Machining a high tensile bolt.

[Smallfry]

For my latest scheme, I need an M10 by 130mm high tensile countersunk bolt.

Because I am too tight, want instant (ish) gratification, AND having a boxful of 130mm hex headed jobbies that have been cluttering up my life for years, I thought I might put one in the lathe and turn a countersink on it.

It doesnt matter that there is no purchase for any sort of tool, as the head will be tack welded in position.

My concern is , will any of this affect the high tensileness. I assume the bolts are made of a different material than plain mild steel.

 

[Pete.]

Nope have at it.

 

[Kram]

As above however, what grade of high tensile is it? 8.8 seem they can be any grade if carbon steel and machine quite acceptable. Better grades, 10.9 and 12.9 seem to be made of 708m40 or 817m40. The added chrome makes them noticably more challenging to turn and I would hesitate to use a die on one.

 

[Smallfry]

As above however, what grade of high tensile is it? 8.8 seem they can be any grade if carbon steel and machine quite acceptable. Better grades, 10.9 and 12.9 seem to be made of 708m40 or 817m40. The added chrome makes them noticably more challenging to turn and I would hesitate to use a die on one.

They are 8.8 grade, I just didn't want to use stainless A2 or mild steel. Application doesn't warrant anything better. Hopefully