Designing legs of (not knockdown) Roubo with current Benchcrafted hardware

[Hugh Howard]

I am getting started on a Roubo.  I'll build it fairly close to Marc's plans, although I'll use the crisscross on my bench which didn't exist when the guild project came out.  I retrofitted it to my old bench so I have a pretty good sense of what it takes, but wanted to make sure my current idea makes sense.  I've also seen Marc's retrofit video, but thought it was worth getting everyone's perspective on how to do it if not as a retrofit.

I am not doing a knock down or I'd do it as BC suggests.  I haven't seen plans for a drawbored non-knock down leg plan.  The thicker rail they suggest is so that the bolt can pass behind the crisscross, but that detail doesn't come into play when you aren't building a knockdown bench.

The guild plan has a leg that is 5 3/8" across and rails with 2" tenons. 

The groove for the Glide chrisscross is 1 3/4 across. 

Centered on the leg this leaves (5 3/8 - 1 3/4)/2 on either side or 1 13/16.  This is just under 1/4" too little space for the 2" mortise for the tennon.

Should I

a ) build a leg that is 1/2" wider than the original plan leaving 1/4" on either side of the groove and cut the front rail down by 1/2" (for symmetry both the front and rear left legs could be done like this)

or

b ) just let the tenon be 1 3/4" long instead of 2"?

or is another plan entirely in order.

Also in either case is there any problem with the mortise bottom opening into the groove?  I assume this isn't an issue since the shoulders of the rail will keep the tenon from pushing into the groove, but, of course, I might be misisng something.

 

 

On a different line of question (perhaps for its own thread?) I often see people advise that wood should be milled and then used as quickly as possible so it doesn't warp.  I recently saw an article on work benches that seemed to give the opposite advice for the slabs.  It said to mill them and then give them a couple days to acclimate before gluing them up.  What do you think? 

 

Thanks!  Hugh

 

[Trip]

==>mill them and then give them a couple days to acclimate before gluing them up

Best practice is to mill in two stages... Stage one: mill to approx dimensions and let the components sit for a few days and do what they want to do (it's best to sticker them)... Stage two: mill to final dimensions, cut joinery and assemble on a fairly tight schedule...

As for the Roubo, I built a non-breakdown base... Let me noodle on your query overnight...

Cheers..

BTW: Painter's Chair?

[Hugh Howard]

Thanks for the advice hhh.  Silly question - what does "Painter's chair" mean?

 

It is lucky I don't do this for a living.  I always massively underestimate how long things will take.  The milling question is moot in the sense that I thought I'd be able to take the morning to get a straight edge on 3 boards, rip them to about 5 inches, surface 5 pieces and then decide if I wanted to do a glue up for the front section in the morning.  Instead, I got a straight edge on 3 boards and one badly done rip and that was about all I could fit in (Turns out both my tablesaw and band saw are a little under powered for 8/4+ maple stock so it is slow going and there will be no wood that is under acclimate since I tend to get into the shop at best once a week.) 

[Trip]

Not a silly question... Hugh Howard is an unusual name. There’s an architectural historian of the same name. One of his more well-known texts is, The Painter’s Chair.

 

I'll take a look at my Roubo and see if I can answer your other question...

[Hugh Howard]

Alas, I can't claim to be a famous architectural historian (or apparently even one who knows about them)!

[Tom Cancelleri]

I put my tenon right into the mortise of the leg with the criss cross cavity. I then used a top bearing flush cut bit to flush the tenon to the wall of the criss cross cavity. Worked just fine. No worries about strength. I draw bored my base together, the reason for doubling up the front and putting the bolt behind the criss cross is because it would be in the way. 

[Hugh Howard]

That is great, it makes sense, but it is nice to hear confirmation from someone who has done it in practice and not just in theory!

 

An update on my progress - I finally got the boards mostly milled and the front section glued up.  It sure took a lot longer than I expected, but so far so good.  I get better results from cauls than biscuits (I don't have a Domino and my biscuit joiner never seems to leave things well aligned) and the cauls look like they left me with a reasonably flat surface.  It will take some work to get it ready or the planer, but not an insane amount.

I bought the rough lumber thinking I'd build the bench some day later, but then there were enough BF that they took over the (small) shop, and it became clear that I couldn't do much of anything before doing something about the bench so my goal is to get the two top slabs glued up and then the shop will be under control again and I can decide if I finish the bench first or start in on a piece of furniture that I originally intended to build before the bench. 

[Hugh Howard]

By the way, I realize mostly milled is ambiguous.  All the boards are just over 4.25" thick, the front section is at the right width (in fact somehow I ended about 1/32 - 1/64 below the target - not ideal, but not catastrophic) and the back section looks pretty good in terms of being straight and is about 1/4" over in width and will be milled down the last bit the day it gets glued up.  Right now it will work with just 6 boards, but if they don't stay square over the next couple days and require more milling I might have to use the 7th board that I'd love to save.  That said, they've stayed surprisingly stable so far so I'm optimistic.  If only I had more clamps I'd glue that section up today, too, but I have just enough clamps for one section at a time (and probably just enough shop time, too)!

 

 

[Hugh Howard]

Since I always enjoy pictures in other people's posts, here is the front slab, nothing glorious, but it makes me happy (behind it you can see the old workbench feeling jealous)...  I'll try to post shots as the bench progresses although in the next week or two that probably just includes the glue up of the back slab so this won't be a rapid process.  Given that I work slowly and don't get in the shop as much as I'd like, if I'm done before Marc's daughter takes her first step I'll view it as a victory.  If she is in college before I'm done we'll call it a loss.