Woodworking clamps set: opening, count and force
Updated: 22 October 2026
You have two boards on the bench, glue already mixed, and a search page full of 6-inch titles and kilogram claims. A woodworking clamps set is the pack that has to reach the joint, stay there while the glue grabs, and leave the face unmarked. This guide is the order of decisions beside the [clamps set comparison](/hub/hand-tools/clamps-set): opening first, then how many pieces, then the mechanism, with every force figure treated as the listing’s claim. Peter F. used the amazon.co.uk extracts for these twelve packs, not a lab. Prices are the shelf figures captured for this set. A qualifying purchase can earn a commission at no extra cost to you.
You have two boards on the bench, glue already mixed, and a search page full of 6-inch titles and kilogram claims.
You have two boards on the bench, glue already mixed, and a search page full of 6-inch titles and kilogram claims. A woodworking clamps set is the pack that has to reach the joint, stay there while the glue grabs, and leave the face unmarked. This guide is the order of decisions beside the clamps set comparison: opening first, then how many pieces, then the mechanism, with every force figure treated as the listing’s claim. Peter F. used the amazon.co.uk extracts for these twelve packs, not a lab. Prices are the shelf figures captured for this set. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Jaw opening | Pieces | Mechanism | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Irwin Irwin Quick-Grip 300 mm twin pack | 150–300 mm | 2 | One-handed bar | 8.8 | about £14.90 | View offer |
| Best value |  WORKPRO WORKPRO 300 mm F-clamp pair | 300 mm | 2 | Screw F-clamp | 8.7 | about £12.99 | View offer |
| Alternative |  DEKO DEKO 6-piece one-handed bar set | 6 and 12 inch | 6 | One-handed bar | 6.4 | about £25.99 | View offer |
On this page
Opening, throat and the inch on the title
The inch on a bar-clamp title is a nominal length, not a promise that the jaws will open that far on your timber. In ordinary shop speech, 6 inch is about 152 mm and 12 inch is about 305 mm. Read the maximum jaw opening, then a second number if the same jaw can reverse and push. On the DEKO six-piece the 6-inch clamps spread to 11-9/64 inches and the 12-inch clamps to 17-21/64 inches. Those spread figures are not the clamping opening.
Throat depth is how far in from the edge the bar can reach. Only two packs here print it. The Irwin Quick-Grip twin states a 62 mm throat and a jaw from 150 mm to 300 mm. The WORKPRO 305 mm one-handed pair states a 60 mm throat, a 305 mm clamp opening and a spreader opening of 440 mm. The WORKPRO 300 mm screw pair prints a stated size of 100 x 410 mm. That is not labelled as throat depth, so do not file it next to the 60 mm and 62 mm figures.
How many pieces, and mixed sizes
One clamp pins a point. A second clamp stops the work rotating around that point. A pair is a real set for a single joint, and a thin set for a panel or a cabinet. The two-packs here are the Irwin twin, both WORKPRO pairs around 300 mm and the Jorgensen 600 mm parallel pair. If four corners are in the air at once, a two-pack means a second order.
DEKO gives you four 6-inch bars and two 12-inch bars, and no springs. HORUSDY adds two 6-inch springs to that split. Other shops often say four to six clamps for a starter kit. That is their advice, not a count measured on these ASINs. A mixed box matches several lengths at once. A two-pack matches one length, twice. Corner sets are not bar counts. Anylot is eight aluminium squares, and a case is listed for that set rather than for the bar packs.
Force claims, without a lab
Every kilogram and pound figure in this set is the number on the amazon.co.uk listing. None of these packs was squeezed on a shared rig. The spread runs from the WAIZHIUA claim of 11 kg, which does not match a tensile field of 32.86 pounds, up to the Jorgensen claim of up to 1000 kg, also printed as 2200 pounds. Two units on one page are one claim written twice. The WORKPRO screw pair claims about 272 kg and also shows 600 pounds. Irwin claims 63 kg.
A one-handed ratchet is the tool when your other hand is on the wood. A screw F-clamp is the tool when you can line the joint up and then add a heavier turn. In this set that screw is the WORKPRO 300 mm pair, and a UK review says it does not spread. If the goods do not match the description, the Consumer Rights Act 2015 is the route against the retailer. It does not turn 272 kg into a measured force. The heavier-versus-faster choice is on the one-handed clamp versus F-clamp page.
A first pack from this comparison
For a first bench that has to hold shelves and small frames while you work alone, a mixed one-handed box matches the job, with the review count kept in view. HORUSDY has the springs as well as both lengths, on 70 reviews, at £29.99. DEKO is the same length split without springs, on 25 reviews, at £25.99. If 300 mm is enough and you want the largest comfortable sample, the Irwin twin at £14.90 is the light pair with a published throat, and you should discard the 50 g weight field. If you can use both hands, the £12.99 screw pair is the heavier tool in this grid, with no spreader. A 600 mm panel is a different buy, sorted on clamps for woodworking. How the jaws should meet the wood is on how to use bar clamps.
Common questions
How much spare opening should I leave for cauls?
Leave enough gap for the timber plus the pads and a scrap-wood caul on each face. A few extra centimetres is the margin woodworkers usually allow, and it is a rule of thumb, not a figure printed on these packs. A 180 mm glue line will not fit a jaw that stops at 180 mm once the cauls are in place. If the listing only gives an inch nickname, you do not yet know whether that spare exists.
What is throat depth, and which packs publish it?
Throat depth is how far the bar reaches in from the edge of the work. In this comparison the Irwin twin states 62 mm and the WORKPRO 305 mm pair states 60 mm. The other packs do not print a throat. A stated size such as 100 x 410 mm on the WORKPRO screw pair is not the same label, so it should not be quoted as a 100 mm throat.
How many clamps do I need before the first glue-up?
You need at least two, because one clamp lets the work pivot. A pair from this set covers one joint. A panel or a four-corner box wants more, which is why the six-piece and eight-piece boxes exist beside the twins. Other writers suggest four to six clamps as a starter. That is their advice. It is not a test of these ASINs, and a two-pack is still the right count when the job is one joint.
Is a higher kilogram claim a better clamp?
Not on the evidence in this file. The figures run from 11 kg to a claimed 1000 kg, and none of them is a shared lab result. Two units on one page, such as 272 kg and 600 pounds, are the same claim. Choose the opening, the piece count and whether you need one hand or a screw. Use the kilogram line only as what the seller printed.
Do I need a storage case?
Only Anylot states a case, and that set is positioning squares rather than bar clamps. The bar packs mostly leave storage unstated. A case keeps fixings together. It does not add opening, throat or a second clamp. Buy the reach and the count first, and treat a case as a bonus if the listing actually includes one.
Related pages
Sources
Public UK sources from the research digest, last checked in October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file.
- HSE — Safe use of woodworking machinery (ACOP L114) (retrieved October 2026)
- HSE — Morticer (retrieved October 2026)
- BSI — BS EN 847-3:2013, clamping devices for woodworking tools (retrieved October 2026)
- GOV.UK — General Product Safety Regulations 2005 (retrieved October 2026)
- legislation.gov.uk — Consumer Rights Act 2015, section 9 (retrieved October 2026)
- Muddy Faces — Guide to clamps and vices (retrieved October 2026)
- Irwin — Mini one-handed bar clamp (retrieved October 2026)
- Toolstation — Irwin Quick-Grip mini 2-pack (retrieved October 2026)