Harold Hall


 Changewheel charts




Two lists are included, one for a lathe having an imperial leadscrew and the other metric. Do though note that in the case of imperial threads the results are given in terms of TPI (threads per inch) and metric threads in terms of pitch (the distance between adjacent turns of the thread)


The values have been extracted from a computer program that calculates the result for every possible combination, in excess of 66,000 when 14 different gear sizes are available. From this the program eliminates those less than 6TPI and greater than 50TPI  resulting in  37,293 combinations being listed within that range.


In the case of metric threads, around 37,000 combinations result from 13 gears with 24162 of these being listed for all the pitches between 0.5mm and 4.0mm.


Should you wish to have access to this data without having to visit this web site you can make copies of the files to your hard disk for each range of values by using one of the following methods.


Method 1

1 Right click on the data in the frame, not the whole page.

2 Click on View Source.

3 The data opens up in Notepad, or other wordprocessor.

4 Click on File, then Save As, and navigate to your chosen folder in which to store the list. You can chose to retain the file name or change it as you wish.


Method 1 works in Internet explorer but not in some browsers. Typically, if you use Firefox or Opera, you may have to use a process based on the following. The explanation is though again for Internet Explorer.

Method 2

1 Right click on the data in the frame.

2 Click on "Select All"

   Or run your mouse pointer from the top of the list to the bottom with the left button held down.

3 Right click on the data in the frame once more

4 Click on Copy

5 Minimise your browser

6 Open up Notepad, or your preferred wordproccessor

7 Open up the edit menu and click on Paste.

8 Save using a suitable file name and location.

For this I would suggest typically "Upto07.***" where 07 is for the list that goes upto 7.000 TPI. *** being txt, doc or whatever your wordprocessor uses.


Whichever method is used the lists should preferably saved and viewed using a mono spaced font, "courier new" being an acceptable choice.


The permission to copy this is for personal use only  The complete list as presented is though copyright for other uses



If you consider printing out the lists do bear in mind that a single list is likely to require some 40 to 80 pages depending on the number of combinations and the size of the font used. For all of the lists we are talking many hundreds of sheets.

Lathe Changewheel combinations

and the thread that results.

                                                                        Harold Hall



Screw cutting
Metric changewheel combinations
Lathe changewheel combinations