I've got that style of clamp.
Be aware that when using any style of corner clamp, the clamping action will roll -especially square tubing....and can set it out of square.
IOW--these corner clamps won't set things square--if you bother to check.

The fastest, most accurate thing I do is use magnetic clamps--not to set squareness, just to hold the parts--then check with squares, measure diagonals/parallels/etc.

I'll only use any corner clamp--now, solely to help fixturing; since it can't be trusted to hold square for a bunch of reasons.

 

Any recomendations? I'm looking at the Bessey WSM-9 clamp. Any cheaper alternatives beside the cheap Chinese knockoffs?

http://ecx.images-amazon.com/images/I/51A4P1G7NTL._AA280_.jpg

Check out Valtra Clamps at www.valtrainc.com Click on "Welding Products" from the home page. They have a lot of really neat clamps, the WAC35D should be comparable to the Bessey model you listed. If I remember correctly, we sell the WAC35D for about $72.00.

 

I'll only use any corner clamp--now, solely to help fixturing; since it can't be trusted to hold square for a bunch of reasons.

Thanks! Ok, I'll bite...... why or how so?

 

I just finished a project, made from 2" and 1" square tubing using 90 degree glue clamps actually designed for woodworking. It is correct that they won't pull the the steel tubing into square, but if you use a framing square, they will help it stay square and lined up while you set the rest of your corners.

 

Thanks! Ok, I'll bite...... why or how so?

1-Geez! I briefly mentioned the 'why' in my post above.
Be aware that when using any style of corner clamp, the clamping action will:

-roll the tubing (round or square)-due to the needed sliding clearance between the moving clamp part and the clamp body

-can distort the tubing, if clamped hard enough, for more distortion.

ALL of the above, become apparent when you check diagonal, parallel, layout dim's, etc.

Repeat: The fastest, most accurate thing I do is use magnets--not to set squareness, just to hold the parts--then check with squares, measure diagonals/parallels/etc.

I'll only use any corner clamp--now, solely to help fixturing; since it can't be trusted to hold square for a bunch of reasons.

The above practices I mention have been in use, in a fab/repair shop, I've owned for 19 years--not a hobby shop. I'm solely interested in tools and procedures that make fitup, faster, easier, more accurate.
'Normal' shop practice is to pull diagonal 'square' within +/- 1/16"...ditto for parallelism
..'Tight' tolerance means +/- 1/32".....ditto for parallelism
(The above tolerances, simply help make things work and fit; and aren't that hard to achieve.)

The corner clamps make fitup harder--not easier.....that's 'why'.

 

magnet fitup example

http://www.weldingweb.com/attachment.php?attachmentid=15159&stc=1&d=1199086587

Above is an example of using magnets in fitup.
In this pic. two of the largest sides are identical; which is often the case. Good fitup begins with accurate cutting and mitering---IOW--the parts are cut to same lengths, etc.
One of the fixture's sliding crossbars is positioned to support the work.
Proceed to fitup one side—the MASTER.
(This pic shows two stacked, I don't have a pic of the MASTER fitup.)
Weak magnets are used to hold the 4 tubes in position, with shims under the single, 1 1/4" dia. round tube. Strong magnets are used for the end stops, as shown.
Check with corner squares, either inside or outside corners, wherever the magnets are not placed, to get things, 'close'.
In most fitups, do not allow for any weld/penetration gapping. Grind bevels, for full pen. welds before the fitup.
Allowing for weld gapping, is a guarantee for distortion and weld pulling.
After the squares show, 'close', then tape measure for length & width dimensional control.

If that looks good, then measure diagonal, and gently tap the parts around,
to 'PULL SQUARE'. It's this diagonal measuring, that insures accuracy.
'Pulling Square' is where they separate the journeymen from the wannabee's!
Normally, in most of my fitups, I like to see +/- 1/16"........SQUARE.
If there's a reason, I can pull square within 1/32" total.

Tubing, angle iron, flats, etc. are not dead true, straight and flat.
PULLING SQUARE, compensates for these normal characteristics
and gives one the best, no-guess accuracy they can hope for.
Simply measuring for height and width, fooling around endlessly with the squares, doesn't produce accuracy, just wastes lots of time.

For this first, MASTER, I tacked on the inside corners—only. Tacking on the outsides
can create some weld 'pulling' and distortion.

The duplicate(s) are quickly and accurately tacked up, via the magnet setup, shown above.
More tacks are added after the sides are fit-up.

 

Dave - Thanks so much for the detailed info. I'm a newbie welder, making a "midlife" course correction and by nature, I'm a sponge for information and your replies were perfect!

It seems that the angle clamps won't be as much help as I originally thought and not be cost effective to purchase. The magnets and a good tape measure are far cheaper and produce better results with a little noodling....

Thanks again!

 

I don't know if the link will work, but I found this in Make magazine

http://www.make-digital.com/make/vo...om/make/vol03/?pg=170&search=angle clamp&per_page=5&results_page=1&doc_id=26301

In case it doesn't work, the author just took a piece of 6" flat iron and attached 2 pieces of angle iron to it at a right angle. I suppose it would even be possible to make an adjustable jig to fit a range of angles...

 

I don't know if the link will work, but I found this in Make magazine

http://www.make-digital.com/make/vo...om/make/vol03/?pg=170&search=angle clamp&per_page=5&results_page=1&doc_id=26301

In case it doesn't work, the author just took a piece of 6" flat iron and attached 2 pieces of angle iron to it at a right angle. I suppose it would even be possible to make an adjustable jig to fit a range of angles...

1-That's a good primer link above on 'how-to', for lots of folks--thank you.

2-The angle clamp fixturing, shown in that link is 'okay--sorta'---but, as I note in my post above--one has to to measurements to the outer edges of 'whatever' they're fitting up, to make sure they're 'pulling square'. Those angle clamps can only get one 'close'.....but not dead-on. Getting within +/- 1/16" diagonal, with parts cut to same length, for most purposes, means no problems--on the assembly's fit, function, or the way it looks. Sometimes it needs to be closer, sometimes not--depending on the part's function.

Fitup is always a balancing act--between measured length, width, parallel, diagonal, perpendicular---leaving the fitup person to determine which characteristics are the most critical ones to hold--to produce a functional assembly.

Using sets of these (angle clamps, vee blocks, etc.)---can and is used in production fixturing. The fixture setup accuracy again is verified by measuring diagonal, length and width--especially diagonal.

 

Bessey clamps are worth there weight in gold.

 

Sighting with the eye is a check for parralellism

 

I could never use those welder's magnets. Our shop is a clean shop yet there is still an incredible amount of grindings everywhere. After 5 minutes, those magnets would be all furry and nothing but a nuisance.

I prefer to use C-clamp visegrips wherever I can...Bessey Clamps are good clamps, but don't over tighten them and realize that it takes nothing more than a single blow with a hammer to disengage them, so don't rely on them with your life.

There are a thousand ways to put square frames together, lets face it, it's not rocket science. I'll agree that measuring diagonal is how to square things, and commonly we like to be within 1/16". I've never heard the term 'pulling square' and tossing it around certainly doesn't make anyone a journeyman.

Like I said there are a thousand good ways to do it...I like to set the overall dimensions, tacking in a manner that allows the frame to hinge at the corners so that it can be adjusted. Check diagonals, determine the difference between the two, add half of it to the smaller dimension and this is the number that you are shooting for.
Put the pony clamp across the longest diagonal and hook your tape on the far corner of the shortest diagonal. Watch you tape and crank up the clamp until you get the number you're looking for. Tack a temporary brace across any two adjacent sides...and then she's not going anywhere. tack up solid and weld...Done deal.

You can measure Diagonals from anywhere...the key is that you remain absolutely consistent in the manner in which you do it. What you do on one side ...repeat the method on the other side.

 

my replies are in blue

I could never use those welder's magnets. Our shop is a clean shop yet there is still an incredible amount of grindings everywhere. After 5 minutes, those magnets would be all furry and nothing but a nuisance.

**The magnets are cleaned with a wisk broom or carefully blown clean with air (wearing a face shield!). Magnets are stored--off the layout area.

I prefer to use C-clamp visegrips wherever I can...Bessey Clamps are good clamps, but don't over tighten them and realize that it takes nothing more than a single blow with a hammer to disengage them, so don't rely on them with your life.

There are a thousand ways to put square frames together, lets face it, it's not rocket science. I'll agree that measuring diagonal is how to square things, and commonly we like to be within 1/16". I've never heard the term 'pulling square' and tossing it around certainly doesn't make anyone a journeyman.

Tinbasher--I've got nothing but respect for the level of work you do. That said--pulling square was a term I got from journeymen--I employed.
IMHO--the journeyman is capable of creating to print, taking into account-all the elements of form, fit, and function.

Like I said there are a thousand good ways to do it...I like to set the overall dimensions, tacking in a manner that allows the frame to hinge at the corners so that it can be adjusted. Check diagonals, determine the difference between the two, add half of it to the smaller dimension and this is the number that you are shooting for.
Put the pony clamp across the longest diagonal and hook your tape on the far corner of the shortest diagonal. Watch you tape and crank up the clamp until you get the number you're looking for. Tack a temporary brace across any two adjacent sides...and then she's not going anywhere. tack up solid and weld...Done deal.

Your's Truly, uses temporaries, tacking--ditto as you do. It all depends on the job. Tinbasher's outlined a thorough way to proceed.

You can measure Diagonals from anywhere...the key is that you remain absolutely consistent in the manner in which you do it. What you do on one side ...repeat the method on the other side.