Drilling metal CP

[Brad Lee]

I was going to mess around with a metal CP and am looking for some tips on drilling etc. I've got a good 1-1/8"drill bit that I use on wood no problem. Can I use the same for metal or is there a different type I should be looking for.

The metal is actually off an old PC case, back from the days when everything was steel. It's 1/16"(is 1/8" what most of the real metal CPs use?) and each side of the case is 24"x15". Basically I dremel'd right along the crease between top&side, it's one of those wraparound U-shaped cases, and it is the perfect size.

I drilled some holes in a metal plate for my system buttons, that was 1/2" holes, and they all are just a hair off center from the bit wandering and depending on where it actually bit in to the metal. I realize a drill press is the preferred way to get them precisely positioned, but without one, what options do I have?

My 1-1/8 bit has a pilot bit that's about 1/4"    
I do have a center punch so getting the initial holes lined up shouldnt be a problem if i start with the very smallest bit and work up till I match the pilot bit

Any other tips for working with a metal CP?




(This isnt a definite, I just came across the case and thought I'd give it a shot)

[eightbit]

You could use a metal hole saw bit, like what they use for doorknob holes. If you center punch the hole before starting you shouldn't have any wandering.

[Brad Lee]

Right, that's the type of bit that Ive got. I think I'll start with punching the centers then start with a little baby bit, then the next size, then the next until  I get to where I've got holes the size of the center bit(at the bottom fo your pic), replace the center bit with a smooth steel rod so it doesnt dig into the panel anymore, and try to keep it straight up&down when the 1-1/8 bit start grabbing

[Elkor]

PC case metal isn't very thick you shouldn't have a problem using regular-ol-holesaws.  Use lots of oil (3-in-1 is good enough for your purposes) and go slow.

for a center punch just use a nail set.  This is what I used to center punch my metal panel and that was 16ga steel

The only problem I see is strength.  
that metal isnt very strong in sheets, it's the shape of the case that lends to it's stability.

If you want to go this way, try attaching angle-aluminum to the underside in convnient locations to provide ribs for extra support.

good luck

-C

[eightbit]

Right, that's the type of bit that Ive got. I think I'll start with punching the centers then start with a little baby bit, then the next size, then the next until  I get to where I've got holes the size of the center bit(at the bottom fo your pic), replace the center bit with a smooth steel rod so it doesnt dig into the panel anymore, and try to keep it straight up&down when the 1-1/8 bit start grabbing

There is no advantage to drilling multiple holes, except for center punching or drilling the first hole with a normal bit. You need to drill the hole the size you want it the first time with these types of bits. For the secound hole there would be no center bit to guide and hold the saw while it was trying to start the cut. Try it on scrap first, you'll see what I mean.

[Brad Lee]

I tried it at lunch time with mixed results

Taped down a template for the center holes, punched the center. Drilled one with a 1/4" bit, came out just fine. Drilled the other with about 3 or 4 increasing sized bits, came out fine. They both were still right on with the template so that's a good thing for keeping em lined up.

When I went at it with the hole saw however it didn't get any "bite" into the metal and basically just polished a 1-1/8" circle around the center hole. I will be picking up some oil, and I know to drill slow through metal(learned it the hard way before)  Geuss I'll just keep at it and it'll poke thru eventually

[eightbit]

If your using a metal hole saw you shouldn't be having a problem.

[spidermonkey]

Also when using hole saws if you have access to a drill press this helps out ALOT ! The combination of the drill press's even steady pressure and plenty of cutting oil (any oil for that matter) = a clean quick breakthrough.  A friend,neighbor,reletive ? somebody's gotta have one you can use for an hour or two

[NIVO]

if you happen to know a local machine shop, they may be able to precision punch them as well. My metal panels were made by my dad and had access to a stamping press. They are flawless and perfectly sized. Just another option you may wanna investigate. Good Luck.