Saturday, April 23, 2011

Building A Bench On Bench

In Roubo's Slippers, I fine-tuned the height of my workbench for planing. However, many other operations benefit from a higher work surface. Moxon's double-screw vise is one way to elevate and hold pieces for dovetailing.

I first stumbled onto the idea of a benchtop mini-bench last year on Alf's blog. She had built one based on Jeff Miller's 2005 Fine Woodworking article. Miller used veneer press screws to form a double-screw vise on the front. Alf used wooden screws she turned on the lathe and threaded with a threadbox. Either way, this adds the elevated work surface to go along with the vise.

Then I saw this one on Joel Moskowitz' blog at Tools for Working Wood. It's built by the Philadelphia Furniture Workshop, their version of Miller's design. You can buy either a finished one or the hardware kit (screws and clamp handles) to build one from Joel here; instructions for building a simple plywood base are here.

After debating back and forth which one to build, I decided on the last one. Miller's was a simple slab design, but I liked the PFW butcher block construction, as well as their base. I used standard veneer press screws, as Joel showed in the initial PFW version. Links for suppliers are listed at the bottom of this post.

The one technical challenge was figuring out how to get the long veneer press screws into the laminated top using hand tools. I didn't think I'd be able to hand-drill parallel 9"-deep holes straight enough. I thought about chiseling channels into the underside. I initially expected to fit the flanges for the screws to the front. Then it hit me: drill the holes one lamination at a time, and bury  the flanges in the first lamination.


Marking out the first rip for the butcher block laminations in a slab of 2x10 poplar.


Ripping the first piece. Since this board is flat-sawn, when I roll the pieces 90 degrees they'll be in quartersawn orientation for gluing up the top. The kneepad makes this much more comfortable.

Make sure your saw is sharp for this kind of work. Do yourself a favor and spend 10 minutes sharpening it; you'll save 30 minutes of heavy work.

In thicker stock like this, flip the piece frequently to keep the saw on track (mark both sides with the gauge). You can hold to within 1/32" of your line for the whole rip that way. Otherwise you're likely to find the back side of the cut has wandered by 1/8" or more, requiring a lot of work with the plane when you joint the edge for the next piece, and flatten the final glue-up.


Jointing the edge for the next rip. Notice the long-sleeve shirt is off, and the bandana is on. This is heavy ripping.


Cutting the pieces in half.


All the rough-cut pieces laid out to plan screw placement. Just barely visible, in addition to a cabitnetmaker's triangle, I've marked arrows on each piece showing which way the grain goes. They all need to be oriented the same way for planing once they've been glued up.


Carefully drilling the holes in the first piece. Each piece will serve as the guide for the next. For this piece, which will be the loose vise face, I used an 11/16" bit; the screws are 5/8" in diameter, so this allows a tiny bit of play. For the remaining pieces, I used a 12/16" bit. The extra tolerance will be hidden in the lamination, and allows for any error in drilling. The holes for the flange are 1", which required a large-sweep brace for extra power.


Chiseling out a mortise for the flange, like a hinge mortise. Notice the side ridges down its length; I ran a gouge down each side of the hole for them, then flipped the flange over and dropped it into the hole. Fitted into the mortise, the flange face was flush with the surface of the wood, so it wouldn't interfere with the glue-up.


Loose test fit. The rightmost piece is the vise face. You can see the flange buried in the second piece. The left piece will slide up the screw to be glued to the second, and so on for the remaining pieces.


With the screws threaded into the flanges and cranked in, checking the alignment of all the drilled pieces (the screws don't reach the back four pieces). Nice smooth action, no binding anywhere.

At this point, I removed the screws and glued up the assembly. I replaced the screws and adjusted the pieces in the clamps to make sure they continued to turn freely.

While this dried, I started on the base, using some scraps of Baltic birch plywood. It consists of two I-beams joined by a crosspiece. Each I-beam is made of three pieces, top and bottom plates with center upright. The center fits in dadoes down the length of the plates. The height of the center determines the height of the base.


Cutting the I-beam plates.


Scoring down the length of a plate for the dado.


Sawing out the dado sides. Because this is plywood, I switched between rip and crosscut saws for each ply. That kept the saws from catching in the alternating grains.


Bevel down, chiseling up chips for the length of the dado.


Still bevel down, running the chisel down the dado to clear the chips.


Now with bevel up and chisel flat, paring the dado floor smooth.


When I test fit a piece in the dado, it was too tight, so I widened it ever so slightly with a #79 side rabbet plane.


Test fitting a piece into the widened dado. A good snug fit.

Once the top glue-up had dried, it was time to flatten it. First I flattened the bottom side with a #5 jack with cambered blade, followed by a #6 fore plane. Then I did the top side.


Diagonally with the #5 across the rough surface of the laminations to take it down quickly and evenly. This produces rough chips.


After some diagonal passes with the #6, straight down the length. Once I was getting consistent full-length, full-width shavings, I was done.


Using a scraper to deal with some nasty reversing grain that tore out in one corner.


Trimming the end even.


Shooting the end grain.


Chamering all the edges.


Drilling dog holes in the top.


Testing for height. This will determine how I size the I-beam center pieces for the base. With a Gramercy holdfast dropped all the way down and clearing the bench top, this height just has my elbows at 90 degrees. That's a recommended height for carving, and should be fine for dovetailing.


Final assembly of an I-beam. Modern quick-change combination bits work fine in an old brace.


Installing screws with a Yankee driver. The white block is wax for the screw threads.


Setting the screw with the quick-change bit reversed to its driver head. Just be careful, because this produces enough torque to drive the screw right through, damaging the work.

Rather than attaching the base permanently, I installed threaded inserts into the bottom side of the top, and screwed knurled knobs in through holes in the base. Getting all the inserts to be in alignment is another challenge. I ended up having to enlarge a couple holes in the base with a chainsaw file so that everything went together well. But this allows me to build a shorter base to swap out with this one should I find it necessary.

The last step was to make leather washers to go up between the screw handles and the front vise face. Otherwise, with the screws tightened, the handles rub against the face. I initially made wooden bushings, but one cracked when I tightened the screw down on it.


Punching out a leather ring with a gouge.


The completed mini-bench held in place with more holdfasts, with a piece in the vise ready for dovetailing. I even went to the trouble of putting a couple coats of lovely Aged Olive color paint on the base (no, that's not the much-reviled 70's era Avocado color!). The top really looks nice. The photo just doesn't do justice to the quartersawn grain surface.

I tugged on the workpiece to make sure it wouldn't move while working. Everything held firmly in place. And when I say firmly, I mean rock-solid, like it was physically a part of the main bench. This should be a great back-saver, so I won't have to lean over my work so much.

Veneer press screws are available from
Rockler and Woodcraft. Threaded inserts and knurled knobs are also available from Rockler. Holdfasts are available from Tools for Working Wood; get 2 pairs, one to hold the mini-bench down, and one to hold the work down. (When you get them, wipe off any machine oil residue, then wrap sandpaper around the shaft and give them a spin to roughen them a bit, giving them a super grip in your dog holes.)

12 comments:

  1. Fabulous Steve!
    Looks like a great help for that aching back. Nicely built too!

    As I was approaching the end of the article, I was wondering where you got the veneer press screws, and lo-and-behold there were links. Thanks for those.

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  2. Steve,
    Looks great. We have in stock the screws for the bench - but they are not on the website yet. We changed the hardware slightly and it's a little slicker than before. They should be on the website soon.

    joel

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  3. Steve,

    I am impressed with all you are doing in the shop. I also envy you for you are able to make all the items I want to make. Great Job. Can't wait to see the shop. Let's talk about making some tools together.

    Fred

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  4. Thanks, guys!

    Joel, let me know when you have the screws online and I'll include a link.

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  5. Wow. that was a nice build to follow along with. Thanks for all the great photos.

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  6. The bench screws that Joel mentioned can now be found as the second item on this page: http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=PROD&Store_Code=toolshop&Product_Code=MS-BOB.XX&Category_Code=

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  7. Thanks, Bob. I've updated the post to note that the hardware kit can be ordered at the same location as a finished one from Joel.

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  8. Love your blog!

    A quick question about height: I have yet to build or use a hand-tool bench but am planning one now. I am pretty short - 5' 5" so the typical measurements are too tall for me. I have some metal sawhorses which do coincide with the "pinky" or knuckle rules. When I lay a board on them and imagine planing (using a block plane as a prop), it feels really nice, and I understand how the whole body can be used to push the larger planes. However, when I imagine holding a plane in a dado on the face of a board, this seems too low, I have to stoop over a bit.

    I realize its better to make it too tall and cut it down later (though your slippers seem just fine to raise it) but what I could really use is an example of what an experienced woodworker finds a comfortable measure. For example, should planing be the "benchmark"? Or is chiseling more important? Which ends up being more taxing, physically? Which tasks actually end up happening the most frequently? Obviously experience provides the answer but this detail makes it very overwhelming for a beginner. Ideally we would all apprentice somewhere for a while before designing our own workshops, but that is an option I do not have.

    So if you had to pick a task or posture to help set your bench height, what would it be?

    Thanks!

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  9. (I meant hold a chisel in a dado in the comment above)

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  10. Thanks! Planing is the definitive operation for determining bench height, because it can be very tiring on a bench that's too high. It is by far the most physically taxing operation, and can be fairly time consuming. You end up needing to do some kind of planing very frequently, though not always heavy work.

    A lower bench allows you to put your whole upper body mass into it, not just your forearms. But as I mentioned here, that leaves the bench low for almost everything else, so you add something to raise the work from there.

    A lot of chisel work is much lighter, or at least doesn't require your body mass. You can sit on a stool or bench and use a mallet to provide force. The one thing that does require some non-mallet force is chiseling out a groove. Taking a wide stance with one leg ahead and one behind drops you down for that, so you can butt the chisel handle up into your shoulder and again use upper body mass without having to lean over so much.

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  11. Great project, I can't wait to build one for myself. How stable are the I-beams? Is there a stretcher that runs between them in back? I don't want to saw on a wobbly bench.

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  12. Yes, there's a stretcher in the middle of the beams, forming an I out of the I-beams. You can see the dado for it in the one where I'm driving the screws. Once the I-beams are screwed to the underside of the top, and then the base is secure to your bench with clamps or holdfasts, it's absolutely stable. Check out the link above to Joel's blog, you'll see the plan.

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