Clamps

[Spectric]

Just wondering what peoples views are on the two main types of clamps used on worktops with 20mm holes and what you use.

You have these screw types amongst many other brands

or these lever types from Bessey, Festool and Makita as well as some lesser know brands from the far east. I think most have a 60mm reach but the Bessey comes in many more variants.

 

[ChaiLatte]

How is a 20mm hole workbench made?

Specifically, is the underside of the holes chamfered or relieved?

On all the clamps you show, the tangent point of the radius on the upper surface to the back of the vertical clamp pillar would need to be less than 20mm to work in a square-edged hole.

I have just measured my standard Makita tracksaw (screw, not lever) clamp and on that the measurement is 25mm so that would not work in a 20mm unrelieved hole. The same measurement on a standard Festool tracksaw screw clamp is 20mm.

Hence, it would be wise to confirm that dimension on any prospective purchase or have a plan if it exceeds 20mm.

 

[Spectric]

That is an interesting point, the Microjig clamps are ok as I have used them but not looked at my Makita tracksaw ones.

 

[Sideways]

I have a half dozen of the lower type - ratchet lever.
They are Axminster brand blue or red, modelled after the bessey version.
They work fine in a 20mm dog hole and in a festool track. At half the price of the Festool ones, they were good value.

Personally, I don't have any clamps with the screw mechanism like your top row. I find this screwdriver action isn't as quick as a squeeze clamp and I don't have the grip to crank it up really tight. Smooth wooden handled screw clamps are the worst of the lot.
I do have both Piher and Axminster long clamps with screw handles but all of those include a hinge so the handle can be bent over 90 degrees for extra leverage.

 

[AJB Temple]

I have both types. Mafell and Bessey in my case. The Mafell ones are screw handle and the Bessey are the lever clamp type and I hate them!

I find with the lever clamps that I often can't get them quite as tight as I would like, and sometimes they are difficult to release as well. Unfortunately I have quite a few small Bessey clamps of this type It may just be me being cack handed. Some of the rotary handle versions also have a handle that can be folded over to get more leverage. I have a few like that and it can be useful either where you need to really squeeze or where its a very tight spot.