Thread Sizes

[Fast_Eddie]

Hello,

I'm about to purchase some taps and dies to clean up some bolts, etc, and retap some captive nuts in the FC.

Am I correct in assuming that the early Holdens are UNC & UNF thread?

Regards

Edward

[Effie C]

Thats correct Edward, UNC & UNF, would suggest some die nuts too if you can afford them.
John M

[Fast_Eddie]

John,

I purchased taps and dies, and cleaned up a few nuts and bolts. Now the nuts spin onto the bolts!

Simple pleasures....

Seeing it was 20 years ago that I completed year 8 metalwork, I'm a little bit rusty on some of the tecnique with tapping new holes. What's the relationship between the hole diametre, and the tap that is required to tap it.

ie, Do I bore a 5/16 hole for a 5/16 tap, or should it be a 1/4 or 9/32?

No doubt there is a published table that identifies this? Any advice would be appreciated.

Regards

Edward

[craiga]

Edward,

I did a quick search and came up with a figure 55 -75% of the major diameter as depicted in the image below.



You could also have a look here http://www.cartech.com/machining_zone/tapping.html which has enough info to keep you amused for hours on end. ;D Even has formulas!!! WOOHHHOOO ;D



Cheers,

Craig.

[Murray]

P&N (cutting tool makers) put out a really good chart that covers a wide variety of threads but I am not too sure where you could get one. Perhaps Blackwoods or one of the other engineering supliers.