Hallelujah, finally, I'm always looking forward to your videos Marius

yeah, in fact i was waiting for that part!

Yes - that is also a good idea. Really liked your video, never knew about the lubrication. Maybe also how well the handle is attached to the threaded bar.

Yes, and probably you have a fix for slipping old clamps too - i repaired mine by welding a little dot inside and grinding it down, works as new but if one has no welder the opions are limited: filing the notches deeper in the bar, or file the hole wider and jam a soft metal rod in it (aluminium, brass, copper), put a bit of epoxy in it - what are viable options?

I think it might help to cover the specific way the jaws become immovable since most of MY clamp failures come from the jaw slipping on the bar. As yet I have been unable to recover the clamps that fail because the problem only gets worse .. I don't know how to "repair" the clamp's jaw movement resistance.

Sounds like Screw Lube theory to me. Lube is the magic in the screw.

It's a Schrödinger's Clamp: When a clamp is in a cardboard box, it either clamps or it clamps harder.

What happens when the clamp is in a box then?

42

What sound does one jaw clamping make?

Checkout 'strong boys'. They are a building tool I can't fathom how they work. Here called 'propmates' kzfaq.info/get/bejne/Z5t_oLJlqtScd5c.html

It works as if the bar is a sprag. The hole in the jaw bar is slightly bigger than the CS of the bar. With a turning force on clamping, the jaw bar rocks and the hole closes up.

Russel Brooks as far as I know, (and I may be wrong), as you tighten the clamp the play in the moveable jaw means that it wants to rotate about its end, but the bar through its end prevents this. This means that the diagonally opposite edges of the hole the bar passes though are gripping the bar with proportionally more force as you tighten the thread. This places shear force across the width of the bar. As the jaws are of no more than equal hardness to the bar’s material the bar remains undamaged (in fact the jaws are normally cast from a softer alloy material and far more likely to be damaged). If the hole the bar passes through were a tighter tolerance to the bar, the rotation would need more force to grip the bar and so in fact a tighter fit may result in greater likelihood of the jaws slipping along the bar. Likewise if they are lubricated. Some bars have fine parallel ridges similar to file reel of saw teeth running across their edge providing a more positive point of purchase whilst the initial grip of the jaws is established. Over time as the hole through the jaws wears or is stretched through repeated application of force (a bit like broaching) the ability of the jaws to establish that first purchase becomes reduced to the point where it is unable to do so and the clamp no longer works. If the jaw rotates too far the direction of force the thread exerts it load through no longer opposes the fixed jaw and again efficiency is lost, so filling the hole of a worn jaw square again doesn’t really work. Sorry if the explanation is a bit rambling its typed around getting the kids ready for bed, and as I say I may be wrong anyway

@@petergray6055 That's much clearer than what I was having trouble saying. The sliding jaw gripping the bar MUST HAPPEN BEFORE any significant clamping force can take place otherwise the sliding jaw would just slide on the bar, away from the item to be clamped.

Thanks, these advises are always welcome

That was an "advisory" and he gave "advice" or words of "advice" .

A candle is very handy for situations were a not messy lube is desired. I often use it for door latch bolt, it makes the doors close so smoothly.

No! Matthias W*a*ndel changed his business to LEGO.

+Alfred Neumann Well... it's only because of his tendonitis issues.. unfortunately.

I know. Just kidding.

I just hope Matthias doesn't get a Lego injury!

I by b by BBC

I've glued on white rubber crutch tips to round handles

thats not even true what do you use when you need a lot of force? a big clamp.

There is anti seize that does not change the friction coefficient. Just look up the data sheets.

DIY Dan deep throat make cause sploooging...

@@ajl9491 don't think that was necessary

that's not correct. I just typed out a whole response, but hit the escape key by accident. If you want to hear it let me know

Actually no. The longer arms mean you need to apply more force at the end of the jaws which sit on the bar. Which means more bending for the bar. Which means the angle between the screw and the jaw changes more as you clamp harder. Which increases friction. Thus, you need to turn the handle harder and more, for a bar with similar cross section, when the jaws are longer, to get similar clamping force.

That doesn't matter. But it's the other way around. The shorter the bar, the stiffer it gets.

@@MariusHornberger but if the bar had no bend, it has no "grip". Shorter bars will have less bend. Maybe it's a quadratic function... You want some bend, but not too much. The holding power peaks somewhere between no bend (short), and lots of bend (long).

In meiner Ausbildung hatten wir einmal im Jahr Schraubzwingenpflege. Das war in den 70ern. Da gabs Wolfcraft noch nicht. :-) Was Marius da zeigt, ist nicht neu, nur bei den Bastlern in Vergessenheit geraten. Er macht da wertvolle Arbeit.

Ich bin auch nur drauf gekommen, weil ich (in gezeigter komischen Situation) die Zwingen nicht mehr auf bekommen hab. Dann hab ich mir danach angeschaut warum das so war.

​@@MariusHornberger So was bekommt die Zwinge immer auf: images.ffx.co.uk/tools/RID10348.JPG. Wenn auch vielleicht nicht auf die Art wie man's sich wuenscht (ich mein', kann die Zwinge brechen).

I thought I stay with the basics for now, but all of your ideas are true

What? I would say the first and the last are right, forget the other ideas. Stiffness is not changing the force! The two jaws have got the same lenght, always! So the moment at the bar divided by the length of the jaw is - the same. Please don´t tell something of a "law" if you didn´t understand it. Unless something breaks, hardening the bar or the levers won´t change anything. Not even the stiffness. I thought the subject of the video is trivial, but reading the comments, it seems that there is need for education.

@@moninum Fastener's screw thread is comparable to driving a wedge into a gap. The nominal force is dependend on the angle of the wedge, hence a finer thread.

@@CosmosCraft Exactly, that was your first point :)

Exactly 👍 stiffness/thickness of the bar is the most important factor

you're definitely right! you can see the bars as springs and the bigger bar has a much higher spring stiffness than the smaller one. so with the same bending of the different bars the resulting clamping force wont be the same (Force = spring stiffness * way). But as you already mentioned you have to apply that force by hand and so marius isnt wrong at all...

I beg to differ. Imho the stiffness of the bar doesn't change anything, given the bar doesn't touch the workpiece or yields. The bend of the bar ist just a reaction to the clamping force, not the other way around. With everything except the bars the same, the clamp force would be exactly the same, just one bar would be bend a bit more than the other.

@@terl0th ..." just one bar would be bend a bit more than the other" The more the bar bends, the more the clamping force is reduced..

@@ThumpertTheFascistCottontail Thats a common misconcenption. The bending doesn't reduce the force. Simple test everyone can do at home: If you put a spring on a scale, zero the scale and put a weight on the spring, the scale will show you the same weight, no matter the stiffness of the spring. I know, you will say a scale measures weight, not force. But this is also a common misconception. A scale can only measure the force grenerated by mass and gravitation, it then calculates the weight (which is why a scale shows different values in different parts of the world)

Have you tried a handle like that?..very uncomfortable to use, so not a good design imo. Just a larger diameter round handle would work and be nicer to use

Willie Klassen john doesnt know what hes talking about hes deeply in love with mathias .....

@@ajl9491 yeah, John does a lot wrong!...and i think he and Matthias have fallen out, but John misses him! : )

@@greco2189 i did better than that and made my own clamps! : )

Square handles are hard on the hand. But IME slightly rounded triangular ones are comfortable. By slightly rounded I mean not just rounded edges but also slightly bulging faces. Better grip without pain. Somehow they fit the geometry of your palm.

loopy Head yes on the phalus...

I recently made a mistake with my clamps. I coated the shafts with 'renaissance' wax to stop rust... But they stared slipping... A quick sand with 120 just on the small edges of the bars (where they grip) fixed it... So this might help in your case also? Worth a shot.

Well said Mr. Watney 🤣

MAGA's don't like science too much.

All the scientific proof in the world wouldn't change a MAGAs mind anyway.

I’m old I just turned 38 so forgive me but ... what the hells a MAGA ?

Make America Great Again

No, not at the pitch that these screws are made