> screw-machine length drills with a 135* split point
...
> Also solid carbide drill is more rigid than HSS.
As usual, a quality suggestion from Mr. Clement! Thanks!
When I first started looking through the Travers master catalog a few months ago, I was thinking, "why are there so many different kinds of X" where X was nearly anything that I was looking for.
I'm starting to understand why: there's a *reason*.
Yep, there they are, on p. 4. But no solid carbide versions. use-enco.com has carbide ones, as individual bits. (Hmmm... A 10-to-1 difference in price for different USA sources of the same size. More homework for me.)
> 90 degree spot drills work nice
> drill radius in depth + .005 will leave a nice chamfer on the finished hole
Yes, those 90s do seem to be great for chamfers. That's just too tempting to ignore.
My research suggests that the angle of the spotting drill should be no less than that of the drill (although I've seen opinions both ways, I'm preferring the recommendation from a spotting-drill manufacturer.)
But since 135* split-point drill bits are available individually, I can try a few the next time I place an Enco order.
Kerry  |