? on keeping things square

[Mark Whiddon]

Hey guys,
I have a question concerning keeping shelves squared up with the rest of a bookshelf. I think I probably have it figured out, but maybe I could get a different opinion on how to fix it. My problem is that I can make shelves (either angle or square tubing) and keep the shelf itself square. My problem comes in when I attach more than one shelf to the rack. Here is how I have been going about making it. I would make one shelf, lay the verticle supports down on a flat surface. The shelf is verticle at this point and the verticle supports are laying horizontal on the table. I tack the two V supports, flip it over and add two more V supports. I try to keep the shelf square as I tack it by checking it with a carpenter's sqaure. It seems that the more shelves the more off sqaure it gets. I am sure the heating of the welds is causing some if not most of the movement by warping. I am wondering if my cutting might also be somewhat at fault. I try to cut pretty precise with my bandsaw but I may have a difference of 1/16" sometimes. I know it is plenty small enough to fill in any discrepancies with weld metal, but is that what would be causing the twisting as I assemble the bookshelf? Or is it just the heat warping that is causing it to come out not square? Would it work better if I assemble the V supports to the shelf in a X type manner such as assemble the 2 oclock piece and then the 8 oclock piece, the 10 oclock piece then the 4 oclock piece? I have been doing it by just rotating the bookshelf as if I was going 2,4,8,10. If there is a homemade jig idea I would appreciate any help and I am sorry for the long post.
thanks Mark

[Guest]

If I understand you correctly, you have 4 vertical poles with rectangle shelves in between. The whole thing is a rectangle box shape. I got lost on the 2 o'clock stuff. I will give you basic stuff here.

Take your 4 vertical posts each the exact same lentgh, lay them together ( |||| ) mark on them where you want the shelves, draw your marks with a combination square across each them all in one motion.

Next take two of them clamp them to the table parallel making sure that the ends are on a common line, like simulating the floor. That will be your base point...all measurements come from that point. Now set your first shelf making sure the distance is accurate right on the lines you drew before. Tack that shelf in place perfectly square. Only tack not weld.

Then tack your next shelf. When you tack all your shelves in place, Lay the remaining two vertical posts on top, line up the lines you drew first, and tack them right on the lines. Now that you have it all tacked up, and still clamped to the table, measure cross corner ( X ) this will tell you if it is out of square. ecause it is only tacked, you can make the necessary adjustments easily.

Weld starting on the posts clamped on the table. Don't try to weld the top side yet. Weld from the bottom to the top always going in the same direction. Putting your welds back to back will help. But going in one direction will cause the warpage, if there is any, to be easy to fix. The idea is to make the heat travel down the piece as in a wave. Skipping around will turn it into a pretzel.

Now, this is important, you have now welded one side which has warped horribly most likely. Turn the thing over and weld in the exact same manner as you did the first side. The resulting warpage on that side will pull it straight.

I have seen guys try to fight the warpage after each step of the way, only to make a mess ot it. This works...using warpage to combat warpage is to your advantage.

I hope I have understood your problem correctly, anyway The bottom line in building things that warp, I weld in one direction drawing the stress in the same direction always. It's alot easier to straighten a bow, than it is a snake.

[Steve W]

keeping things square

Mark, I have six of those square clamps like the one's Rock showed on his post about favorite tools. Those things are very handy to me. They work very good on keeping tubing and small plate square and from moving. Also works great on lumber projects too. As soon as I can I'am going to get a few more.

[Mark Whiddon]

Thanks Rocky,
I believe you understood the problem correctly. I hope I understand your solution. Once the spot for the selves are marked, you then tack ALL the selves on one side with the verticle pieces clamped to the table. Then you flip it, clamp it down again and tack the remaining two pieces. Once tacked you then weld from the bottom up(always in the same direction) along your verticle posts. Thanks again Rocky
Mark