need to drill some 7/8x.188 tubing so i can tap the ends for 5/8 heims... how would you do it? i have a nice drill press with a table with a 1" center hole and a drill press vice, some clamps etc... just wondering what input you guys can lend. thanks.
We used to fabricate gas filters for natural gas. They used several 2" pipes with holes drilled every few inches to route the gas thru the filters. We had a piece of square tubing drilled with holes that the 2" pipe would be placed into. Some set screws to hold it in place, then drill away thru the existing holes in the square tubing.
I think he's wanting to open up the inner diameter. I'd do it in a lathe, if you know someone who has one. But failing that Id use a v-block and clamp the pipe to that, then g clamp the v-block to the machined table on your drill press with the tube poking through the hole in it. once you've centred the drill over it you'll only have to take the pipe out and put the next one in. It will stay centred provided you can lock your table. Be carfull though, if that drill grabs you're likely to spin the whole thing.
.188 =3/16 wall so 7/8 has inside diameter of approx 1/2 drill hole 17/32 for 5/8x11 NC or 37/64 for 5/8 NF
Use the lathe!! It's the ONLY way to get it centered.Any small shop will run them for a few bucks and it is worth it to keep from screwing up some good tubing.
If you want to do it right, take it to a machine shop and pay the man his money. If you chose the right machinist, it wont be a big bill.
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