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Drill Sizes

5354 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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Posted By rkapuaala on 11/05/2008 9:14 AM
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
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Porting the software to a handheld devices would be fantastic. Like others...I don't keep the computer handy in my shop...nor outside. But...if Handy Converter were to run on the mobile operating systems you find in cell phones....I'd download it in a heartbeat.
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Stan: Yep, I have the feature, but even though I have used the program many times, I don't remember EVER seeing it before!

I was a programmer and features that I have built-in to the original version of a program would often solicit the comment from long time users of, "I didn't know it could do that! When did you add it?"

But the real shocker was when a user would show me something my program could do that "I" didn't know about!

The problem with porting any program to a different platform is the need to have said platform in hand to do the debug on. I bet Stan would be happy to attempt to port it to another OS/Hardware if someone were to buy him the necessary platform to see how to do so!
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"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 :)
Sorry - not Java. I was using good old Visual Studio 97 when I wrote the first version, so I've just continued using it. I've considered porting it to .NET, but the benefits seem to be lacking.

BTW, the program has a nice undocumented feature or two (actually documented with tool tips), such as - you may enter fractions in most of the fields (example: you can enter either 12.75 or 12 3/4).

I wrote a German language version too, and it also has undocumented features. It allows you to use either the comma or period for the decimal point. Example: you can enter either 12,75 or 12.75. It's always been hard for me to avoid including "goodies". The problem is you never know what's going to turn out to benefit the user...
VS 97 is an IDE, what language did you write it in?
Posted By rkapuaala on 11/05/2008 5:53 PM
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?
Posted By rkapuaala on 11/05/2008 10:50 PM
Hum,,, I'm not real good with VB. Can you port it to c++ or javascript?

Nah - it'a a complete rewrite...
I got lost with the software part of this thread. I have several of the smaller size bits. Of most importants are the ones that go with taps that I use. When I need a #53 bit, I check the chart for diameter and check the bits with a dial caliper. I find that I actually only use a few sizes for the most part. A good tap and drill chat is handy. I laminated mine. Also to go along with drill size, I find its better to built with components that will match your tooling.
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