Building a power tool workbench

These days, bench-mounted power tools like grinders and sanders are incredibly cheap. That’s great – but where do you mount them? Ironically, while stands and supports are available for this type of tool, the cost of the stand is often as high as that of the power tool iteself! With that in mind, we decided to build a workbench that would suit bench-mounted power tools – and also hand-tools (like metal shears) as well. 

Note that to build a similar bench you’ll need access to a welder, angle grinder and (preferably) a friction cut-off saw.

Approaches

There are many approaches that can be taken to building a bench. Here at AutoSpeed we’ve previously covered two different self-constructed designs:

Building A Work Bench– a good general purpose bench with a welded steel frame and timber top.

A New Home Workshop Part 9 – a long, wall-mounted timber bench that doesn’t require welding.

The workbench described in this story is extremely strong and yet costs very little. It’s also long and narrow in shape to better suit its use as a tool support rather than a working surface. Its design uses a steel frame and timber top.

Starting points

The first point to consider when designing a steel-frame work bench is to understand the vast length of steel that’s needed. The bench constructed in this story used something like 16 linear metres of steel! Pay even ten bucks a metre for the material and the frame alone has cost you $160…

The trick is to fine steel that no-one wants – and one answer is pallet racking. The beams used in pallet racking are available second-hand very cheaply – that’s especially the case if they comprise odd collections of different cross-sectional sizes and lengths.

The pallet racking beams used here were left over after I bought a heap of second-hand beams for racking in my shed. The lot of 50 beams cost AUD$200, and I used about 36 of these in the shed racking. Of the 14 remaining beams, I used 11 to build the bench shown in this story. Do the sums and that means the steel for the bench cost just AUD$44.

So before embarking on a steel-framed workbench build, find a source of cheap steel.

This being the fourth workbench I have made over 25 years (with, incidentally, all still in operation), I think the best top for a workbench is thick timber with a thin layer of Masonite (compressed high density fibreboard) placed on top. 

Taking this approach gives the following  advantages:

·       A very strong surface (i.e. plonk a gearbox or engine block on it and it won’t blink)

·       A ‘dead’ surface that will absorb the blows of something being hammered on it without springing back

·       Strong mounting surface for vices, power tools, etc

·       Easily cleaned and resilient surface

Despite the fact that the bench covered in this story is not going to be hammered on or carry an engine block, I chose the same timber + Masonite approach.

The cheapest way of finding thick timber is to look to a salvage yard – or better still, a building demolition site. Roof rafters or flooring supports from older houses are thick, strong – and often hardwood.

In my case, I had a bunch of timber left over from a shed demolition – and also some hardwood I’d previously bought straight from a timber mill. I’d guess that sourcing the timber again would cost me about $40.

When considering designs, in addition to the steel and timber, other ideas to keep in mind are:

-        Use of a sufficiently stiff or braced frame to resist ‘lozenging’

-        The placement of a strong shelf as low as possible under the bench to allow the storage of heavy items – this is very effective in stabilising the bench. Or…

-        …alternatively, the bench can be bolted to the floor.

Building

The first step was to cut the pallet racking beams to size. I used a friction cut-off saw to do this. It could also have been done with a hacksaw (a nightmare) or a cutting disc in an angle grinder. I took the friction saw outside so the huge amount of generated swarf didn’t end up all over the floor of my workshop.

The beams that would form the top of the frame were then arranged on the workshop floor and tacked into place. Note the piece of particle board (arrowed) being used as a ‘square’. It’s very important that everything is square – both in plan view and elevation. Once tacked into position and checked for squareness, the beams could be welded together.

Assembling the rest of the bench is just a case of cutting beams to size, tacking them in place, checking squareness, and then completing the welds. Note the large number of supports that have been used for the lower shelf – on this shelf will be placed heavy objects to stabilise the bench. The additional supports will stop the shelf surface (eg chipboard or Masonite) from sagging under this load.

Welds on surfaces on which the bench top and shelf were to be placed were later ground-back with an angle grinder.

After the frame is completed, give it a coat of paint. To do a ‘proper’ job you should use a metal primer and an anti-rust final coating, however the bill for these paints can blow the cost of the  project out of the water! An alternative which is still fine if the bench is not out in the weather is to use a general purpose, self-priming exterior paint.

Note that if the pallet racking beams are powder-coated (rather than painted), the surface should be heavily scuffed with sandpaper to allow the paint to key into the surface. 

The next step is to mount the timber top. A few different approaches can be taken. Simplest is to use building adhesive to glue the pieces of timber to the metal frame. This can work very well - however, if the bench is to going to cop a lot of hammering or pulling, it’s better to drill countersunk holes and use bolts or self-tapping screws to firmly attach the timber planks to the frame. Place adhesive between the planks so the top becomes a homogenous mass.

If the planks form an uneven top surface, you can run an electric plane or sander over the them. If you don’t have either of those, you can use a hand plane or, as a last resort, a hand saw used at an angle of about 5 degrees - and so ‘rasping’ the surface rather than cutting it.

With the timber flat, place a layer of 5mm Masonite over the top. The Masonite works very well - it is replaceable, quite hard (unlike plywood, it can be hammered without easily denting) and gives a smooth top surface. The edges of the bench-top can also be trimmed with Masonite or simply painted in the same colour as the frame. Attach the Masonite with small brads punched beneath the surface, or use flush head screws – either approach makes it easy to replace the Masonite when the top layer wears out.

You can then oil the bench top - I just use any new unwanted engine oil I have around place. (Don’t try used oil – it may well have nasties in it.)  The oil is applied with a brush, left for 15 minutes to sink in, then any surplus is wiped off with a cloth. The resulting surface is dry, doesn’t show oil stains(!), and can be easily touched-up should it be scratched.

The lower shelf surface can then be placed into position. Any composite board can be used – because it is well supported, even relatively thin material won’t unduly droop. The board can be glued and/or screwed into place. I used the coated particle board from flat-pack bookshelves that had not survived a house move.

Conclusion

The bench shown here is weighty and strong. With periodic replacement of the Masonite top layer, it will last a lifetime.

How they’re made Pallet racking beams are made with one of two construction approaches. Strong beams, of the type used for most of the bench construction, comprise two nested and overlapping sections. The two parts of the beam are held together only by the welded end brackets. This has two important implications: -        When the end brackets are cut off so that the beams can be used in a new project, nothing holds the two parts of the beam together and so they easily come apart -        If the beams have been stored outside, water can easily penetrate the long seams between the two pieces, allowing rust to form inside the beams. If the two-part beam is being used in part of the bench where its end is completely welded to another piece, the two beams parts will again be held together. However, if one end of the two-part beam is not being connected to anything (for example, it is a bench leg), then a short length of welding bead should be run along the seam to hold the nested sections together. Lighter beams use this different type of construction where no special precautions need to be taken in their use.

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