Tack welds, Scribing & 90 degree angles

Here is a video that I created as I started to assemble the legs of a table. In the demo, I'm using a set of magnets to hold together the different pieces to ensure that the two pieces are positioned are at 90 degrees.

Here is the link to the video.

Tack Welds

To secure the two pieces together, I'll use a tack weld to ensure that the two pieces are secure before I finish them off with a longer weld across the two seams of the metal. The tack welds are used to ensure that I measured correctly and that the angles are setup correctly before "really" attaching the two pieces together with the longer welds. If I screwed up my tack welds, it's easy to fix.

But if I don't use a tack weld and go right into a longer weld, it will require a lot more work to fix such as using the angle-grinder to cut off the weld, more sanding to clean up any spatter and genuine frustration that I have to start over from scratch.

Scribing

I overlooked the concept of scribing when I first got started in metal working. Scribing is the art of measuring and then cutting the metal to your expected lengths. While the video doesn't show me scribing anything, I never would have been able to get the lengths to the right size without it.

I like to use both a Sharpie marker to identify the lengths (and pieces) that I'm working with and a scribe tool such as this:

The scribing is important because it's easy to cut the pieces the wrong size and that is never a fun exercise to repeat something that you should do once.

90 degree angles

Welding two pieces together at 90 degree angles and have them line up perfectly sounds really easy but it's actually more complex than you think. Depending on whether you have cold-rolled or hot-rolled steel, the steel may or may not be perfectly uniform. I took this for granted when I was trying to figure out the differences and most often two pieces of steel are never exactly the same.

Welding magnets, like the one below really helps the two pieces of steel stay where you want them to and holds them together while you do the tack welds. I can't recommend these magnets enough and I'd recommend that you use two to ensure that you have a tight grip on the steel.

I hope you've enjoyed the video.