Questions for those whom have built a Roubo relating to vises and split vrs solid top

[Patrick Walsh]

I am about to embark on my first real bench build. I hope to order the lumber this week. For practical purposes i think the top will be ash. The legs, stretchers, chop, bread board end and plane stop will be cherry and the real splurge. I have yet to decided if the bench will have square dogs and a end vise of sorts or just round dog holes and a couple hold fast.

The bench is going to be a Tank! The dimensions will be a finished 32"W x 10.5'L x 32H. The top will be 6" thick and the legs will either match @ 6x6" or 7.5x7.5" mostly dependent on how i order my lumber. I am buying 12/4 stock for the top and considering the same for the leg laminations. I know the thickness of the top and legs are overkill but i think it will yeild a amazing bench all said and done and i really could care less about being practical. Im not really the practical type when it comes to my woodworking.


So the questions mostly relate to a end vise. I would like to use a BenchCrafted style end vise in conjunction with square dogs. I hope to aquire my hardeware from Maguire Benches i think out of the UK as i much prefer the finish on their round hand wheel and end vise. Lets hope they still make them or imay be sending some BenchCrfted stuff out to be plated.

This leads me to question number one. Is there any reason why i cant do the double tennon dovetail joint found on the traditional Plate 11 Roubo with a end vise and square dogs. My concern is the the dog holes and vise assembly conflicting with each other. I cant really see why they would anymore than a non through mortise and tennon. I assume this should not be a concern. My question is mostly derived by not finding many square dog benches online with the through tennon style joint and a end vise. Just about everythink i find follows the Benchcrafted plans with the square dogs and non through tennon.

The second question is with regard to the split top. I dont plan on purchsing any plans to build this bench. The joinery is as straight forward as it gets. Im sure it will be time consuming and i will have more than one tentative moment but i dont see a need for plans beyond my own drawing.

So the split top, again i dont find many if any split top benches with the through tennon style joint for the bench top and leg. I get that the through joint can not be taken apart and that the non through joint as layed out in the Benchcrafted plans can be disassembled for variuos reasons.

I am not concerned with being able to take my bench apart to move or flatten. I am more concerned with it being a tank. As far as i can tell the split top benches as built per the Benchcrafted plan attache to the base via the " non through " mortise and tennon on each leg then a lag bolt from the underside through a stretcher in the base assembly. Does anyone see a reason why i could not build my bench with the through mortise and tennon and split top design per the Benchcrafted plan with the addition of the through tennon.

One other thought is to attach both top pieces during the tops glue up with blocks spaced every so often to accept a stop thus creating one solid top.

I am probably overthinking this. I do however want to get these last details sorted before i place my lumber order as it is going to be pricey and i dont want to order any uneeded lumber as the money being spent is staggering for a bench!

I am pretty excited as i have been wanting to build this bench for a couple years. It should be great fun and satisfying. As nice as it will be to have this bench built i will miss all the daydreaming and planing.

Thanks in advance for the help.

Patrick

[John Sanford]

Yes, you can do the "classic Roubo" double through tenon with a split top. If you do, then you wouldn't even need the lag screw. The main purpose of the lag screws is simply to keep the top slabs down when there's a substantial weight on one end of the bench, plus if you decide to move the bench by LIFTING on the top. I have built a Benchcrafted based Split Top Roubo and haven't yet put the lags in. I don't plan on standing on the ends, so I'm not terribly worried about the top lifting off. With double tenons on a bench as long as you're considering, I don't see that there's much risk of the tops lifting off. I wouldn't recommend a Sumo wrestler giving an Irish step dancing demonstration on the ends of the bench, but beyond that, you should be good. And if, for some truly bizarre reason (performance art?) you DO have a Sumo wrestler give an Irish Step Dancing performance, you can simply run the lags in and order in the beer and sake. I would not glue the top down, doing so won't be of any real benefit and could bite you in the keester some time in the future.

As far as the double tenon and dog hole interference, I suspect the reason you don't see any is because the dog hole will reduce the mechanical strength of the joint. Whether such reduction actually matters is an open question. Also, the combination substantially complicates the layout and cutting of the square dogholes. I't would certainly be doable, but would it actually be worth the trouble? For round dogholes, there's simply the question of mechanical reduction, plus also the possibility of binding the doghole with seasonal wood movement. Not that that would actually be a big problem, as all you'd need to do is run your drill bit into the hole to ream it out and voila, problem solved.

There is a video out there on the web of a chap over in the UK who has an excellent method of making his double tenons for the legs. Rather than cutting them out of a single massive piece of stock, he glues up a three piece lamination, with the center piece being shorter, and voila, all he has to do is cut the angles on the dovetailed tenon. That can actually be done before the lamination. Seems a heckuva lot more convenient than cutting the tenons.