What drill sizes do you use most often?

[Jeff-Birt]

I've been using Eagle/PCBGcode/MachIII for a couple years now for milling PCB's both at my day job and for personal projects. I started buying my bits from Precisebits.com about the same time (Pricesbits.com is thinktink.coms online bit sales site.) One thing that was a bit daunting for me when I was starting out was trying to figure out what sizes of drill bits would work best. You always get a discount for purchasing 10 or more of a single bit but I did not want to buy a bunch of them I would wind up not really needing.

Recently PCBGcode added 'drill rack' files which let you specify what drill sizes you have and it automatically converts the called for sizes to the sizes you actually have.

Even more recently I started a small business (cnczone.com) and one of the things I sell is the Precisebits.com bits. (As a customer of theirs I was always really happy with all the stuff I got from them and their great support.) Anyhow, it occurred to me that a good way to save my fellow PCB millers some money would be to offer kits of bits that have something like, 3 trace isolation V-bits and 2 each of three different drill sizes.

I know what sizes of drills I use most often but want feedback from others as to what drill sizes they find most useful. So, if this sounds like a good idea or bad idea let me know. I'm hoping it will make it easier on the new guys starting out with PCB milling and allow everyone to save some of their hard-earned-money by getting the 10-bit discount on the kit.

Oh, and as was suggested to me by one the guys on the PCBGcode.org forum, I'll include the drill rack files with the kits to make it super easy to take advantage of the drill rack feature.

[Jay C]

I use .125" for stand off holes and if doing double sided
I use #60 (.04") holes for any header holes
I use #68 (.031) for all LED, IC pin, resistors

I use a 60-degree V-bit for isolation routing
I use a Solid carbide bit with diamond pattern for milling the board outline
All are .125" shank

Jay

[Jeff-Birt]

Thanks Jay!

[Jeff-Birt]

Background:
One of the most difficult tasks for me getting started with PCB milling was knowing what size drills I should get. There is always a decent price break when you order 10 or more of one size but I did not want to get stuck with 10 bits I would never use. I have been buying my PCB routing bits from PreciseBits.com for a couple of years now as they seemed to be the best value for the money (not the cheapest). When I started my website I signed up right away to be a distributor of the PreciseBits line.

They already had sets of drill bits made up for common PCB routing tasks, but they were kind of hidden on the parent companies website. Working with them I came up with a few additional 'Starter Kits' that include two 60 deg. 'V' bits for trace isolation. Information about these kits follow.

I have the PCB drill kits and started kits in stock now! I'll be working on the drill rack files for PCBGcode this weekend. Here is a basic rundown on each kit:

Heart Range A: Through hole boards, inch sizes
Heart Range B: SMT boards, inch sizes
Metric Heart Range: Through hole board, metric sizes

The Starter Kits A, B, Metric are the same as above with two of the larger drills replaced with 60 degree V-bits. You can find more information here: http://cnczone.com/shop/Precise_Bits_86618.aspx

For a very limited time, I'm including the ZrN (much better then TiN) coated V bits in the Starter Kits. The ZrN coating produces a much smoother cut in the copper and will last 2-3 times as long.