LumberJocks

Roubo leg - sliding dovetail & tenon question

  • Advertise with us

« back to Joinery forum

Forum topic by Bugnurd posted 12-10-2014 12:09 AM 1480 views 0 times favorited 4 replies Add to Favorites Watch
View Bugnurd's profile

Bugnurd

105 posts in 1057 days


12-10-2014 12:09 AM

I just noticed that in the plan I’m loosely following for a roubo bench, it calls for a small shoulder on the inside edge of the tenon. Is this shoulder absolutely necessary? Will leaving it out compromise the integrity or stability of the bench? I could glue a 1×6 to each leg for the shoulder, but I’d rather not if it doesn’t need it. I just don’t know enough about joinery to decide. What do you think? This is where I’m at now…

-- Marc -- Worcester, MA


4 replies so far

View BubbaIBA's profile

BubbaIBA

383 posts in 1843 days


#1 posted 12-14-2014 01:34 PM

A couple of thoughts, one addressing your question, the other unsolicited advice.

The shoulder is where the M/T joint gets a good part of its strength. As you have a substantial shoulder between the tenons an additional small shoulder would not add a lot of strength but it would cover up a rough mortice.

My unsolicited advice deals with the through tenon, I know it was traditional in older French work benches but from a strength stand point there is nothing to gain over a housed tenon that has been either “pinned” or even better draw bored. Because wood moves and the through tenons are presenting end grain there can be significant differences in movement of your slab and the tenons requiring more maintenance to keep the top true. .Also when doing maintenance on your slab with through tenons you will always have four areas of end grain to deal with.

I’ve built a bunch of work benches all with housed and pinned M/T joints to attach the slab to the base and none have ever had any stability problem. BTW, because my bases are put together using draw bored M/T joints the only glue used is in the laminations. If you are building the bench to work on, not to meet some esthetic idea I would lose the through mortices and go with pinned housed M/T joints.

ken

View JADobson's profile

JADobson

682 posts in 1577 days


#2 posted 12-14-2014 02:03 PM

Just remember that there is absolutely nothing wrong with meeting an “esthetic (sic) idea”. I hope every thing I build lives up to the aesthetic ideal I’ve set for it. Not trying to say that there is anything wrong with the advise Ken has given you but just remind you that form is just as important as function even in a work bench. So make it the way you want it to look. However, I think the issue of wood movement with through tenons is not that much greater than with housed M/T. My bench has housed M/T and I’ve noticed some movement. That is the nature of wood.

-- James

View Bugnurd's profile

Bugnurd

105 posts in 1057 days


#3 posted 12-14-2014 03:30 PM

Thanks for the thoughtful replies and advice. I’m not worried about hiding anything, especially since it would be under the top on the inside edge. I’m using mostly free salvaged 2 by softwood from crates for this, not some expensive hardwood, so I’m not worried a whole lot about aesthetics. I’m going with the thru tenons. Almost every operation on this build is a first for me, so pretty much any route I choose will be a valuable learning experience. Here’s how the tenons turned out.

-- Marc -- Worcester, MA

View ElChe's profile

ElChe

630 posts in 803 days


#4 posted 12-14-2014 04:54 PM

That’s looking mighty fine! Update the progress.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com