# Modifying record sash clamps



## ColeyS1 (24 May 2017)

I always thought record t bar clamps were the best general purpose clamps money could buy. Over the years I've acquired quite a few.
I was setting the scriber up on the tenoner, but it was proving alot more difficult than it should be. Pushing the joints together by hand, all was well, introducing the sash clamps caused a slight gap on one of the shoulders, not quite half a mm but still frustrating. 
I've known for a while the slidey part of the clamp wasn't square under pressure, just hadn't realised it was quite so much. I've often found I had to leave a clamp on the odd wedged joint, because one shoulder was ever so slightly gappy. The slidey part being out of square, wouldn't help.





That's the worst one, it must be 3mm out of square under pressure !!!!
The threaded end always seemed fine. It's pushing in the middle of the clamp head so even though it's sloppy on the rail, it's always uptight to what ever it's clamping.
The easiest fix would have been to glue a tapered wedge to the offending clamp head, or wedge the head off the rail somehow with a wedge to keep it pushed up tight . Neither of these ideas seemed very good, in terms of durability and ease of use. Ideally replicating the way the threaded end worked, seemed the best solution. It needed something that would put pressure in the middle of the head, but also allow movement of the face of the clamp(to correct the out of square/sloppyness)




These are the clamp heads, centre punched and ready to drill. With the coolant running they drill quite easily.




This was the proto type assembly. I had some 10mm thick steel 50×60mm and tapped a hole right through it to accept an m8 threaded bar. The bar was then welded in position by welding the hole, then grinding flush. The clamp head had a 9.5mm hole which allowed plenty of movement. A couple washers allow the head to pivot easier and the spring washer near the nylon washered nut, just keeps it under a tiny bit of tension. 
It's seemed to work really well so didn't hesitate altering the rest.
















I've given them a quick wipe of machine wax, so hopefully they'll stay fairly clean. I'd say 80% of the stuff I clamp is either 44 or 57mm thick, so this should really help ! Glued up several doors and sashes over the last few days and so far, it seems like a good modification. 
The lighter duty record clamps had the same treatment 




They were no where near as bad as the t bars, but thought it worth doing.

Seems odd that a decent branded clamp could cause issues instead of curing them, but it certainly seems to be the case.
Just for a laugh, I tried a square on some really old record clamps. ....





They really don't make em like they use to, do they !?!?!!!! (100% bang on square) :lol: 
Cheers
Coley


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## AJB Temple (24 May 2017)

Interesting. All mine are old, second hand off the bay. Just checked them. All square or very close indeed. Just so happens I use a pair of big ones to squeeze up 9 off 4" by 4" oak rafters to cut birds beaks in them.


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## ColeyS1 (25 May 2017)

They must have worked to smaller tolerances back in the day. 
I know besseys have always advertised as clamping square, just thought record t bars could take a bit more banging about.

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## Bm101 (25 May 2017)

That's a really neat solution Coley. Nice one. I use 4mm box steel and I have a variety of paramo, old record and rutlands heads. Quality is also in that order with a big drop off for the rutlands ones (they still work mind). I just use slim wooden wedges under either head and it works fine for me but that's just me in my shed, yours is a far better solution obviously, especially in your situation. Kudos mate. 
Thought the steel was rubber at first glance.....which gave me an idea....  I'll keep my eye out for a bit of freebie rubber matting of the right bouncey/hard type at work. Is there a scale for that I wonder? Them engineers electrical mats they have in plantrooms might do. 
I can picture it now.... 
Engineer 1: Dave..... Dave! Does the electrical mat look ..I dunno.... a bit_ smaller_ to you
Engineer 2: Dunno Dave. It does a bit doesn't it? The OD looks the same but the internal characteristics have altered somewhat. It could be a trick of the light? A failure of its its inherent dampening capacities looks statistically more likely in all honesty.
Engineer 1: What. You mean all those regular square holes cut out of it in random places? But Dave, that cant be mice unless they are good at geometry. Or _terrific_ at post conceptual modern art. It's only you and me that come up to the plantroom. Us and the window cleaners and what would they possibly want with a load of square rubber bits?
Engineer 2: It's a mystery.
Engineer 1: You can say that again Dave.


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## ColeyS1 (26 May 2017)

Bm101":11zb6zbx said:


> That's a really neat solution Coley. Nice one. I use 4mm box steel and I have a variety of paramo, old record and rutlands heads. Quality is also in that order with a big drop off for the rutlands ones (they still work mind). I just use slim wooden wedges under either head and it works fine for me but that's just me in my shed, yours is a far better solution obviously, especially in your situation. Kudos mate.
> Thought the steel was rubber at first glance.....which gave me an idea....  I'll keep my eye out for a bit of freebie rubber matting of the right bouncey/hard type at work. Is there a scale for that I wonder? Them engineers electrical mats they have in plantrooms might do.
> I can picture it now....
> Engineer 1: Dave..... Dave! Does the electrical mat look ..I dunno.... a bit_ smaller_ to you
> ...


Ha ha ha, that made me chuckle ! I guess tough rubber would do the same thing. I like your imagination! 
Coley

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## custard (17 Jun 2017)

It's the same problem with Bessey's and pretty much every other cramp out there. A popular solution is a glue block with a "D" shaped profile, then the pressure is exerted right through the centre of the joint no matter how the cramp itself twists or deforms.


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