Cutting & drilling small parts

[STAN]

I'm sure this is an easy one. Just about easy enough for me to screw it up.
I need to make 35 pcs .125 x .375 x 3.400 with 4 holes 1" apart centered from end to end and side to side. Holes are .104-.114 dia. threaded 6-32 NC. Material is 4130 N. Starting with 1 pc .125 x 4.00 X 36.00.
Width and length tol +/- .010. The most important thing is centering holes.
Tools available- drillpress, 4x6 bandsaw, bench belt sander, T handled tap tool, micrometer and caliper.

My plan is to cut .375 wide pcs with saw, debur on sander, cut pcs to 3.400 lengths, clamp locating blocks to drill press plate and drill holes. Debur on sander, tap holes by hand. debur on sander.

My main concern is locating holes and correct dill bit and tap size.

Is this a good procedure? Advice on centering holes. Advice on drill and tap size.

I broker metal and mach/fab parts. I usually farm this kind of thing out. This one is small and looks easy so I'm going to do it in my basement.

Thanks

[wierdscience]

I would suggest making one very accurate original to use as a drill guide this way you only need to make one to close tolerence.I would also cut all the pieces and stack them so that you have two adjacent sides to locate from,doing it this way means that you can locate the parts on the same side every time.

[Oso]

Having done just this sort of thing, I have some suggestions:

1) get an x-y table for the drill press

2) use it to make a jig for the parts, can be just a piece of 1/8 steel, with some adjustable stops to hold the parts in position on it
Make the jig as accurate as possible, with holes for your drill size.
Fo handyness, make it oversized, with a longer extension so you can hold it while drilling, and not have to clamp to save your fingers.


3) to assist with #2, get a strip of metal like keystock and file one side to fit in the t-slot of the x-y table for a reference edge. Check it for truth vs the table by cranking it past a rod held in the chuck, using thin paper strips to check distance, since you didn't mention an indicator. (pull out and be sure tension is close. Only need this if you want better accuracy of centering)

4) Drill a hole thru a block of metal about 3/4 thick, sizing to pass the tap closely. Keep it straight and square.
Tap through that hole, it will keep you straight.

5) use plenty of tapping oil, 140 holes by hand is a breakage danger.

[L Webb]

For the best accuracy I would make a drill jig with drill bushings in it.
You plan on cutting the 4130 normalized down the length of the 36" strip? I think I would cut to length first and then to width.
Good luck with your project.
Les