Slipping F-clamps

[andrew_2]

This is for all the poor impoverished amateurs like me out there.

I just saw a Wallybois short on Youtube about how to cure slipping f-clamps, where he advises re-filing the serrations on the clamp bar to improve the grip. I think my solution is better, because it turns a knackered F-clamp into an adjustable G-clamp with not much effort or cost and the same clamping power as a mini sash cramp. Long life to all cheap as chips clamps.

If anyone knows a better way to do it, I would love to hear it.

 

[brocher]

This is for all the poor impoverished amateurs like me out there.

I just saw a Wallybois short on Youtube about how to cure slipping f-clamps, where he advises re-filing the serrations on the clamp bar to improve the grip. I think my solution is better, because it turns a knackered F-clamp into an adjustable G-clamp with not much effort or cost and the same clamping power as a mini sash cramp. Long life to all cheap as chips clamps.

If anyone knows a better way to do it, I would love to hear it.

Excellent idea. I have a couple of very similar looking clamps and they have always slipped. I tend to use these clamps as a last resort when I need clamping to be done!

 

[TheUnicorn]

looks good, certainly save a clamp going into the bin, though I'd loose the pin in seconds, maybe put it on a cord attached to the sliding jaw?

 

[SkinnyB]

Best way I found to fix these is to tap for a grub screw on the back of the part that slides up and down. Try to get the grub screw near to the top as this is where the pressure is applied when clapping. When tightening it will cause the grub screw to dig in to the shaft of the clamp and stop it slipping.

1. Remove sliding part
2 Drill 5mm hole in back near top.
3. Tap for 6mm grub screw
4. Use some threadlock on the threads
5. Tighten grub screw all the way.
6. Back grub screw out a little so that the sliding part slides up/down easy.
7. Grub screw will engage shaft when tightening and provide grip.

Ill try to get some pics, have done about 30 f clamps and have never been an issue since.

 

[Sachakins]

This is for all the poor impoverished amateurs like me out there.

I just saw a Wallybois short on Youtube about how to cure slipping f-clamps, where he advises re-filing the serrations on the clamp bar to improve the grip. I think my solution is better, because it turns a knackered F-clamp into an adjustable G-clamp with not much effort or cost and the same clamping power as a mini sash cramp. Long life to all cheap as chips clamps.

If anyone knows a better way to do it, I would love to hear it.

Sometimes slippage is just old crud and glue. I go to mine with a stiff wire brush first, normally solves it.
But I'll bear this in mind before I bin any clamps. Thanks.
Suppose it'll work on quick clamps too?

 

[Louisvn]

I has experienced the same problem after oiling the clamps and sense then it is slipping. Tried to clean off the oil with no success.
Thank you Andrew_2 and SkinnyB.

 

[kinverkid]

Best way I found to fix these is to tap for a grub screw on the back of the part that slides up and down. Try to get the grub screw near to the top as this is where the pressure is applied when clapping. When tightening it will cause the grub screw to dig in to the shaft of the clamp and stop it slipping.

1. Remove sliding part
2 Drill 5mm hole in back near top.
3. Tap for 6mm grub screw
4. Use some threadlock on the threads
5. Tighten grub screw all the way.
6. Back grub screw out a little so that the sliding part slides up/down easy.
7. Grub screw will engage shaft when tightening and provide grip.

Ill try to get some pics, have done about 30 f clamps and have never been an issue since.

I think I get the gist of what you're describing but looking forward to photos because this sounds like a better solution for one of my clamps. I must have 30 odd f-clamps but only one that slips. Just lucky I suppose.

 

[Owd Jockey]

I've done this before on my 'cheapie' Aldi Workzone F- Clamps. Remember to file the serrations with a very slight downward bias.

 

[andrew_2]

Best way I found to fix these is to tap for a grub screw on the back of the part that slides up and down. Try to get the grub screw near to the top as this is where the pressure is applied when clapping. When tightening it will cause the grub screw to dig in to the shaft of the clamp and stop it slipping.

1. Remove sliding part
2 Drill 5mm hole in back near top.
3. Tap for 6mm grub screw
4. Use some threadlock on the threads
5. Tighten grub screw all the way.
6. Back grub screw out a little so that the sliding part slides up/down easy.
7. Grub screw will engage shaft when tightening and provide grip.

Ill try to get some pics, have done about 30 f clamps and have never been an issue since.

That sounds like a neat solution. I'll give it a go when the next one starts to fail. Thanks!

 

[MorrisWoodman12]

I have a Jorgensen E-Z Hold clamp that doesn't hold. It's similar to the Irwin quick clamps. It was new and given to me because 'I'm good at fixing things'. It's a shame I can't see anyway of using this innovative way of fixing it.

 

[XTiffy]

I think Andrew_2 idea is the simplest. The only refinement I would make is to tap those holes and use a cheese head machine screw, drillin/tapping a hole right at the bottom of the shaft to hold the screw. My older sash cramps have a retaining machine screw at the end to stop jaws falling off.

 

[Agent_zed]

I normally find if it's slipping the way to get it to work is to push it up tight to the workpiece and then hold the bar and put my thumb on the sliding part and push, whilst with the other hand starting to screw the clamp. the pressure from my thumb is enough to get it to jam onto the bar and get enough grip. Don't think I've ever had one that wouldn't get enough grip if I did that.

 

[Fergie 307]

I have always used these, I find they can exert more force.
Had orange ones for years, used to be about £40 for ten from Screwfix.
Recently bought some more from them. Exactly the same design but now black. Many of the new ones clamp ok in the first place but then release slightly.
On closer examination the old orange ones have a Matt finish on the plated bar, the new ones very shiny. Quick rub down with a strip of emery cloth going around the stem and the new ones now grip as well as the old.

 

[ChaiLatte]

I have always used these...

If you look at the high quality sealant guns from the likes of Cox, the part that grips and advances the bar is not punched from 3mm plate, it is maybe 8mm brass.

I find the punched pieces can make notches in the bar, which does not help the smooth action. I might try to convert one to brass as an experiment to see if it improves things (the challenge would be removing the nylon end in a way it can be reinstalled).

 

[ChaiLatte]

The only refinement I would make is to tap those holes and use a cheese head machine screw...

The clamping pressure will not do the threads much good. In addition, if the pressure bends the screw, it would be difficult to remove.

Most modern clamps have factory crimped ends to stop the bar falling off. That does make it more difficult to use them as spreaders so the removable end stop is a good idea.

The 5mm version of these would be a really good solution as the balls stop the pin falling out of the hole and the leash would stop it getting lost.

https://www.aliexpress.com/item/1005006161287145.html

 

[Fergie 307]

If you look at the high quality sealant guns from the likes of Cox, the part that grips and advances the bar is not punched from 3mm plate, it is maybe 8mm brass.

I find the punched pieces can make notches in the bar, which does not help the smooth action. I might try to convert one to brass as an experiment to see if it improves things (the challenge would be removing the nylon end in a way it can be reinstalled).

Good point. Although looking at my very well used examples of the clamps there are no notches in the bar, but a little wear evident on the plate.
Just seems to be the case that the plate grips better on a surface with a bit of texture.
The finish on the original ones look as though they might have been grit blasted or similar prior to plating. The new ones are very smooth and shiny by comparison.
I have a blast cabinet so may try that as an experiment on the new ones
Fortunately my workshop is nice and dry so rust from removing the plating is not an issue.

 

[Fergie 307]

As for taking the end off I assume it is just a ball and socket.
Perhaps a piece of metal or even wood between the back of the plastic head and the frame and a firm tap on the curved end of the rod.
Or sometimes this type of joint will pop off if you just twist them at an angle back against the rod.
Might differ on a caulk gun as the end is often fixed so may well not come off intact.

 

[SkinnyB]

As promised some photos.

The grub screw is a little long but I tend to use what I have on hand.
You don't need to adjust it every time you clamp, just initially so it bites the shaft of the clamp enough when the clamp is tightened to prevent slipping but loose enough you can still slide it easily.

I have seen reference to people filing down the grooves on the shaft but if you think about what actually wears its the cast iron part. Every time you clamp it engages the shaft in a different place so wear is most likely to occur on the inside of the cast section causing it to slip.

 

[Sachakins]

As promised some photos.

Neat