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previous: Matthew Springer No not the kind in poorly maintaine... -- 10/20/2000 6:28 PM

Re: Pot Holes

10/20/2000 9:04 PM
jrem	Re: Pot Holes You get triangular shaped holes because your drill bit isn't set up for sheet metal. You are using the standard rake bit. Go look at those drill bits that are sharpened like a wood bit, i.e., they have a narrow web point in the center, are flat until the edge, and then have a small 'lip' for an edge. This is an old sheet-metal mechanic's trick that Black & Decker patented (jeesh, they'll run a patent on anything, I guess). What happens is that the outside edge breaks through the sheet metal creating a little 'doughnut' that you've just plugged. This is instead of your standard bit that starts in the center and works it's way out, to the point where the drill bit grabs, and spins the chassis all over the place . . . Good luck, let me know if you need any pictures or drawings of what I'm trying to describe. I made mine myself with standard high-speed drill bits and a dressing wheel/grinder. Have the standard sizes, i.e., 5/16", 3/8", 7/16", and 1/2". They work great and leave round holes . . . jrem.

10/20/2000 9:04 PM

jrem

Re: Pot Holes

You get triangular shaped holes because your drill bit isn't set up for sheet metal. You are using the standard rake bit.

Go look at those drill bits that are sharpened like a wood bit, i.e., they have a narrow web point in the center, are flat until the edge, and then have a small 'lip' for an edge. This is an old sheet-metal mechanic's trick that Black & Decker patented (jeesh, they'll run a patent on anything, I guess).

What happens is that the outside edge breaks through the sheet metal creating a little 'doughnut' that you've just plugged. This is instead of your standard bit that starts in the center and works it's way out, to the point where the drill bit grabs, and spins the chassis all over the place . . .

Good luck, let me know if you need any pictures or drawings of what I'm trying to describe. I made mine myself with standard high-speed drill bits and a dressing wheel/grinder. Have the standard sizes, i.e., 5/16", 3/8", 7/16", and 1/2". They work great and leave round holes . . . jrem.