Commonly used Drill bits, taps, and measurements

**acerocket** · 09-03-2010, 06:12 AM

Marco, you still sound really confused on this. Bear with me and I will try to explain a little.

A typical 'American' screw is given with a number, a thread pitch and a length. For example, 10-32 x 13/32 screw as you posted. You have incorrectly type it as 10/32. This mistake is an important one. The dash (-) tells you that it is not a dimension but the screw callout. 10 is the numner size of the screw. In America, screws under 1/4" are given a nmber to identify their thread diameter. In this case, it is a number 10 which means the screw thread (major) diameter is .190 inches (or 4.826mm). The second part of the name after the - is 32. This is the thread pitch (number of complete threads in a 1 inch long screw). It has nothing to do with the actal length of the screw, just tells you how coarse or fine the threads are. For 32 threads per inch (tpi), that means there is .03125 inches between the 'peak' of each thread on the screw (or .798mm). The final piece of information is the length of the screw - usually expressed as a fractional number. 13/32 inches in this case. To get the decimal length, simply divide 13 by 32 which equals .40625 inches (or 10.319mm). In looking at the charts you posted, for a 10-32 screw, you need to use a #21 drill bit. This bit is .159 inches in diameter (or 4.0386mm). If you notice, .159 inches is less than the .190 inches of the screw diameter. You want the hole drilled to be smaller than the screw so you can tap it correctly.

In your case, if you want to drill and tap for a 10-32 screw, you need a 4mm drill as it will be the closest to a #21. I don't know how much all this will help you as I don't know if you will be able to get an Imperial tap in your country. If you want to go all metric, I would get a M5x.8mm screw by 10mm long and the correct M5x.8mm tap and 4.2mm drill bit to tap the hole for it.

If you are still confused, please PM me and I will try to help you out a little more.

**Marco** · 09-03-2010, 07:11 AM

Thanks alot for your effort, I really do appreciate it!!! But I am still a bit confused... I thought it would be as easy as I wrote, but is my conclusion wrong? About the:

"Now take the Anakin tube, that is totally empty. Drill out the hole for the blade retention screw with an 11/64" drill bit. After doing this, the thumbscrew should slide easily into the hole."

if I look up 11/64" in the wikipedia chart it says that 11/64" are 4.3656 mm or 0.17188 inches... So I just have to find a drill bit with a diameter that is within the range 4.0 - 4.3 mm right? I am so confused xD
(Cuz I dont think the service of the store will know what a #20 Pilot is...)

**acerocket** · 09-03-2010, 07:46 AM

I am not familiar with the conversion kits as I have never done a conversion. Perhaps they are telling you to drill out the old threads in the empty hilt to allow the blade screw to pass through the empty tube without needing to be threaded. That way it will thread into the conversion adapter. If that is the case, then I would just look for a 4.5mm drill for that.

**Lord Maul** · 09-03-2010, 09:17 AM

You're right, Erik.

That part of the tutorial is telling you to drill through ONLY the hilt, NOT the conversion kit. Since the kit is threaded, the screw can pass through the hilt with no harm done.