Sash Clamps for Lightweight Work

For more information on sash clamps, see our beginner site Common Woodworking.

Interested in Good, Lightweight Clamps

DSC_0460 (1) Cabinet making needs are just a little bit different than joinery clamps in that the extra strength needed for joinery is usually best attained with steel clamps. I like alluminium box-type claps because they so minimise the risk of damage when making fine furniture. Screwfix UK has two clamp types I think are worth getting for the shop and Ricardo from Brazil, one of the men in the class, wanted to take clamps back home with him so I picked them up for him and added an additional two types for testing and retrofitting. The results are really great!

DSC_0118 There is something about lightweight clamps I really like. This week I bought two types of two-foot clamps from Screwfix that look similar to the ones I posted on some time back – I wanted to test them out to see whether the good name of Screwfix could be a better National supplier for everyone to buy from. Along with the recommended retrofit I did in the previous blog outlined here, I made an additional refinement that helped too.

DSC_0130 On the alluminium clamp, the same model as the red ones  shown in the blog here, I filed the inside of the leading edges of the clamp shoe, those that parallel the back edge of the clamp. This prevented the shoe from biting on the back of the alluminium bar as is common with alluminium clamps and also allowed  the shoe to move freely. Waxing with furniture wax made the whole thing as slick as can be. More on the second clamp shortly. These clamps cost £8.99 – £12.99 inc tax depending on length. Here is the link for the 2 footers.


  1. A while back when I made the workbench from your online series I purchased several of the blue aluminum clamps from Harbor Freight in the US. I did your retrofit and the clamps have performed very well.

    1. Hi Brandon,
      One difference between the UK suppliers and the US Harbor Freight ones is that the HF ones do break under heavy torqueing down, which in my view is usually unnecessary for this weight of clamp. UK versions seem not to do this. We may have broken one in four years. I will be posting on some steel bar clamps I really like, but that’s from Screwfix, a UK supplier for UK users I am afraid.

  2. Hi Mr. Sellers, I also bought 8 of the Harbor Freight clamps and retrofitted them your way as well. I used furring strips from the Home Depot. I think they’re 7/8″ x 1.5″ x 8ft, and only 0.97 cents each! They only need planing to fit (no sawing). The only problem is most of the strips have huge, brittle knots, and I have to rummage through the pallet looking for useable ones. But they’re in there.

    I like these clamps too. So far no breakage, but I have noticed that the aluminum around the notches tends to yield somewhat easily. The notch looks like it sinks in and the sides of bar bulge out. This happened on 3 of them after my first time using them (on my workbench top lamination). Perhaps I overtightened (the whole glue up did not exactly go as planned -_- ), but I don’t really think I did. It’s hard to gauge. I’m hoping this is won’t be a problem long-term, and would like to ask if you have noticed this issue at all?

    1. I love the alluminium clamps all round. I like the price and the returns policy at Harbor freight. The UK ones definitely hold up better for some reason. They are different to the US ones and the heads do not break in general and respectful use.

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