A good twin screw vise can do many tasks.  When clamped to the edge of a bench top, it can be used as a proper face vise for dovetailing or other joinery.  Sitting free on a bench top, it can restrain an assembly for driving wedges or be a third hand for safely splitting tenons.  In a pinch, it can even take the place of a machinist vise for basic metalworking (although I would recommend vacuuming it off when you’re done, as metal shavings are anathema to woodworking tools).

But a good twin screw vise doesn’t have to cost a fortune.  I mean, it can, if that’s what you’re into (with wooden screws or prefab hardware and whatnot).  But it doesn’t have to.  In fact, all it really takes is about US$13 worth of home center hardware and some off cuts.

That is some straight grain, eh?

There are two typical ways to make a vise screw work without a garter that attaches the movable jaw directly to the screw.  You can affix the screw to the back jaw, and turn a nut to sock down on the moving jaw.  Like the Benchcrafted Moxon Vise.  Or you can affix the nut to the back jaw and use the screw hub to sock down on the moving jaw.  Like the Lake Erie Moxon Vise.  For this, let’s do the latter.  There is a third way, which I’ll cover briefly below.

Start with the front jaw.  Now I am sure there are people who can use a brace and bit and drill a perfectly perpendicular hole.  But I can’t, so I used the drill press.  The screw should be relatively snug in the hole (phrasing?).  This threaded rod is about 3/4″ and a 3/4″ forstner bit was just tight enough.  Inset the holes at least 1 1/2″ from the ends of the front jaw for strength.  Some people elongate their holes to permit clamping irregular work.  I don’t.

Also chamfer the holes.

It’s super important when making a twin screw vise that the holes line up.  So clamp the front jaw to the back jaw and use the same drill bit to transfer the center of the hole into the back jaw.  I should mention that the back jaw is about 4″ longer than the front jaw for some clearance each end when clamping to the bench.  Otherwise, the clamps get in the way of the work.

After you’ve bored the hole in the back jaw, put both jaws back together, insert the threaded rod, tighten up a nut on both sides of the jaws and trace around the nut on the back jaw with a marking knife.  Then chop down to the lines about three fourths of the height of the nut.  Repeat for the other nut and use a small bit of epoxy to affix the nuts to the back jaw.

I do not know if the orientation matters for strength, but the epoxy will help.

Balance is an important part of any twin screw vise.  Even with the narrower front jaw, it’s likely the vise won’t balance itself with the front jaw hanging completely off the bench.  So I typically add an extension to the back jaw flush to the work surface.  It adds weight and stability and is a convenient place to put down your pencil or marking knife when cutting joints.  Glue should be all you need, but maybe add a screw or two through the inner jaw to make sure everything stays put long term.

Some not-as-straight grain.

When the glue dries, you’ll have a functional vise.  There is something called a “rod coupling nut” which is really just an elongated nut.  You could use a couple of these as floating hubs and the vise would work just fine.  It wouldn’t be super comfortable (you’d have to turn the threaded rod by hand) and the nuts would wear into the front jaw over time, but it will hold.  Want proof?

Proof.

You could also affix one of those rod coupling nuts to the end of each threaded rod and also be done.  But I like wooden screw hubs, so let’s do that.  Start with square stock and drill into the end of the hub.  I used the drill press, but you could do this by hand.  Just clamp the work across all faces to prevent splitting.

Drill press vise for safety.

I think it took more time wedging underneath the benchtop to get it perfectly level in all directions than it took for the epoxy to set.  Be careful not to make too much of a mess, but excess epoxy can be used to reinforce the end grain of the hub (that wears against the face grain of the outer jaw).  When the epoxy was set, I drilled through the hub across the grain and pinned through the threaded rod with a 1/8″ steel rod (fixed with superglue).  Probably not necessary, but who knows what that zinc coating will do long term?

If these were raw steel, the epoxy would be more than enough.

Then shape the hubs as you see fit.  I put a small chamfer on each corner of the hub for starts.  I have a feeling it’ll get down to roughly octagonal by the time it’s done.  I don’t like round hubs.

And that’s it.  Clamp it to your workbench and have at some joinery.  Maybe add a coat of penetrating oil finish to all surfaces other than the inside faces of the jaws.  I may glue some leather to the outer jaw to increase grip, but it’s not strictly necessary.

That’s the steel pin through the handle.

If you’ve never made a vise before, this is a good way to figure it out.

I am, at this point, nearing US$100 into the low plywood workbench project, but it feel like it’s pretty much done.  I need to bore a few more holes in the bench top (and make a few more dogs) but that’s more planning than labor.

After undertaking this experiment, I have some thoughts.  But first, now that the vise is done, it’s time to make a little tool chest on this workbench!

Or, whatever.

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Only by working on a low bench, like the plywood roman workbench, can you truly understand what they’re all about.  And after a week or so, I can definitely say there is something to finding the correct height for your body.  I’m just a shade over 5′ 10″ tall and I find 19 1/4″ to be the right height for saw benches.  And of the two low workbenches I’ve built in the past, one was 19 1/4″ and the other was 19 1/2″.  Both are very comfortable heights for me.  I build sitting benches within this range as well.  It’s the height from the ground to the bottom of my kneecap.

Like this one.

But I’ve been working with the plywood Roman workbench propped up on my existing saw benches, which are already 19 1/4″ high.  That means the working height of the plywood Roman workbench is currently over 22″ high.  WAY too high for me to work comfortably.  I’m on my tiptoes most of the time, which is at least a good calf workout.  So let’s make some mini sawhorses out of construction grade 2×4’s to bring the slab to the correct working height.

This is where we are going.

I always start with the math:

First, stand straight up with your feet flat on the floor and measure from the floor to the bottom of your kneecap with a tape measure. That is your overall target height (in my case, 19.25″).  Second, subtract the thickness of the plywood slab (2.875″ for me).  So I need to raise the slab 16.375″ (or 16 3/8″) off the ground.  Let’s round up to 16 1/2″ to make the math easy.

In the United States, construction lumber may be called “two by’s”, but it is really 1 1/2″ thick.  I dug through the stacks at the local Death Star and found two, 10 foot long 2×4’s in Douglas Fir that were relatively straight, relatively clear and relatively dry.  You could, in theory, get everything you need from a couple of eight footers, but why risk it?

Each mini sawhorse consists of six boards, all cut from 2×4’s:

• Two foot boards (20″ long or so)
• One top crossbeam (16″ long or so) – the freer of knots, the better
• One lower stretcher (cut to fit, but around 14″ long)
• Two vertical posts (total height of the sawhorse, minus 1″ [or 15.5″ in my case]) – these should come from the clearest sections of the lumber.  No knots at all, if possible.

Start by preparing the boards.  If your stock is straight and square and out of twist already, give it a quick smoothing pass and proceed to step two.  If not, and you’re feeling like a machinist, plane a reference face and square up a reference edge, then bring the opposite face and opposite edge into parallel.  I only had to take off about 1/16″ of total thickness on each board, so I’m sticking to the round numbers for purposes of this guide.

Face mark, square mark, grain direction.  Every time.

Each post connects to the foot with a 1/2″ through tenon.  For the mortise, bore with a 1/2″ bit and pare to the lines, or chop with a chisel, up to you.  I chopped with a 1/2″ chisel to keep my skills up.  I also prefer to split my tenons, rather than saw down the cheeks.  But it is precarious work to split tenons without a vise.  After everything is fit, shorten each tenon to about 1/8″ less than the thickness of the foot board to give some clearance when it sits flat.

One of two.

With one of the posts firmly seated into its foot, measure up to the total height of the finished sawhorse, minus 1″.  Cut off the post at this line and mark and use it to transfer the mark the other post (while in its mortise) .  This should ensure the two leg assembles are close to or exactly the same height.  Now, assemble each leg assembly with glue.  I drawbored these mortises and tenons too, but it’s not necessary.  Nails or even screws would be just fine to reinforce the joint.

I think this shot was pre-drawboring.

The top beam attaches to the posts with dadoes that are inset from each end of the beam by the same distance the post is inset from the outside of the foot (in my case, 1″).  Determine the depth of the dadoes by subtracting from the overall thickness of the beam the height you need the beam to rise above the leg assemblies to get your final height (in my case, about 1/2″ dado depth).  Do your best to get tight dadoes, but they will be reinforced with dowels after the glue dries.  Err on the side of too narrow, as the construction lumber will compress.

With dadoes seated.

The stretcher connects to the legs with lap joints.  You can use the finished top beam to transfer the distance between the shoulders of the lap joints.  I trimmed the lap joints to be flush with the outside of the posts, but that’s not strictly necessary.  I didn’t get a good picture of the lap joint process, but take a look here.

Glue the top beam onto the posts and seat the stretcher in place while the glue dries.  This will help keep everything square during glue up.  Then glue the stretcher to both the legs and the feet.  After the glue dried, I drove a pair of dowels through the top beam into the posts and couple of nails through the lap joint on the stretcher into the legs.  This should help with any wracking (front to back and side to side).

And then do it all over again.

One is somewhat heavier than the other because they’re made from different 2×4’s.

I’ll be taking a slight detour in the next post to make some more workholding for future projects.

For now, Happy Birthday, America!

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From my experience, a large portion of work holding when using a low workbench is sitting on the work.  But any good workbench for hand tool work needs at a minimum a planing stop for hand planing and a bench hook for sawing.  So let’s add both at the same time through a pair of bench dogs at one end of the newly-squared plywood slab.  Fair warning, the list of tools needed is going to increase from this point on.

This is pretty much all you need for most woodworking.

Let’s begin with locating the dog holes.  In my experience, a single point planing stop will work without re-positioning the wood for boards up to about 5″ wide.  So on this bench, I spaced the dog holes at 5 1/2″ on center, equally spaced from each edge.   4″ from the end seems about right as well, so the dogs can be used as a bench hook in either direction.

I used a brace and bit to bore the holes, but a drill driver works just fine.  Use the bit that is the same size as the dowel you purchased (mine are 3/4″).  Do your best to bore the holes vertically, although if you’re going to err, hopefully err on the side of angled toward you.

Two squares make boring true much easier.

Yes, this is a workbench, but don’t bore all the way through in one shot and break out the underside.  One day, you’ll probably flip the slab over and breakout is unsightly.  Instead, stop when the point of the bit just pokes through, then flip over the slab and finish the hole from the other direction.  That way, you’ll have clean exit holes on each face.  Then, break the edges of the hole with a countersink bit in a drill driver, a chamfer bit or roundover bit in a router, or with some coarse sandpaper.

I prefer chamfer to roundover for dog holes.

Now, let’s make bench dogs.  You should feel free to purchase commercially made metal bench dogs and be done with it.  I like the brass ones from Lee Valley and use them on my main workbench.  But hand made bench dogs work great too.  Start with lengths of dowel that are 2″ longer than your slab is thick.  In my case, 5″.  Now, jam the dowel into the hole you just bored.  I had to use my main workbench because the dowel I purchased was apparently a bit undersized to the hole I bored.

Nice, straight grain.

Orientation of the relief on the bench dog is critical to strength and grip.  Align the growth rings left to right, and mark a pencil line top to bottom that is about 1/4″ from the right side (left side, if you are left-handed).  Now, saw down that line, angled in about 2 degrees, to a cut depth of 1″ or so.  Then crosscut the waste away.  I used my leg vise but you can just clamp the dog to the slab or crosscut while the peg is vertical in the hole.  Be sure to ease the hard edges of the dog with some sandpaper of any medium grit.

That’s literally all there is to it.

If your bench dog is snug in the dog hole but moves with light mallet taps, proceed to the next paragraph.  If the fit is too tight, thin the diameter of the dog a bit with some medium grit sandpaper, checking the fit as you go.  If the dogs fit loosely, like mine were, maybe buy some cheap brass bullet catches for cabinet doors or check out this Paul Sellers how-to on making wire springs for bench dogs (it starts at about the 11 minute mark).  If you use bullet catches, make sure to locate them in a place where they will catch when the dog is both up and down.  You’ll see what I mean.

Add a coat of Boiled Linseed Oil or Tung Oil (whatever you used for the bench top, honestly) and you’re done.

Bullet catches are useful for a bunch of applications, honestly.

Once the oil finish is dry, pop in the dogs and have at some face and edge planing.

One advantage to having two bench dogs instead of a single planing stop is you can crosscut boards using both pegs as a bench hook.  Like so:

Goodbye, knot!

The slab now has all the workholding you’ll need to make two mini saw horses to replace the milk crates or buckets that you’ve been working on to this point.

I just finished up the prototype using just the slab with two bench dogs as my work surface.  I’m pleased enough with the design that I’ll replicate it for the second one.

Basically 1/2 scale to full size saw horses.

But more on that later.

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