Another way to skin a cat


 
Yes, you can put them in a corded or battery operated drill. First you would want to use a centering punch to punch a spot for the bit to start in on the bolt. Then drill down with the centering bit until you get a defined hole started. Then switch to regular (quality) drill bits. The centering bits allow you to get the hole started by making it easier to prevent the bit from walking. You don't have to worry about snapping the bit from exerting a little side force when starting the hole.
 
Roy-Parallax said:
How does one use those? Do they go in a drill?
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Yes. I used them like drill bits with a cordless drill. Worked really well. I can't remember now but I think after using these I went with regular bits to widen the hole until the bolt fit. I have been buying the Harbor fright titanium 1/8" bits with the hex shank and they have been working great. I would say just as good as the cobalt bits I was buying.
 
Some really bad reviews on that item but, that aside, I'm still not quite getting what they're for. Are these designed for drilling into metal? They don't look like they could be easily sharpened and, if they could, there's not much space to sharpen before one would run out of bit.

When I was drilling through stainless, I just kept resharpening. Destroyed one bit completely, took 80 to 90 percent of the life from another and several others lost maybe 10% or less. But drill bits are cheap, particularly if one picks them up at yard sales. I could imagine that drilling into the box might be a lot tougher than stainless. I'm brand new to all of this, just figuring it out as I go. Feel free to set fill me in on the details I'm missing.
 
The centering bits at Harbor Freight actually work very well. I was actually able to free hand drill a centered hole to get a lock pin installed on the axle of my little Honda walk behind mower. Used my 12v Bosch drill and center bit (no punch). Just free handed. Stayed right on the nose. Once I got it started well, switched to a small regular cobalt bit from HF, and finished it. Then used a larger centering bit to cut a chamfer to make cotter pins easier to install. They're cheap enough to simply throw away when they're toast as well. They bite so well you don't even need to center punch.
 
GOod to know Larry. I have a really tough time paying for high end drill bits. I have a set with assorted bits, that started with several of each size. Some of the sizes are empty now, but I got a heck of a lot of use out of those bits. It probably has 75 bits total and probably cost what set of good bits with only one per size. I have used some pretty expensive bits and wound up trashing them in one use. The cheap ones (I think Tool Shop) is the brand just go in the trash and I grab a new one.
I didn't know that HF had the centering bits either. Good to know that too but I have quite a few of the perfect size for the bolts on grills.
 
Roy-Parallax said:
Some really bad reviews on that item but, that aside, I'm still not quite getting what they're for. Are these designed for drilling into metal? They don't look like they could be easily sharpened and, if they could, there's not much space to sharpen before one would run out of bit.

When I was drilling through stainless, I just kept resharpening. Destroyed one bit completely, took 80 to 90 percent of the life from another and several others lost maybe 10% or less. But drill bits are cheap, particularly if one picks them up at yard sales. I could imagine that drilling into the box might be a lot tougher than stainless. I'm brand new to all of this, just figuring it out as I go. Feel free to set fill me in on the details I'm missing.
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Their primary purpose, and the reason they are known as a "center drill", is for drilling a 60deg tapered hole in material that will then be supported by either a live or dead center in a lathe tailstock.

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LOL, I actually understood that one. I worked in a machine shop on metal lathes for a year before I joined the Army. I don't recall the center bits, but then, that was nearly 40 years ago.
 
Bruce said:
LOL, I actually understood that one. I worked in a machine shop on metal lathes for a year before I joined the Army. I don't recall the center bits, but then, that was nearly 40 years ago.
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I did too. But they work GREAT for making a pilot hole or doing weird things like putting a hole on a piece of 3/8" round steel all while hand drilling. It was my retired tool and die maker buddy who showed me the many other uses you can do. So now I use the snot out of them
 
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