Thursday, July 22, 2010

Musings on the workbench

My SU pic in yesterday's entry probably simplified things too much. Great are the possible variations on the theme - hey, it's me, of course it's more complicated. Here's how the thought process is going. Sort of. Much edited, cleaned up and most of the the "Aaaargh, help me" bits removed. Some may creep in though... See if this makes any sense to you.

Firstly, what do I want in this bench? Normal people work out what they want to do with it and then pick a design accordingly. In this case, obviously, things are a bit different. The raison d'ĂȘtre for this workbench is the Emmert vice, and that is my primary consideration. Thus, criterion numero uno:

1. It's a bench for The Vice.

That narrows it down more than you might think, but we'll get to that.

Secondly, I only have working room for about 5ft, or 1.5m or thereabouts, of bench length. I could make it shorter and a dedicated Emmert Station, but see point four. Or I could make it longer, but then I wouldn't have room round it to be able to use it. Plus experience shows that walking into the corner of a bench every time you step through the door of your w'shop tends to result in falling very much out of love with said bench quite quickly. It's also got to be next to a wall, so the classic 2ft or 600mm width is also pretty much set. With my height and the pinkie test, it'll also be around 32-33" high.

2. It's overall dimensions will be 5ft x 2 ft x 2ft 8in.

Thirdly, it occurred to me that having a smaller bench could also result in some benefit in the future. At some point I will inevitably be down-sizing and it could be that, despite the best will in the world, the Behemoth Bench just won't be able to fit into a bedsitter... So it makes sense to make this bench usable for actual woodworking purposes. But more importantly, it makes sense to make it moveable out of the workshop. Thus, a knock-down design would be desirable. It'd also make the construction a little more feasible for just me, rather than having to call in the troops to help me lift the thing.

3. Knock-down design.

4. Workbench suitable for general hand tool woodworking tasks.

At the moment these seem to be the main points. Just for kicks I'd like to make it different from the Behemoth too; round dogs, not a traditional tail vice, etc, but none of these are worthy of a particular point. Anyway...

#4 clashes with #1 more than you might think. Current workbench thinking has it that you should have the legs of your bench in line with the front of your bench to provide more clamping surface. It makes sense, it's not something my current bench has, and it's very of-the-moment. Or very-of-the-18thC, depending on your view. I'd like to do it. But notice in this sketch how, in order to accommodate the rear jaw without hitting the legs you need an overhang of around 18" (450mm).


Now I suppose I could put the vice inside the left leg, but I fear two things. One, that access to the tilt lever under the bench, on the lefthand side of the vice, will be restricted and it'll become a knuckle-skinning operation. Two, that some of the advantage of the vice being able to hold things at extraordinary angles will be lost if said workpiece is restricted by hitting the leg. So, for preference, I'd like to remain outside the leg and stretcher area.

However, if we disregard ancient/modern thinking and have inset legs like wot I'm familiar with, it seems to me you can drastically reduce that overhang - thus increasing the base size and therefore the stability:


I'm currently torn between the two. Naturally the excellent suggestions of having another vice on the other end to balance it up a little is quite appealing, but two problems. One, because of #3 (knock-down design) there'll be a top stretcher on the end leg assemblies, rather complicating fitting a face vice as a tail vice. At least without bringing in further complications of some overhang at that end too. Secondly, there's one thing worse than walking into the end of a wooden workbench top every time you step into the w'shop. Yup. It's walking into a chunk of metal vice every time you step into the w'shop. Tail vice duties are likely to be taken up by a Wonder Dog or other cunning gizmo dreamt up by the Veritas Elves. Something that doesn't jut out much anyway.

On the other hand, I could see if I can at least find that vice that's knocking about somewhere...

So where was I? Oh, yeah. Undecided.

Then there's the top. Now my plan is to laminate up strips and aim for something as close to 3" (75mm) thick as possible. But how in hell am I going to lift that? So then I was wondering about the two-part top variety. Bob Lang makes a pretty good case for same with his 21stC workbench. But then again, I could make it two parts without a gap maybe? Or make the front bit heavy and laminated, and use the old trick of having a thinner rear section. Or...

See what I mean? The angst, folks. The angst.

Then there's that nagging option to fit the darn thing to the Behemoth after all, and just hope it'll fit in the bedsit. No-one seems to like that idea. If I said I'd then use the SYP to build a bench anyway, would it get any votes then? ;)

6 comments:

  1. I think you're missing a point. YOU'VE GOT AN EMMERT.

    Tthe design features of simple benches (Roubo's, Kirbys) are intended to work in conjunction with clamps, and wedges, and planing stops, and stuff like that.

    BUT YOU'VE GOT AN EMMERT.

    Therefore your work holding requirments are primarily addressed BY THE EMMERT.

    Of course, very few workbench designs (or design books) are very helpful in this regard.

    A book (or chapter) titled "how to design a workbench for your EMMERT" would have a narrow readership...

    BugBear

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  2. Remind me again, BB - what have I got?

    Yes, you're probably right. But it can't do everything. Can it? I mean for the simple stuff it's still essentially just a face vice, right? Wrong?

    You're going to remind me that How Would You Know, I'm the ONE WITH THE EMMERT, aren't you...

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  3. Why not mount the emmert on the end? That way you can use the dog along the whole length of the bench. But it can create some mounting issues with the legs.

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  4. Putting the vise up close to the leg like the second picture is what I did. It doesn't get in the way of the action of the vise. It also moves the center of gravity (and the disturbance of the earth's magnetic field caused by that chunk o' iron) more in line with the leg.

    You only have to have enough space for the beam to clear. I probably could have moved an inch or two closer to the leg.

    Don't even think about putting it inside the legs. It is hard enough to get to the locking levers for my humble knock-off with a 1x4 skirt around the bench edge.

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  5. Who says that all four legs have to be the same size? It would involve a little carving but if the front left leg (where the EMMERT vice! is) was wider and maybe a little deeper you could still put the vice beam right up against the side stretcher and carve out what you needed to from the leg. The tennon on the leg could still be the same size as all the other legs, it would just be offset to accomodate the carving needed to bring the vice up against the side stretcher.

    A Canuck lurker

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  6. One of my benches is almost what you are thinking of building. I used a scaled version of the Kirbys design so its 4' 6" long. This design has no stretcher near the top so the vice can go anywhere. Mine, one of the Emmert rip offs from far east, is placed inside the leg, far enough to allow me to get to the levers.

    Two reasons this a good idea, if I plane with too much force the short bench can tip just like your pictures. Second if the vice is close to the end a large plane like a No7 would bump into the wall at the end of the bench. If there is no wall at the end why not make the bench longer.

    I am sure there are more musings, good luck,

    Don

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