Lms Tool Bits Have An 18 -19 Degree Angle - Any Significance

[Epictetus]

The included angle is about 71 - 72 degrees, making that a relief angle of about 18 - 19 degrees.

lms shop recommends a front and side relief of about 10 degrees.
For steel and aluminium a top rake of about 12 and a back rake of about 8.
For brass the rake angles are much less, or even zero.

So why are these ground to 18 - 19 degrees?

 

[higgite]

I'm guessing it has something to do with the manufacturing process, but that's just a guess. It's immaterial in the long run, though. Those tool bits aren't intended to be used straight out of the package. They are blanks for the user to grind to whatever form suits their need, e.g., a left or right hand turning tool, a 55 or 60 degree threading tool, a grooving tool, etc., etc., etc.

Tom

 

[4GSR]

I can show you 30 different brands of HSS and the angles will vary. There is no set standard to this angle. Make it anything you want to meet your needs.

 

[Epictetus]

Tom and Ken,
Thanks for taking the time to respond.
Solves one mystery for me.
Cheers!