Thread: bent I bar sash clamp

I have some bent T bar ones . The old Dawn sash clamps . The standard size and some really Heavy duty ones which don’t bend . Never seen I bar ones I don’t think .
Yeah it’s a problem though . Bent ones are a pain and waste time, and can cause problems keeping stuff straight
Getting them back nice and true is possible . I haven’t done it yet. It is something I’ve thought about more than once over the years .
If yours are like my bent ones it’s not a left or right bend if you had the clamp sitting upright on a table . It’s a big hill in the middle over a long distance . Like you say , caused by over tightening .

The best way I think would be in a simple jig to hold the bar upright . And have that in a press. A sturdy Bearing press will do it I’d think . Slide the clamp back and forth where it needs it and press away .

Heating and bending may be asking a lot . The clamps take on a long bend so getting that length up to heat is to long even with a forge . Unless you did a patch and moved along, that would work . A campfire and a bit more time may be better ?

And you could just belt it back out with with a big sledgy. Hold it in a jig or better could be to weld the clamp with the T bar upright on a steel bench over two high points .
I made a heavy duty steel table and being able to weld things to it so they go nowhere is pretty good .

I guess it depends on how bent they are. The bend in the bar will cause the jaws to angle out so not grip the wood square. For a slight bend I would try and gently persuade it back using blocks and G or F clamps at the bench. Big bend may require heat.
Regards
John

As a side, which brands/models are the best to buy on average price, can’t afford the very expensive ones.


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Careful with heating them, if they're hardened as many are, the heating will make them softer if you carry it too far.

Some careful work in a press should straighten them.

I have straightened Dawn sash cramps as detailed above, except there is no need to heat them, just take it slowly in a the press

Originally Posted by Runningman

As a side, which brands/models are the best to buy on average price, can’t afford the very expensive ones.

Tradetools are a running a special at the moment on sash clamps. I've checked them out in store, they're solid units. With the discount they're about the same price as the Bunnings sash clamps, but the Bunnings stuff is inferior at every turn, thinner body, screw action isn't as smooth, the head is nowhere as solid feeling.

Originally Posted by auscab

I have some bent T bar ones . The old Dawn sash clamps . The standard size and some really Heavy duty ones which don’t bend . Never seen I bar ones I don’t think .
Yeah it’s a problem though . Bent ones are a pain and waste time, and can cause problems keeping stuff straight
Getting them back nice and true is possible . I haven’t done it yet. It is something I’ve thought about more than once over the years .
If yours are like my bent ones it’s not a left or right bend if you had the clamp sitting upright on a table . It’s a big hill in the middle over a long distance . Like you say , caused by over tightening .

The best way I think would be in a simple jig to hold the bar upright . And have that in a press. A sturdy Bearing press will do it I’d think . Slide the clamp back and forth where it needs it and press away .

Heating and bending may be asking a lot . The clamps take on a long bend so getting that length up to heat is to long even with a forge . Unless you did a patch and moved along, that would work . A campfire and a bit more time may be better ?

And you could just belt it back out with with a big sledgy. Hold it in a jig or better could be to weld the clamp with the T bar upright on a steel bench over two high points .

I made a heavy duty steel table and being able to weld things to it so they go nowhere is pretty good .

This is how bent they are. this is a 1.3m long unit. in the middle the gap between the bottom of the bar and ground is 20mm. at the head and tail the gap is 10mm. so 10mm over 1300mm.

Some of these clamps I bought for like $20. thinking if I should be bothered with repairing them

5EEDAA85-878A-4D72-83AF-7904C2622990.jpg

Originally Posted by Albert

Some of these clamps I bought for like $20. thinking if I should be bothered with repairing them

5EEDAA85-878A-4D72-83AF-7904C2622990.jpg

Yeah give it a go . You cant go to far wrong . . That's just a flat bar isnt it ? should be easier . Easier to get bent under too much pressure too .
Interesting head on the thing! The way they put a collar on the thread and how its contained .

I have a pretty good working set but like a bit of metal work, so have been dreaming about building a set of clamps to add to what I have . That head design looks like a good one to possibly copy. Casting Iron not being something I'm ever going to do . Its possible to fabricate that.

I keep thinking a good way to make some would be to use some Rectangular Hollow section as the bar . 50 x 20 or 65 x 35 mm ? 75 x 25 ? 2 , 2.5 or 3mm wall thickness.
I suppose if I ever got around to it I would just have to play and see whats best .

I'm wondering how much better a RHS with its two side beams and braced by its Tops and bottoms would be over a solid Bar or Tbar . I reckon its got to be a lot better .

The standard Dawn ones I have are pretty good but they bend under extreme pressure . They and Saxon ones are some of the best second hand ones to buy .

I was at a joinery business Garage sale last week . There was a small wall of clamps for sale . Some standard section size ones in short lengths and some of the Heavy Duty Dawn section size also short lengths . They were $60 each and all sold very early . Must have been 10 or 12 all together.
You dont get a chance to buy them up in decent sets very often . Going to Auctions or sales of businesses closing has got to be the best way of getting good second hand ones.

Rob