andrewf in Australia

>This is an off the shelf item.

Cheers,

Andrew

Re: Disparate admonishments??

Jack from Maine

>Thanks for clearing that up for me.Sometimes after a long day my mind is incapable of flexible thought.--I start my days every day by doing all the word puzzles in the paper.It's like stretching exercises for the brain,but tonight I doubt if I could handle the tv guide puzzle.---Crackerjack

Re: Tenon sizing - rule of thumb?

Eric Lund

>The rule of thirds is based on removing the least amount of material from BOTH pieces. However, that value is only an approximation. The actual value is based on the width of your mortise chisel that most closely appromimates the rule of thirds.

Cheers,

Eric

Huh?

Sandor in Boyds, MD

>When you account for all material removed (M&T), don't you remove the equivalent to the entire board thickness regardless of the tenon width?

Re: Tenon sizing - rule of thumb?

Scott in Douglassville, PA

>See that - searching on the wrong component. Thanks Bill.

Thanks, everyone...

Scott in Douglassville, PA

>Good input, all. Ellis and Bill Hylton had some good, engineering-type input on the general board, as well.

FWIW, my selection is also being dictated by convenience - I have a 3/8" router bit (egad - did I say that?!), so that's what I'm doing (actually, what I did, as they're all done). The M&Ts on this are for a drawer web frame, runners and dividers fitting into dadoes in the cases sides. The tenons aren't seeing the same shearing forces as in, say, a door. I just got to thinking, and thought I see what y'all do.

Thanks again.

Scott

Re: Huh?

Eric Lund

>I guess I should have been more specific. When I say the least amount, I realize that the total is equal. What I mean is that taking the least amount from one that also takes the least amount from the other. The rule of thirds supports this. If you take 1/2 from one, then that leaves weak shoulders. Of course, if your mortise piece is much larger than the tenon piece, then you can adjust to make a stronger tenon, because you don't have to worry about weak mortise sides.

Cheers,

Eric