What steel for a drilling jig?

[M&J]

I have a small run of parts I want to drill for interchangeability and a drilling jig would enable this.

About 50 holes will be done so something that can have just enough hardness to maintain the run is desired. Is there a steel that can attain just enough hardness using a propane or MAP gas blow torch available?

Suggestions you may have are welcomed.

[jimmontg]

How many holes are in the part to be drilled? Is it 50 holes per part or like 10 parts with 5 holes each? If you're just drilling 2 to 5 holes you can use or make drill bushings out of round stock and torch the bushing.

[M&J]

Two holes but there may be a variation so possibly 4 holes. I'll look into some round stock. Some of the woodworking dowel fixtures would work but those are more $ then I want to spend. The ironic part is none of my local shops have them. I'd talked to one of the shops and he said for some reason they've had a run on the dowel joinery fixtures.

[jimmontg]

Just use some plain steel and drill small pilot holes in the fixture then drill out the pilot hole afterwards. I've made a temporary drill jig with thick aluminum before and drilled out like 40 to 60 parts, but using a .125 drill bit. Steel will hold up for quite a while using a small drill bit. Or just transfer punch it.

[M&J]

I made up a fixture from 6061 for an initial attempt. I'll be giving it a test this week.

[jimmontg]

I might add that I made a transfer punch out of a small round center punch by chucking it up into my drill gun and grinding the tip to 3/16 (.187) for about .200 from the tip and I'd make a transfer punch jig out of one of my spare parts. Works right on the money today as long as I'm accurate with the pilot holes.

[M&J]

Made up a mock up fixture from aluminum and that seemed to be ok. Decided that using a center finding punch will work. This adds an extra step in the process yet would allow me to verify drill location before going at it since some parts may be sized slightly different.

Was going great on making up the second jig and the final part was to drill the hole for the punch. I didn't see the drill deflect while in the vise and it somehow drifted .02" off. Arrgh!!! I was amazed at how simple this was yet it took 3 hours to build up. I don't get where the time flies in situations like this. This contains 4 holes, 2 tapped, cutting the alu out then a mark around the whole fixture to indicate center...3 hours!!

Will get to make up the third since the second got botched. The more I make the faster I get but this is crazy. The first one took 10 hours including the design phase. <doh> LOL. Definitely not speedy.

[jimmontg]

I did it for so many years it is second nature to me. If the part's sizes change then a transfer punch is it unless you have a reference corner that is always the same. Then you could set up some stops.