Building a Workbench

James Young · April 26, 2011

Let’s face it.  I’m a handyman nub.  I’ve got a reasonably functional brain, and I’m technically minded, but I haven’t done any real woodworking since high school (I did Tech Studies in years 8, 9, and 10, both woodworking and metalworking).  So it’s fair to say I’m pretty bad.

I’ve used the fact I haven’t had a workbench as an excuse for years.  I’ve been using a card table, which isn’t the most stable of things.  Given that I’m wanting to make an AeroQuad, I need a proper workbench, damnit!  Metal would be best, but I can’t really make a metal workbench without space in order to weld (which I’m also terrible at), and without a bench already.  So wood it is.  I can make a wood workbench without already having a workbench!

Hitting the ‘net, I came across this design at Bunnings.  Fantastic!  All I need to assemble that is a drill (check), a 10mm wood boring bit (check), a hand saw (check), a bit of wood to lean on (check), a carpenter’s square (check), two quick-clamps (check) and a hammer (check).  And then a crapload of wood and some coach bolts.  And some polyurethane coating and Aquadhere.

The finished product!

Going straight from the materials list and diagram from the link is a mistake if you’re a nub like me.  For one, I have absolutely no idea what a housed joint is or how to make it (I do now).  In addition, the top planks aren’t available in 290mm width, only 240mm, so this necessitates a few changes.  And since you can’t buy 70x70mm legs any more, I had to settle for 70x35mm legs, and bolt two of them together in order to make a 70x70mm leg.  But the bolted together legs also necessitate a slight design change.

So, there’s a few gotchas to be aware of if you follow that plan.  The final result turned out well and I’m happy with it, but be aware of it if you’re a woodworking fool like me so you wind out with a decent product;

  • Since your base structure will be ~600mm wide, the two 240mm width top planks you get will be insufficient.  Get a 140x45x2400mm top plank to go in the middle.
  • Since you’re now adding a plank in the middle, that plank will have no support beam.  Get an extra 70x45x1800mm under bench support.
  • That under bench support will require a few 90mm coach screws to fix it to the top cross supports.  You can’t use your coach bolts for that.  Get 90mm so you have 45mm penetration on both the under bench support and the top cross support.
  • You probably won’t be able to get untreated pine for the top planks.  Treated is OK, but please wear a dust mask and safety glasses when drilling and doing anything with it until you get that polyurethane coating on.  It’s treated with arsenate.
  • Whenever you’re joining two pieces together, chuck a layer of Aquadhere or other PVA glue in there.  It’ll add strength, hold the pieces together, and also reduce rot.
  • It’s not mentioned, but get M10 galvanised washers for the nuts and coach screws.  They’ll dig into the relatively soft pine otherwise.
  • Since your legs will be made of two 70x35 pieces bolted together, you can’t put a hole straight in the middle to hold the top and bottom cross supports on.  You’ll need to put two in, one through the middle of each of the component pieces.  I’ll attach a photo to demonstrate what I mean.
  • Since you therefore have two bolts going through the wood structure, keep in mind that you can’t have bolts going through each other.  You’ll need to drill carefully to make sure that they don’t intercept somewhere you weren’t expecting.
  • Given that you arent’ going to be housing the cross supports into the legs, the total thickness of leg + cross support will be 115mm - too long for the 120mm coach bolts you’ll be getting.  You have two choices - get longer coach bolts, or do what I did and counter-sink the head of the coach bolt.  In order to do this, use a 22mm wood boring bit and drill in about 5-7mm, then finish off the hole with the 10mm wood boring bit.  That provides enough room for the head of the coach bolt to get in and lets you attach the washer + nut on the other end.
  • For the same reason you’ll want to counter-sink the heads of the coach bolts on the top of the bench by a similar amount.  That’s also to keep the top of the bench flat.
  • When Bunnings cuts off the wood for you (get them to do it, they’ll use a table saw and will be more accurate than nubbins with a hand saw), make sure you measure everything before drilling and cutting anything at all.
  • While I’m harping on about it, measure once, measure twice, measure three times, and measure again.  And then measure it another time.  And then check it again.  Be absolutely, absolutely sure you’re completely happy with where the piece is so you don’t whack a hole in where it’s not supposed to be.  It’s easy to stuff it up when you have little idea what you’re doing, like me.
  • Put an extra coach bolt into the middle of the bench top planks.  Keep in mind that the front and back bench top supports aren’t in the exact middle of the bench top plank before you drill!  The purpose of this is to pull the bench top planks tight against the supports and stabilize everything a bit more.
  • The pine will soak up the polyurethane like a sponge.  I put on two coats everywhere, and three on the top planks (on all sides).  That used up a 1 liter can.
  • If you make sure that you get your 140mm center plank exactly in the middle of the bottom frame, you can use that as a guide to get the front and back planks on much easier.  You may need to flip and rotate your planks to find the flat and good side so they line up nicely.

After all that (it took me a weekend!), you’ll have a workable bench - with a benchtop that’s 945mm high, 2.4 meters long, and 620mm wide.  Cost wasn’t too high, under $150 - of which half was the top planks alone.  It’ll be damned heavy, so you may want to get it near its final home before putting the top on.

I got it pretty square, which I was happy about, but the floor I put it on isn’t entirely square, so I had to slip a 70x70mm bit of untreated pine under one foot to stabilize it, but it’s as steady as a rock.  I’m pretty happy with it.

Detail of leg bolt countersinking and offsets
Detail of added in middle top shelf support

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