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Drill Sizes

5375 Views 29 Replies 9 Participants Last post by  chrisb
Back in the days when I used to do custom cabinetry and carpentry, I use to have this chart I kept taped to my drill bits case that had a table of bits sizes listed in their metric, inches, and numbered equivalents as well as tap sizes for the holes. I never laminated the sucker and depended on it for an interpretation of the puzzeling drill numbers and for tap sizes. It disintegrated finally yesterday when I hurriedly took my bit case out of my tool box and is beyond repair.
I can probably find one on line, but I guess the question I'd like to put to the expert machinist on this list is,,, what are the rules for:
1. Determining what size bit to use for tapping a threaded hole

2. What is the logic behind the numerical descriptions of certain smaller screws and bolts such as 00-90 and 00-80 etc... (I mean I think I understand that the lowere the last 2 digits are the larger the bolt or screw, but what is the theory behind it. What do the first 2 digits mean and the last 2 digits mean)

I've always been baffled mostly by the criptic (at least to me) descriptions of bolts and would appreciate a good explanation of them. I understand the differences between a coarse thread and fine thread, and can do metric conversions but those numbers confuse me every time and I believe that's due to the fact that I never learned the theory behind them.
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Thanks guys. No wonder I had/have to rely on a chart. At least now, I understand the 00-XX nomenclature :)
I can see I'm going to have to read this thread over and over again a few times before I really get, but I'm closer now than I ever was :)
Wow, thats a really cool box. Most of the stuff I do is using the 0 size bits. I have a pretty good set of wood drill bits and all I need for the steel bits in 1 sizes and up. I resolved the issue with tap sizes long ago by not buying bolts that I didn't have the correct bit and tap size for. I learned that after snapping a few taps ;)
I use to do remodels and a lot of them were on slab foundations. There are two ways to install a wall, and one of them is to use a hammer drill and sleeve anchor bolts. You can't get very deep on a cut with a regular drill without ruining the bits. I have hammer drill bits that I've used a hundred times, and I still use them when the rare occasion arrives.
You can use the same concrete bits in a regular drill,,,, I had to do that a couple of times when I forgot my hammer drill or lent it out,,, but its slow. You need a small cold chisel and a lot of determination. But it will save your good concrete bits which tend to heat up if you use them incorrectly on a drill.
I know what you mean about having to move the bit around. It could have just been a river rock. I've had to bust some of those suckers up with a combination of hammer drill and cold chisel alternating from one to the other. Re-bar is usually pretty soft here on the west cost, and the grid that its laid out in makes it hard to hit. I've only hit it occasionally, and since its soft here, the bits on chewed right through, although I have to switch the hammer drill over to drill when I encounter it.
Is that just and image of some software you're selling? If so what language is it writen in and what O.S. does it work on?
If it's writen in Java you should be able to port it over to a palm O.S. with a few tweaks. I would love to have that sw on my Palm Treo, sure beats using the calculator all the time. I was thinking of writing the sw myself and installing on my treo, but hey, why reinvent the wheel :)
"But the real shocker was when a user would show me something my program could do that "I" didn't know about! "

Remember this line "Oh, that feature wasn't in the documentation!?"
BTW, if stan wants to open source his code, I'll port it to the palm o.s. for him :)
VS 97 is an IDE, what language did you write it in?
Hum,,, I'm not real good with VB. Can you port it to c++ or javascript?
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