Bench building questions: attaching top to base? mounting tail vise on a short bench?

[Fitzhugh Freeman]

I'm building a short (5.5 foot) bench - the top will be two pieces of douglas fir that are finally dry, each 3" x 14" by 5.5'.
While waiting for the wood to dry I made the planes and carved a large wood screw for a leg vise. I'm knew to woodworking and am doing this all by hand so I can learn and enjoy the process. Planing the top by hand is a huge task but I've finished one side of each board.
I want to make a base along the lines of the 21st Century workbench. In any case, I need to be able to knock it down occasionally, want to avoid lag bolts and other metal fasteners, so I figure a very sturdy separate base and a top that is just held by loose tenons, pegs, or the like will be best. I was recently given a veritas twin screw, and since I want to use the wooden screw I made for the leg vise I'll use the twin screw as an end vise.

However, the combination of a knock-down, short bench with little-to-no overhang and the tail vise are giving me fits.

My concerns:
I'm confused about how to mount the tail vise so that A) the different grain direction of the inner jaw and the two top pieces don't cause problems with seasonal changes (or if that even matters here in California) while still being strong enough to handle the forces trying to pull the vise off when using it with bench dogs, and B) how to design the base so the vise screws don't interfere with the upper rail while still having a good way to attach the top to the base.

For the latter, I'm thinking I could either lower the right stretcher so the screws go over it, or have a tall stretcher with holes for the screws to pass through - that would mean I could still have the tenons or pegs for the top in the rail.

One more thing:

I actually have three pieces, and they'll be closer to 2.5" or even 2.25" when I finish planing out the wind from the portable sawmill they came from.
Three pieces is an odd set, I'll either make a short bench with just two (as above) or cut the third in half and stagger them, so that they look like this from the top:

OOOXXXXXX
XXXXXXOOO

where OOO = the short pieces and XXXXXX = the two long pieces. A short bench is not bad here - very limited room here - will using the three that way work? Either way, how should I best join the slabs? Any feedback or other ideas?

Thanks for any suggestions!

btw, I know I could have saved endless time building a router jig, or just finding someone with a planer, but this way is much more fun.

[Andrae Covington]

If it helps, you can have a larger overhang on the side with the tail vise vs. the opposite side. The bench doesn't have to be symmetrical. At some point the cantilever would be too great but I doubt it would be an issue in this context. Take a look at John Donofrio's recent thread (http://www.sawmillcreek.org/showthread.php?196953-Looking-for-opinions-suggestions-for-dogholes&p=2034718#post2034718) for a picture of what I mean, although his top is about a foot longer than yours.

I don't have a tail vise, so maybe someone else can chime in on the best way to attach it and deal with the upper side stretcher. Note that John's bench has a "breadboard" end across the top, I believe this is what most people do with a twin-screw end vise.

My workbench top is held to the base with a couple 3/4" dowels that stick out of the front legs into the top. Gravity does the rest. It works fine, except for one issue: over time, as changes in humidity make the wood move, the front edge of the top and the front faces of the legs have gone out of alignment, ~1/16". The advantage of the traditional roubo sliding-dovetail-shaped tenon (http://www.popularwoodworking.com/techniques/joinery/a-j-roubos-sliding-dovetail-tenon-joint) method is that it locks the front edge of the top with the front faces of the legs, so they move together.

250612

The 21st Century Workbench uses horizontal keys on the long lower stretchers. I used vertical keys (aka tusks) on mine. Either way works fine as a knock-down style that doesn't use metal hardware. Once or twice I've gone around and whacked the keys again to tighten things up. The 21st Century bench has the addition of wide upper long stretchers with half-lap dovetails; this is probably a good idea considering the relatively small size of the legs.

250613

[John Donofrio]

I would vote for the tall stretcher with holes or slots for the screws as opposed to moving the whole assembly inward to provide enough room for the screws. I think it might be a bit too easy to tip if heavily leaned on otherwise. You need a good footprint to keep it stable.

As for how to mount the inner jaw/end cap, maybe a sliding dovetail could help here. I would certainly not ignore the movement, regardless of your location.

[Fitzhugh Freeman]

Thanks both of you.
Was away for some days after posting, finally back to catch up.

Andrae, I'd thought of using dowels in that way but always worried they would not hold up. Seeing the photo I realize that was a silly concern. I'm not often going to be putting huge forces across the width of the top and the base would likely just slide before the pins broke. And if they do? I'll replace them. I actually kinda want to hold off on dovetailing the legs roubo style and use dowels instead so I can come back and replace the legs with roubo legs later, once I have more experience (and tools, and money for nicer wood). I didn't mention it because I know I won't actually do it, but that's part of the reason I want a minimally invasive means of attaching the top. If the legs and the top end up out of line I'll tip it over and plane it flat, if possible and necessary. I hadn't considered that issue, thanks for pointing it out.

John, I hadn't seen your thread - inspiring bench! Right along the lines of what I'm aiming for so I'm happy to see it done nicely.
Some questions:
How did you attach the inner face of the end vise?
How did you choose to attach the top to the base?
Sliding dovetail, hadn't thought of that since I'm not planning on an apron. Would it run the width of the bench?
Please post more photos of your bench!

OK, back to the warm room in our house. I lied when I said we don't have seasons here in California. We do, but usually so mild our landlord didn't insulate the house and we only have a wall heater in two rooms. Living room is 41, just above what it is outside. Luckily the bedroom is one of the heated rooms and the work room is the other!
Thanks again.

[Rodney Walker]

If you decide to join the short pieces end to end to get a longer bench use at minimum a half lap joint on the ends. I would also add a full length board on the outside of each side and maybe one in the middle to give more support. End grain joints are the weakest and special care needs to be taken with them. Especially on something that's going to be taking a lot of stress like a workbench.
Rodney

[Fitzhugh Freeman]

Rodney, good point. I haven't really thought through adding them and it could be really problematic if done wrong. If I do add them I figure I'll make it a solid top - not split top - and have the short piece on the front on the right end of the bench and the back one on the left. That way I can use the long grain along the middle to do much of the work but I think you're quite right, it wouldn't be near enough. I'll probably do a split top with just two long pieces for now. That way I can remake it and extend it later if I find I really need a longer bench.

[John Donofrio]

I used 5/16" Spax screws to attach the end cap, or inner jaw, to the two top halves. I used 1/4" Spax screws to attach the top to the leg assemblies. I didn't bring that up since you stated you didn't want to use any metal fasteners, which I understand. For me this bench is purely utilitarian, although I wanted a 'nice' workbench. It also provided me an opportunity to learn some new techniques. It has been a fun, albeit, challenging build. I'll be updating this thread (http://www.sawmillcreek.org/showthread.php?196969-Post-production-roubo-build-thread)with more posts soon that show pics of the leg assemblies and the end cap/tail vise assembly.

Also, thanks for the compliments.

[Fitzhugh Freeman]

I missed the reply notification in my email, thanks for replying.

I see nothing wrong with using screws, I'm aiming at avoiding doing so simply because I want to get as much practice building the bench as I can. I enjoy the process more then the result when working on any project. I'm wrapping up a couple of other projects first - my new years resolution was in the form of a prioritized list of projects to work down so I don't jump between too many and get too few finished.

I just took a look at your post-build thread: wonderful work! I just learned about the chain guided leg vice the same day I posted the above question, and now I see you've used it. What an elegant design!. I'm glad to be able to read your thread - for example the worry about the need to prevent the leg vice from forcing the top out of place. I'd rather read it than learn the hard way.

Thanks

[Adam Cruea]

I meant to reply to this. . .

Don't know what you would want to do, but I just made a 3.5" thick top with a 6" apron all around. The end vise/end apron is attached with half-blind dovetails, and the top of my bench attaches to the base with dovetails, too.

Just a thought.

[mike holden]

"The advantage of the traditional roubo sliding-dovetail-shaped tenon (http://www.popularwoodworking.com/techniques/joinery/a-j-roubos-sliding-dovetail-tenon-joint) method is that it locks the front edge of the top with the front faces of the legs, so they move together."

Actually, that just moves the problem of the humidity induced mismatch to the top surface. The ends of the legs stick up!
Of the two, the face mismatch is easier to deal with than the top mismatch. TANSTAAFL!

Mike

[Jessica Pierce-LaRose]

I don't know - even as annoying as it is to plane end grain, if the legs go proud, I'd just plane 'em down, which seems easier to me than trying to get the face of the leg/bench thing back in line if for no other reason than I wouldn't have to plane sideways or turn the bench.

[Andrae Covington]

I don't know - even as annoying as it is to plane end grain, if the legs go proud, I'd just plane 'em down, which seems easier to me than trying to get the face of the leg/bench thing back in line if for no other reason than I wouldn't have to plane sideways or turn the bench.

Yeah that wasn't fun. First I had to wrestle a big sheet of plate steel up to the wall behind the bench, then put on some electromagnetic boots, and then I could finally stand sideways and plane the front of the workbench. (;)) Joking aside, planing sideways was awkward. When it moved again after a while, I gave up.

I suppose one approach would be to stop the tenons short rather than run them all the way through to the top.