# Thread: Commonly used Drill bits, taps, and measurements

1. 10-32 refers to the thread pitch and diameter in mm of the hole. The fraction refers to the drill bit, so 10 threads and 32 mm wide on the hole IIRC.

2. I think you have that backwards Shadar. The first number refers to the size , the second to the thread pitch. a 10/32 is a number 10 screw with 32 threads per inch. Also that has nothing to do with the drill bit size. For a 10/32 screw you use a 5/32 or number 21 sized bit. These numbers are for US only they are called SAE. This stands for Society of Automotive Engineers who created the sizing in the early 1900's. This can be confusing when also dealing with metric sizes.

3. Ok... But how am I suppose to find the right drill head to drill in the hole in my anakin fx saber that I want to convert? I guess I have to test a few that fit inside the hole of the kit right?

4. 10-32 does not mean 10/32 inches

It is the #number of the screw and the thread count per inch.

The pilot hole used prior to tapping a 10-32 screw is a #21 drill bit

If you look up drill bit sizes online, you should be able to find the nearest metric equivalent drill bit. You can search for TAP sizes in SAE and find which drill bit to use for the pilot hole. Then compare SAE drill bit sizes or #s for your closest metric equivalent drill bit.

If your metric is too much smaller, you will have difficult time tapping due to overly tight pilot hole. If your metric is too much bigger, you will either get partial depth threads, or no threads at all.

the 13/32" measurement does indeed mean 13/32nds of an inch. Your conversion is then of course 25.4mm per inch

And yes, the numbering schemes are complicated, confusing and generally antiquated. In many cases, they are carry overs from a hundred years ago or more. However, in the US, unless you went to college to be a scientist/engineer, you don't use metric very much (lightbulbs, strangely, are an exception. Nobody ever runs to the store to purchase a 1/10th Horsepower lightbulb)

water pipe and copper tubing have "nominal" sizes which are NOT their actual size, but rather indicate what size they would be compatible with if you tried to match them up with old cast-iron pipe, for example.

5. Originally Posted by Marco
Ok... But how am I suppose to find the right drill head to drill in the hole in my anakin fx saber that I want to convert? I guess I have to test a few that fit inside the hole of the kit right?
There really is no conversion. That's why both still exist over 100 years later. A 5/32 drill bit for example is about 3.8mm. if you used a 4m it would be to big, and a 3m is to small.I would order the right SAE size bits and taps online.

6. A little history/info.

They are one of the first places I have seen that actually gives the formula for how the number screws get their size. I knew it from college, but have never seen it on the web before.

7. I found this chart online --> http://bobmay.astronomy.net/misc/drillchart.htm I don´t really know if it is usable for my purposes...

But it says for example: 5/32" are 3.9688mm so lets say if I find a 3.5 - 3.9 mm drill head in my local hardware store it should be usable to tap the hole right?

Edit: Or somehow I could use this one here --> http://en.wikipedia.org/wiki/Drill_and_tap_size_chart
Hm I just ordered a Anakin con. kit hopefully I will be able to tap the hole for the blade retention screw ... :/

Double Edit: "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...)

8. 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.

9. 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...)

10. 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.

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