Box Turning Depth Gauge

This box turning depth gauge is made from aluminum angle 3/4 inch on a side. The attached clamp is made from 5/8 inch aluminum square stock that is epoxied to the angle with JB Weld. The block is bored through with a size F drill allowing the 1/4 inch brass rod to slide freely. The movable clamp is made from 1/2 inch or 9/16 inch brass or bronze rod and it is also drilled through with a size F drill. The length of the aluminum angle is about 5 inches, which is adequate for the majority of boxes that are made on the lathe. The brass knob on the brass rod is optional and is fixed with superglue or JB Weld. JB Weld is a metal to metal epoxy and is available in auto parts stores. It is quite cheap in cost but works VERY well.

To use the depth gauge, place the beam on the top of the base of the box and release both clamps so that the rod slides freely. Measure down on the outside of the box, with the brass rod, to the bottom of the box. Make sure that the sliding clamp touches the top of the fixed clamp. Then lock the sliding clamp. Then move brass rod back(up) an amount equal to the desired thickness of the bottom of the box. Lock the fixed clamp. You can use the length of the protruding brass rod to mark a depth drill for drilling a hole in the body of the box to that depth. Or you can just start hollowing and use the gauge to measure how deep you have gone. When the beam just touches the top of the hollowed base, the correct depth has been reached. This depth gauge is sufficiently robust to stand up to testing the depth with the lathe running, although this is probably not a safe procedure. In practice, if the lathe grabs the gauge, it just spins about the brass rod.

This photo shows the box gauge in use. This is a box that "didn't make it". Its just as well; the sides and bottom are way too thick.