Making holes in sheet metal

[BruteForce]

Ok, this is probably a dumb question, but I'm having a problem. I'm trying to cut nice round holes in 16 gauge steel. I centerpunch the hole, and drill a 1/8" pilot hole. So far, so good. Now, I mount a 3/4" bit in my drill press, screw the sheet metal to a block of wood, clamp the wood in the drill press vise, and attempt to drill the hole.

The darn thing shakes and chatters so badly I'm afraid it'll break.

What's the right way to put such large holes in sheet metal?

I have another problem with my drill press. The chuck is on a tapered shaft, and it keeps dropping out. I don't really want to hammer it in, because then it'll probably never come out. What's the right way to get it to stay in?

[AMXguy]

I used a high quality hole saw when I put the hood pins on my Challenger, it cut as smooth as a hot knife through butter. 

[Challenger6pak]

Is your press a varible speed or just an on and off press?

[422STROKER]

Use a Unibit, available at most home centers, or a carbide hole saw.

Tom

[BruteForce]

Is your press a varible speed or just an on and off press?

It's variable speed - adjustable by moving belts around on the pulleys.

[Challenger6pak]

You have a constant one speed press that you can change speeds with but it is still only on or off.  You can get a foot pedal for it. The more pressure you put on the pedal the faster the press will turn.  It works like a cordless drill; more pressure, more speed. You will have more control this way.  That may help your situation.

[71bigblock]

Anything over a half inch, a hole saw is a must.  I'm sure a nice kit isnt too expensive, and would be used for years.   

[72hemi]

I've had great success with step drill bits, and there are step drill bits available for most range of sizes.

[Alaskan_TA]

Greenlee punches cut MUCH cleaner that any hole saw for larger holes like the ones needed for the trunk and floor body plugs.

Barry

[BruteForce]

Thanks for the tips! Looks like I now have a great excuse to go buy more toys (er, tools!).

[ksierens]

For all of the holes in my car I scribed it, then cut it slightly undersized with a hole saw, then used either a file or a rotary file in a die grinder to take it to the final diameter.  I looked at the hole punches at Harbor Freight, but they all make over-sized holes, and couldn't see spending the money on the Green-Lee punches. Also, just using a hole saw seems to make the holes too big.

[mopardave]

a tappered ream bit self centers and is clean, You can see the depth as you go and it can bevell the edge.