Any tricks to getting things square the first time?

[wd40prerunner]

My instructor had me make some tables for other class at my hall today. I thought i knew what i was doing he let me make a few mistakes then he showed me was to get thing square and keep them there through construction.I spent 5 hour on these two tables and I'm still not done with the last one but with the tricks that i learned to day this could have went really smoothly.So if you have any ways or tricks could you please post them no matter what its for. thanks for any help!

[BLUE2KSS]

why dont you post up what you learned? that might help a few people and it is the point of your thread...


I have learned that using a regular carpenters square is not good enough to square the parting tool in the lathe, but the machinist steel square is the drawer below (lol). this was three years ago now.

[6010]

I tack opposite corners so that any draw tends to cancel out. I use a square as I go to make any adjustments. When I think I have it right I use what Pythagoras learned in 6 th century BC. And that is if opposite sides are equal, and the diagonals are equal, then it is square. Pythagoras wasn't a welder but he was pretty good with numbers.

When I cut the metal I try not to make the mistake of the carpenter who said " I have cut it three times and it is still too short ".

[6010]

Another thing I have seen done if you have a lot of them to weld and you can do it on the table is to get one right. Then you can lay it on the table and tack 2 small pieces of angle at each corner and along the sides as a guide. Then you can lay the pieces in this gig, again welding tacks at opposite corners on the diagonal. This will save you some time.

[Dirk]

Use angle plates. You can't really build anything square without them. Depending on what you are building you will always have at least one axis held square. For example if you are building something flat on the table (note: fab tables should always be blanchard ground, or at least some other machined surface) the table will hold one axis square, while the angle block will hold the other. To be efficient at fab work you have to have the tools. Any fabricators tool box should have angle plates, v blocks, and other machinist tools, without them you will get stack up in a hurry.

[William McCormick Jr]

Originally Posted by wd40prerunner

My instructor had me make some tables for other class at my hall today. I thought i knew what i was doing he let me make a few mistakes then he showed me was to get thing square and keep them there through construction.I spent 5 hour on these two tables and I'm still not done with the last one but with the tricks that i learned to day this could have went really smoothly.So if you have any ways or tricks could you please post them no matter what its for. thanks for any help!

There are a lot of things to keep square when you weld up a table. You also have to know your material and which way it is going to shrink most as you weld it. Because if your table is going to be as strong as the material it is made of. You are going to get some serious pulling as you weld it.

I miter my joints at a 45 degree angle. I only cut one face of the angle iron on a 45 degree angle and fill in the outside corner with weld.

I often use Bessemer corner clamps. I use four of them at once. So that after I tack, I just weld all four joints in the same direction. This way all the stress cancels itself out by putting equal force in one direction on all the parts. It either pulls all the sides in a bit. Or it pushes all of them out a bit. After you get it all welded you just take off your clamps and 95 percent of the time it is perfect.

Usually when I weld the legs on, I have a bit of a gap between the leg and the outside corner of the table top, after grinding. If I am using angle iron. Usually I get the most undercut right at the corners. So I actually tack the corner while it is held way off the table top. Then I square up one side one way and tack that outside corner. At this point it is still easy to break off. Then I square it up both ways and make the last tack.

After I get it tacked. I tend to weld towards the corner. Usually I weld inside and out.

If I don't grind the weld and usually today we do not. I just tack the corner, while it raised up on the weld. And then adjust and tack the two sides of the leg, after I set them with a square. Then weld them up the same way if I ground them.

You can also check square if your pieces are fairly close in length by measuring the diagonal of your table top. It should be the same across both diagonals.

You can also use a pipe clamp across the diagonals to adjust the square of your table top. Then just make another pass with TIG over the existing weld, in the direction you want it to shrink. This will hold it square after you take the clamp off.


Sincerely,


William McCormick

[weldbead]

dirk you gave me a chuckle with the blanchard ground fab table. anyone know how to blanchard grind a driveway?

[Dirk]

Originally Posted by weldbead

dirk you gave me a chuckle with the blanchard ground fab table. anyone know how to blanchard grind a driveway?

Sorry, but I get a chuckle out of people that call themselves fabricators until that they get a print that calls for a +/- .030 tolerance on length and a .005 tolerance on perpendicularity and parallelism on a weldment with no postweld machining. If walk into a "fab shop" and their fab tables aren't machined, they're hacking not fabricating.

[evildrome]

Hi Guys,

I have much the same problem. I want to weld up a 2ft square of 2" square pipe as a base for a CNC router project. I plan to mill the thing flat before I use it but I'd like to keep the milling to a minimum. I'm not overly concerned with distortion in the X & Y directions, just the Z. The pre-milled rails will be parallel to each other, not the base (OK, parallel in the Z axis) but it does need to be flat. The milling machine table is about 18 * 36 and is a good reference surface. I also have big 90 deg angle plates and a couple of swivel machinists vices that I could set at 90 deg to each other.

As far as lining it up square is concerned, I think I'm OK with that. Should I make square end joints or mitre joints? And how do I weld those to stop them twisting relative to each other? This has always been my problem in the past. When I've tried to weld tube into a square I always end up with one corner higher than the other.

I will be using a good DC Tig plant.

Cheers,

Wilson.

[Fat Bastard]

I have been building tube frames for 20+ years, I have used every gadget from the magnetic triangles, mill angles, flat stock clamping things in all directions.

About 8 years a go a settled on one method, I use it on rectangular or round anything where I need to attach something perpendicular.

First I go on the assumption that all cut ends have a bias to lean in some direction, I find that bias. I locate the part (place it where it is to be) noting the location of the corner away from the direction of the lean then tack at that corner, using the tack as a hinge I will square in one direction. If done correctly I can then use the two tacks as a single hinge to square for the other direction.


This works great for when you have a wide tolerance, and you don't get skieered at seeing a gap that gets to be weldered up.

I use the same type process for building a cube like tube structure. Only difference is I never tack the inside corner until I have the cube assembled and have crossed measured for square and have it clamped square then I'll start tacking the inside corner on the side with the clamp since that is the long side and needs to shrink.



Are you all cornfused now.

[Donald Branscom]

Even though you may make your cuts on a machine you must check the cuts with hand tools anyway. A square, bevel gage, etc.,.

It is the fit up that will keep it square as well as the order that the tacks are made.
All the clamping won't keep it square if the fit up is not exact.

The welding is the easy part of the welding job. It is the measuring , fit up, CLEANING, and procedure that make the job come out right.

[Donald Branscom]

Originally Posted by Dirk

Sorry, but I get a chuckle out of people that call themselves fabricators until that they get a print that calls for a +/- .030 tolerance on length and a .005 tolerance on perpendicularity and parallelism on a weldment with no postweld machining. If walk into a "fab shop" and their fab tables aren't machined, they're hacking not fabricating.

You mean platens?

[farmersamm]

Now, I don't know if this qualifies as fabrication.

Certainly couldn't put this ol' thing on a machined table, or a granite check surface. Little too big Never seen 'em put ships on a machined table either.

Tacking correctly, and sequencing welds goes a long way to keep everything square. It just flat out doesn't take care of everything. When you apply heat, you will get distortion. Period. Every weld pulls the structure.

Now ya might get real close, but you ain't gonna get it right on the dime. It takes the extra step. You have to heat to shrink the stretched metal. If it gets heat on one side with a weld, it shrinks on the welded side, and stretches on the unwelded side. That's why somethin' bows when ya weld it. So whadya do?

Get out the tweaker.

The pics are of an old project. The first pic is a stiffener that had to be welded between the two arms on a front end loader. Adding this large mass, and welding it to the structure caused the loader arms to pull. No way around it. Now ya gotta get 'em back to square.

Bottom line, don't stress too much about somethin' pullin', just find a way to deal with it using heat. If heat got ya into trouble, it can get ya out.

[Fat Bastard]

Originally Posted by Dirk

Sorry, but I get a chuckle out of people that call themselves fabricators until that they get a print that calls for a +/- .030 tolerance on length and a .005 tolerance on perpendicularity and parallelism on a weldment with no postweld machining. If walk into a "fab shop" and their fab tables aren't machined, they're hacking not fabricating.

Well aren't you just the the man. lol

You really think all "real fabricating" is done to such tolerances? Climb down off that high horse and walk among the people,

I sure loved when I had a "ground flat" table to work from but like the man said its the skills not the tools that make him great. ( )

[tnjind]

Amen, Fb.

[JTMcC]

Originally Posted by Dirk

If walk into a "fab shop" and their fab tables aren't machined, they're hacking not fabricating.

It's a big, broad welding world out there man and YOUR expierience is just a tiny part of it.

I have friends that I've known for many years that personally net over 1/2 a million per year "fabricating" off the back of a truck in the great outdoors, the sun on their backs and the wind in their face, with no fab table in sight, much less a "machined" table. They would be amused at your "hack" comment.

It's rough when you have exhausted every legitimate investment option (to the max allowed) that the irs allows, and have to find creative outlets to "shelter" your "hack" income from the government thugs

JTMcC.

[evildrome]

"If heat got ya into trouble, it can get ya out."

I've seen this before in body shaping forums. Heat shrinking is a "black art" known only to the few. Everyone understands the principle but its the doing of the thing thats the trick.

I expect we could fill a whole forum full of posts on it. I think to learn it I'd have to see someone do it. Thats how I learn everything else. Anyone volunteering to do a You Tube video tutorial?

Cheers,

Wilson.

[William McCormick Jr]

Originally Posted by Donald Branscom

Even though you may make your cuts on a machine you must check the cuts with hand tools anyway. A square, bevel gage, etc.,.

It is the fit up that will keep it square as well as the order that the tacks are made.
All the clamping won't keep it square if the fit up is not exact.

The welding is the easy part of the welding job. It is the measuring , fit up, CLEANING, and procedure that make the job come out right.

http://www.airgas.com/browse/product...&WT.svl=132853


I have been using four or these for over 20 years. They will hold poorly cut pieces square, if you use four of them on a frame at the same time.

You will get a little bowing either in or out, on the lengths depending on which way you weld them. I always weld in the same direction and they all pull the same way, either in or out.

I would not even think about taking on a job without them. This is how to do it if you get a short run of frames to weld.

Here are some knock off's that look pretty good. However I have never used them. They do look good though.

http://cgi.ebay.com/4-Angle-Adjustab...d=p3286.c0.m14

After all the years of using the Bessy clamps I would probably stick with them.

Sincerely,


William McCormick

[hotrodder]

Originally Posted by evildrome

"If heat got ya into trouble, it can get ya out."

I've seen this before in body shaping forums. Heat shrinking is a "black art" known only to the few. Everyone understands the principle but its the doing of the thing thats the trick.

I expect we could fill a whole forum full of posts on it. I think to learn it I'd have to see someone do it. Thats how I learn everything else. Anyone volunteering to do a You Tube video tutorial?

Cheers,

Wilson.

There's already video of flame shrinking on youtube, a very basic snippet with sheetmetal but at least you can get an idea. I would provide a link but it's something i stumbled over when looking at various metal shaping vids. Try searching for metal shrinking

IIRC the video shows the heated spot being quenched with a wet rag which is one of several methods. All depends on the situation- the last time i did any was on a car bonnet (hood) that was fire damaged, only areas that were backed with strengthening ribs were quenched with a wet rag.

The thing that takes some getting used to is that during the heating phase the panel gets a lot worse!

[Capnbondo]

The thing about heat straightening is it's very much experience based IMO. It is trial and error.

It takes quite a bit of practice to know how much heat to apply and where to apply it.

I mean there's a bit of technique/science to it, but I guess what I mean to say is there's not much of a formula where you can say: "well, my 1.5"x1.5"x1/8" square tubing is warped "x" amount, so I'll apply "y" amount of heat at "z"."

It's kindof a "feel" thing.

What I suggest is to heat/quench a little at a time and observe. It's better to do it 2 or 3 times than over-do it and warp it back the other direction. Then you start to chase your tail so to speak.

[hotrodder]

It can approach that level of science (i did post a link to a book excerpt a while ago, will dig it out later as i'm on my out) but yeah, like welding/wheeling/panel beating etc it's one of those things that you're constantly learning- the curve may flatten out some with time but it never gets to be straight

[farmersamm]

I've never done it with anything like bodywork. Usually with pretty heavy stuff.

As long as you put force in the direction you want the metal to go, heat the opposite side to a dull orange(nowhere near melting), and let it cool down while listening for a tick tick like an engine block cooling down, you will have movement in the desired direction. If you don't hear the sound of the contracting metal, you know there wasn't enough force on the part. Sounds goofy, but it's the way I've figured out to make it work pretty predictably.

I usually do it in degrees. I don't try to make the move all at once. I've had the bad experience of going too far.

[Oldtimer]

I have to pretty well agree with Fat Bastard on both his posts. Sums it up pretty good.

How to build things that are square comes with experience. You learn what to tack where and which direction to weld what and in what sequence as you gain experience. After you pull enough of your projects out of square when you weld them up, you kind of figure out what to do to keep everything where it is supposed to be and how to fix it if you mess up.

[A_DAB_will_do]

I'm surprised that I didn't hear anyone specificly mention using a bubble level to fab things up square.

For those of use without granite reference tables or blanchard ground steel table tops, a level works wonders.

Level, square, and plumb each piece of the assembly as you tack them in place. If the first horizontonal member is level, the first vertical member is plumb, and both are square with respect to one another, then all subsequent pieces can be assembled relative to the first. If you've cut everything accurately to the correct lengths, then the resulting work will be right on.

Lots of small tacks are better than a few big ones. Each tack introduces some shrink or distortion, so keep them small. Use lots of tack welds to prevent the finish welds from stretching the tacks.

Keep your welds as small as possible. Big welds make for big distortion. Most people(myself included) massively over do it when it comes to weld size. Bigger may make for stronger joints and better feelings about the work, but it makes for lots of distortion too.

For structures made from angle iron, I usually tack the right angle corner(the bottom of the 'V' in the angle iron), with a spacer create some root opening and room to move the piece around. Then tack one corner, level and/or square the perpendicular direction, and make a third tack weld on the other corner.

[digr]

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Fast and easy way to square frames and uprights.