Torx bit specs

[dguy]

Anyone have a chart or other resource which relates the T-## sizing of torx fasteners and bits to the bit's diameter?

I have a female 12-point fastener to deal with, which is approximately 0.53" in diameter when measured at opposite "points".  A T-50 bit is way too small; I'd like to find the correct-sized bit for this thing...

[FieroBUZZ]

When in doubt on these things, I take a piece of play dough and try to get a copy of the hole in the fastener.  Them I try to match it up at a tool type place. 

The operative word here is "try".

[2ML67]

Now who all here is not surprised that Gary plays with play dough.
Torx did come in many sizes try a t-55 to see if it fits, I know that is the size on 88 calipers. Dan

[GoFast88]

Yep
Since there are not T-51, 52 etc. T-55 is the next one higher.
I don't know if there is such a thing as a "metric " Torx. Don, where did you find this fastener??

[dguy]

When in doubt on these things, I take a piece of play dough and try to get a copy of the hole in the fastener.  Them I try to match it up at a tool type place. 

The operative word here is "try".

Ha... never thought of that.  Not sure if we have any around the house, but my 2-year-old nephew has lots.   

Don, where did you find this fastener??

See the latest entry in my build thread, added just now.  It's a retaining "nut" which is preventing me from removing one of the output shaft bearings.

[GoFast88]

I had a chance to measure my Torx set. The lands were measured with a Mitutoyo and the groves with a "mastercraft special". The T-55 was 0.4385 and 0.3. The T-60 was 0.516 and 0.41.   Hope that it helps out.

[dguy]

I had a chance to measure my Torx set. The lands were measured with a Mitutoyo and the groves with a "mastercraft special". The T-55 was 0.4385 and 0.3. The T-60 was 0.516 and 0.41.   Hope that it helps out.

Thanks Brian.  Give or take a few hundredths for different hands and tools, the T-60 appears to be a close fit.  Off to Princess Auto I go!   

[GoFast88]

You had better bring your credit card with you.  They are not cheap.    I don't mind lending mine out for a short period of time. I will be home at 5pm. Let me know