TORX SCREW sizes.

[leigh47]

Torx screw wrenches are numbered (TX-10 etc.) Can anyone tell me how to actualy measure the screw or wrench to establish what number it is? (I dont mean by trying which wrench fits the screw and then looking what number it is!)

[gumboot]

The numbers seem to have been decided upon by the original manufacturer, Textron and don't seem to have been derived by any specific method.

There's a table in the following online pdf document which gives the sizes involved:

http://www.textronfasteningsystems.com/PDFs/to rx.pdf

The table should allow you to read off the TX size from the measurements of the screw.

[leigh47]

Thank you gumboot. I suspected it was not a simple measurment as I have measured some and there was no logic about the size numbers and the measurments. The site you refered me to is interesting and the table will be usefull.( If the screw is already fitted however it will not be possable to measure the thread size and match to the table.) Thanks again it is just what I wanted to know.