‘Frog-Leg’ Indicator Holder
D’oh! I forgot to buy an indicator holder when I did my last mass tool purchase. Rather than trying to track down a decent, cheap one in town (not likely here in NM) or order one and wait for a week, I built one. After talking with Machinist Mike, a ‘frog-leg’ type indicator holder would probably be the simplest and most useful, since it can articulate into just about any position. The shown design is made for a dial indicator, but another end ‘leg’ can be made to attach anything else, like a test indicator.
For material, all you need is 3/8″ aluminum round, which you can find at any hardware store. For screws, you need two 10-32, 0.5″ socket head cap screws and a 1/4-28, 0.5″ button head cap screw. I used a button head for the dial indicator mount, since it uses the same hex wrench as the 10-32. The threading placement may seem funky, but I did it so that all the bolts are facing the same direction when assembled.
Also, the milling process is designed to be easy. After cutting the round stock to length, each leg can be machined in one operation: clamp it high in the vice with a 5/8″ parallel, face the top features with an end mill, and drill the holes. Since you are measuring from the spindle to the indicator, the indicator holder doesn’t have be precise, but, by facing and drilling all of the mating faces of the parts in one step, you can ensure the movement of the legs are in-plane with the spindle axis.
Lastly, if the root ‘leg’ doesn’t fit into the 3/8″ end mill tool holder, just use some fine grit sandpaper to lightly sand down to spec.