When doing layout work it's often handy to be able to use one of your steel scales like a calibrated T-square. I made this device to convert either of two of my most-used scales into layout squares.
This photo shows the device with my 6" scale inserted. The extra hole near the hold-down thumbscrew allows it to be moved to accept my wider 12" scale.
This photo shows the hold-down rail and the thumbscrew with its tapered brass washer that forces the scale against the rail when the thumbscrew is tightened.
Although I have a good combination square, I find that I use this a lot more in layout work because the short 6" scale doesn't get in the way as much on small workpieces.
