Festool quick clamps marring work

[Rick Herrick]

Are the green pads on these not suppose to mar up work surfaces?  I have started to use them more, as opposed to my Irwin clamps and I am seeing the marring issue.  I noticed it on the first pic and then backed off the pressure but its still happening.  Am I doing something wrong?  Can't imagine what, but not sure I want to use these anymore on nicer wood.

 

[MikeGE]

I've never seen these marks when I use my clamps.  The sharp edge might be due to the base digging in because the green clamp surface is not square on the surface when you apply the pressure. 

 

[Birdhunter]

It looks like the edge of the pad is digging into the wood. Is the clamp bent so as to put all the pressure onto one edge?

 

[Rick Herrick]

I've never seen these marks when I use my clamps.  The sharp edge might be due to the base digging in because the green clamp surface is not square on the surface when you apply the pressure.

There have been times when I didn't quite have the room to get the full clamp on the piece but not here.

It looks like the edge of the pad is digging into the wood. Is the clamp bent so as to put all the pressure onto one edge?

I don't think so, all 4 of my clamps are fairly new but I will take a look to make sure.  I noticed this for the first time when using the LR32.  I use these clamps to secure the guide rail to the panel in question.  I guess I need to test all 4 of them to make sure they are doing what they should.  I have seen 3D printed items that are 'pads' for these clamps but I never thought I would need them.

 

[Sparktrician]

Rick, the pads on the quick clamps are hard plastic, and as you've seen, they WILL mar wood.  If you're experiencing the issue, I'd suggest that you cut some plywood (or any other scrap wood) pieces to fit between the clamp pads and the workpiece.  I noticed the same thing with the softer woods like cherry.  Slipping in a pad of a harder wood to distribute the clamping pressure did the trick for me.  [smile]

 

[Cheese]

Like Sparky said, the issue is two fold. The combination of the hard plastic pads along with the amount of force that ratchet clamp is able to apply to a very small area.

I’ve had marking issues with hard maple.

 

[ryanjg117]

Number one reason I seldom use the ratchet clamps anymore. The standard clamps (twist knob) have never marred my work, but perhaps that is due to the lesser clamping force that can be achieved.

 

[Bohdan]

Just don't ratchet them as much and they won't clamp as hard.

 

[Cheese]

Ya, I agree with Bohdan, decide when it’s best to use the screw clamps and when it’s necessary to use the extra force of the ratchet clamps...or just back off on the ratchet clamp a titch.

It’s tough, because while the screw clamps can be linear in the application of clamping force, you have literally no knowledge as to the clamping forces with the ratchet clamps because they are not linear and were never designed to be linear.

They were designed for convenience.

 

[rvieceli]

It's still possible to mar the surface clamped with the screw clamps as well. Don't ask how I know.  [scared]

If you are not careful you can get the clamps skewed a little bit and put some uneven pressure on the head even with the screw clamps. In reality the best practice is to use a larger piece of scrap wood underneath the clamp face to keep from dinging the wood on mission critical pieces.

Ron

 

[Rick Herrick]

Thanks all.  The net of this is, pay attention to what you are clamping.  I just never thought about it, but now I will.  I am curious though about those 3D pads.  Wondering if they are any softer but most likely, not..

 

[AlexThePalex]

Any clamp will dig into the work piece if you clamp hard enough. The good old tried method to prevent this is to put an extra piece of wood between the clamp and the workpiece.

 

[Rick Herrick]

Thanks Alex.  I will keep some 6mm ply scraps around just for that purpose.

 

[Sparktrician]

Thanks Alex.  I will keep some 6mm ply scraps around just for that purpose.

Rick, you might want to use 12mm ply to get better force spreading.  [smile]

 

[Northwoodsman]

I can't get mine to stay locked down.  I have taken 2 sets back and finally went with the screws clamps.  I returned the screw clamps earlier this week.  They would grab at first but then as soon as i started sanding something they would just become loose and fall to the ground.  I returned all three sets to the woodworking store where I purchased them and multiple people looked at them, attempted to show me how to use them correctly, and all said "Dang, these are faulty!".

 

[zachjowi]

Powertec makes some nice clamps that have rubber pads.

 

[Rick Herrick]

I can't get mine to stay locked down.  I have taken 2 sets back and finally went with the screws clamps. 

I will admit, it took me a bit to get used to how they work.  To me, it was practice to develop the correct way to get them to work but I still have to use scrap when I am clamping material I don't want marred.

 

[hdv]

I have these and the the equivalent Bessey clamps. Both can mar your workpiece, because the ratcheting mechanism can exert a surprising amount of force. So, advice no 1 is don't overdo it. Some while back I've taken to sticking self-adhesive cork to the clamping plates and that does make a significant difference. The cork does not slip easily, prevents the marring, and does not get in the way (at least not for my uses). Maybe something you can try?

 

[Rick Herrick]

I think I have a couple of old placemats made out of cork.  I will find them and try it.  Thanks.

 

[demographic]

Cut a bit of ply, use it as a pad.
That advice works for almost any clamp, if that mars the work use something else as a pad.