Mitre clamps

[outofthefire]

I've got a couple of the woodworking type, but I never use them, mostly because they are generally too small. If its a one off I just clamp the pieces to my bench check for square, tack, check again then either adjust or weld it up. If i'm doing more than one I weld some scrap to the bench to make a jig similar to Richards.

 

[Kent]

I've always found the cast Alu ones to be a mile out of square deeming them useless for there intended purpose. Yes as a good fabricator you learn to adjust to such inaccuracies in equipment but then that defeats the object of having them in the first place. I'm sure some are better than others but my experience with the cheaper ones are out of the box and in the skip

If they cast them off square by a mile I should be very surprised. If someone assembled the parts to be welded in them badly I should expect a poor result.
I think too many race to button stuff fully up. Was taught only to weld out fully once everything was tacked secure and double checked

 

[Kent]

I've got a couple of the woodworking type, but I never use them, mostly because they are generally too small. If its a one off I just clamp the pieces to my bench check for square, tack, check again then either adjust or weld it up. If i'm doing more than one I weld some scrap to the bench to make a jig similar to Richards.

Don't tack to the bench at all these days - just way better to build a fixture bench and sort ways of clamping. The 16 mm holes on mine run perfectly square at 100 mm pitch all over

 

[Richard.]

I

If they cast them off square by a mile I should be very surprised. If someone assembled the parts to be welded in them badly I should expect a poor result.
I think too many race to button stuff fully up. Was taught only to weld out fully once everything was tacked secure and double checked

ive owned a good few Kent and put good squares across the flats. Most of the cheaper ones are not sqaure. Fabrication techniques is a different thing

 

[Kent]

I

ive owned a good few Kent and put good squares across the flats. Most of the cheaper ones are not sqaure. Fabrication techniques is a different thing

Honestly can't say but it has to be realy bad if the block isn't square when you consider the way they are made and on what.
I mean so out you can tell with a square over what 5 "? Finding it hard to believe but have to take your word on that

My point is they still will only produce square joints IF proper fabrication techniques are used - they ain't so good as to prevent all pull from Some nut job running a full weld without everything tacked up first all around! In fact I don't even see why people try this - it's asking for trouble

 

[ukracer]

Honestly can't say but it has to be realy bad if the block isn't square when you consider the way they are made and on what.
I mean so out you can tell with a square over what 5 "? Finding it hard to believe but have to take your word on that

My point is they still will only produce square joints IF proper fabrication techniques are used - they ain't so good as to prevent all pull from Some nut job running a full weld without everything tacked up first all around! In fact I don't even see why people try this - it's asking for trouble

I would say because us novices dont understand the forces involved until we see them in the flesh....

 

[Richard.]

I would say the ones I've used are not sqaure. Find it hard to believe............ Well I think I have worked out how to use a square and fabrication teqnique as I say doesn't change that.
I've done enough of it

 

[Kent]

I would say the ones I've used are not sqaure. Find it hard to believe............ Well I think I have worked out how to use a square and fabrication teqnique as I say doesn't change that.
I've done enough of it

Richard. Can only take your word for it, just trying to figure out how they make them out of square - that's if they are not damaged? Human involvement will be minimum, most likely made by high tech casting from molds or computer programs fed to a specialist mill for the process

The sealy ones ( and others) are all cheapo but frankly bang on square but there are lots of ways you can still narf up in use. One of the easiest is having joint contact that is uneven during tightening or something trapped ( bit of swarf, spatter blob etc) but I am sure even the piher ones can suffer that at considerable amounts more

Toggle jig clamps? Most of those are pressed steel rubbish but still do thier job if set up properly

Though like magnets and all the other gizmos we have now - you need to never trust them 100% cheapo or high end. The times I have seen a big square or rectangular frame checked with a so called Qc calibrated square, yet be out on checking diagonals...

 

[Richard.]

Wish I still had one of them to lay a square across and photograph.

 

[Kent]

Wish I still had one of them to lay a square across and photograph.

Yes. It's just confusing me how you found such a thing. Not doubting what you state it's just boiling my fruit to work out how

The cheapo sealy I have are some form of casting process in alloy and the die would have to be out

 

[Jim Davey]

I use the Phier ones.

And they are sturdy as hell, but depending on the weld sequence the part can still spring a little if you aren't careful about your weld sequence or fit up. For example if the cut isn't dead square and the metal you are welding is touching in one point but has a slight gap opening towards the other side even though the two pieces of metal are square relative to eachother the joint can pull. In that case I tend to get two strong tacks on the gap first each end to bridge the gap, I then fully weld the opposite side to the gap I tacked, allowing weld contraction to effectively try to help pull my gap open (which the tacks prevent) then weld both sides and gap last. This gives me the best result.
If the joint is perfect, you can still have issues if you don't tack all four sides before you start fully welding. A cooling, shrinking weld on a heavy wall box can exert tons of force, that's enough to pull a joint out of square if you haven't tacked it first, unless you have multiple clamps on the box at its ends as well.

 

[ukracer]

I use the Phier ones.

View attachment 93172

And they are sturdy as hell, but depending on the weld sequence the part can still spring a little if you aren't careful about your weld sequence or fit up. For example if the cut isn't dead square and the metal you are welding is touching in one point but has a slight gap opening towards the other side even though the two pieces of metal are square relative to eachother the joint can pull. In that case I tend to get two strong tacks on the gap first each end to bridge the gap, I then fully weld the opposite side to the gap I tacked, allowing weld contraction to effectively try to help pull my gap open (which the tacks prevent) then weld both sides and gap last. This gives me the best result.
If the joint is perfect, you can still have issues if you don't tack all four sides before you start fully welding. A cooling, shrinking weld on a heavy wall box can exert tons of force, that's enough to pull a joint out of square if you haven't tacked it first, unless you have multiple clamps on the box at its ends as well.

At 100 quid each they would need to be able to do the welding for me. lol

 

[Jim Davey]

I never said they were cheap. I bought them mainly to rent out and for demos, you can set up a lovely plate weld fillet using a pair of them. It's been really useful to have then in the shop from time to time, but I couldn't justify them for the few days a year I spend actually fabricating though.

 

[God mode restorations]

They sure look nice thoe...what size are they.....

 

[Richard.]

At 100 quid each they would need to be able to do the welding for me. lol

Look up the bessy ones.
£100 for good quality ones ain't bad.

 

[ukracer]

Look up the bessy ones.
£100 for good quality ones ain't bad.

You dont live in the Midlands..... lol

 

[Bill Edwards]

No idea of make but I have a sturdy angle clamp like the one pictured above.

I'm sure it's square and at times (i.e when things will fit in it) very useful and I'm extremely glad to have it.
But no matter how good the clamp if you put metal in with uneven gaps and weld it in the wrong order when you let it go and put a square to the piece you'll be in for a disappointment, metal is springy.
Clamps are a very useful tool but the basics regarding welding order are still vital.

 

[Jim Davey]

I couldn't agree more.

 

[Jim Davey]

They sure look nice thoe...what size are they.....

I think they have a 100mm jaw opening on tbe bigger ones, and about 60-70 on the smaller one.

 

[Arclikeharrypotter]

Think I'm going to sack off any thoughts of mitre clamps, possibly look at building a layout bench. For the cost of 4 clamps at 150 a piece I could make a decent bench.