what actual size is a #79 drill bit?

If you get really stuck, ask your jeweller where he buys his tools.
Hardware stores rarely stock anything in the sizes we use. They may go down to a #4-40 screw (I think they're used in electrical sockets) but I only found one with #2-56 and I bought a box of a hundred or so -- I'm almost out of them.
 
How tiny? Try itsy bitsy!

Any hobby shop worth their salt will have them, as will train shows and Micro Mark too. Even the "late great" Great American train store in malls had them. Believe it or not, thats where I got mine!
 
Truer words were never spoken!

I've broken a few drilling grab iron holes. Be sure to get a good pin-vise and mount the bit close to the end so that only a little sticks out, that way you'll minimize breakage.
 
Conversion charts

Number Sizes


Letter Sizes

Most drill sets stop at #60, which in 1/87 is pretty durned big :( There are sets to augment these regular sets that run from #61 to #80. Also you can buy individual drills. Locally, you might check your dremel supplies at the hardware or home improvement store. Dremel has a set, but I don't think it goes that small.

Here are some suppliers I have not ordered from:

http://www.discount-tools.com/drillsindexmain1.htm

sets and individual bits - High Speed (HSS) is probably best for most of our uses

http://www.drillbitcity.com/index.htm

They have small numbered set for under $10, resharpened. Caution: these are carbide, which is very sharp and able to drill hard materials, but it is brittle and probably not suitable for hand held power drills. Maybe OK in a pin vise if you have a steady hand, or a drill press with caution. Break one off in you work and the games over.

http://wttool.com/Merchant2/merchant.mvc?

Site is slow as molasis, but the price is right on HSS # bits, 27 to 54 cents range.

Of course, there's always Harbor Freight if htay have them that small:

http://wttool.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=WT&Category_Code=01420006p

TiN plated is OK, if it's HSS underneath and you sharpen it, it's HSS again instead of TiN. Probably makes no difference when drilling softer materials.

Cobalt is probably overkill, unless you plan to drill into harder metals. My experiance has been that it's easy to work with, similar to HSS.

Carbide and carbide tips use with caution.
 
I have found http://www.mcmaster.com/ to be an invaluable source for small screws, drill bits, brass tubing, etc,etc. The site is easy to navigate and their prices for parts are a whole lot less than Micro-Mark, Walthers, or your local hardware store.
Angus Macdonald
 
Good to know about carbide...it does break, and when I mean break, I mean shatter...I am glad I at least wear glasses, though I wish I wore more with these things...I use them mostly with my drill press, but I have been using them to drill out some metal posts on IMEX trucks...I have evnen shattered large bits drilling out that metal...I bet they would hurt in the eye...
 
As you have found, your local tool supplier isn't going to satisfy hobby needs.
Just looked up the mcmaster site. It's going to take some time to sort through. Wish I was younger.
 
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