I work (as a design engineer) with a weld shop, we make a lot of unique structures for the amusement industry. We often lay out angled parts or cuts on large steel square or rectangular tubing (10-12 inches), where your average sliding T bevel doesn’t reach across. I made them a couple improvised ones from surplus aluminum bar and a Harbor Freight aluminum ruler… but does anyone make something purpose built for this task? Ideally it would have a 16-24" long blade, a long reference edge, and the reference edge needs to be wide enough to get past the radius on the tubing. A protractor scale right on the device would be a bonus.
Our combination square shoud serve your purpose, the tall body on the sqaure makes measuring and layout on tubing with large radiused edges.
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Right, the square is great, but what I’m after is all the other angles. Just like the woodworker’s sliding T bevel but longer, and with a wider reference edge. It wouldn’t need the slide, it could then have a protractor scale etched in the blade.
Ric here. Go to home box stores. They stock a DRYWALL SQUARE. ALUMINUM has a rail to adjust length of blade and can be set to any any angle. Around 25.00 or so. hoe this helps. Ric Frantz
Hi Ric - we have one of those already. Same problem - not a wide enough reference edge to get around the tube radius. May be just the thing for layout on some plates though?
Really I think the right stops on a framing square would be best, but then they have to do trigonometry to get from angles to inches.
I do give them linear measurements from the long point of the tube so most angles they can lay out without needing a protractor.
Here’s another option I’m looking into, from the woodworkers, pricey but looks to have a fairly tall reference edge.
https://www.woodpeck.com/precision-woodworking-protractor.html
Looking at that adjustable drywall square, it would be relatively easy to put on a bigger reference face by simply using some construction adhesives and gluing that leg of the square to a piece of aluminum channel or angle. You’d have to be sure to set things up right, on a quality table that you know is square and all, but I’m very certainly you could get fit that’s be within tolerance.
If you don’t need the scale on that leg, you could even just use the angle/channel to replace the OEM leg. Then you’d just have to scratch in the lines for the angles you need so you’d have the protractor function. More trouble than it’s worth, imo, since I’m quite confident you could get it to work if you just glued it on to the angle/channel to give yourself the reference surface you need.
For the price, you might try out the Temu angle-finder protractor thing. It looks decent enough, though I don’t know how long it’d last in a busy shop. All-metal construction and seems to have decent enough reviews. The reference face looks plenty wide enough to get around the curve on tubing. And for $10, it’s not a great loss if it doesn’t work like you hoped.