At what wire gauge does a 135 degree split point jobber bit STOP being split
point? I checked my sizes 1 thru 60 and found that size 44 and down (to
size 60) were not split pt despite me ordering direct from the manufacturer
that they be split points. Sizes 43 to number 1 are split points.

I cannot find anything in the machinists handbook or on the ANSI website.
Can anyone shed light on this OR is this something specific with the
manufacturer. They are in Czech republic and the English salesman from
there is on holiday until April.

Thanks for any help

HeadHunter.

Point splitting of the very smallest sizes probably varies with the
manufacturer. What it comes down to is the precision of the cut ground on
the drill bit and skill of the operator. Below a certain limiting size it
becomes impossible to make the "split" without excessive damage to the
point.

Bob Swinney
"HeadHunter" wrote in message
...
At what wire gauge does a 135 degree split point jobber bit STOP being
split point? I checked my sizes 1 thru 60 and found that size 44 and
down (to size 60) were not split pt despite me ordering direct from the
manufacturer that they be split points. Sizes 43 to number 1 are split
points.

I cannot find anything in the machinists handbook or on the ANSI website.
Can anyone shed light on this OR is this something specific with the
manufacturer. They are in Czech republic and the English salesman from
there is on holiday until April.

Thanks for any help

HeadHunter.

"Robert Swinney" wrote in message
...
Point splitting of the very smallest sizes probably varies with the
manufacturer. What it comes down to is the precision of the cut ground on
the drill bit and skill of the operator. Below a certain limiting size it
becomes impossible to make the "split" without excessive damage to the
point.


Also, why would one want a split point on such small drills? I find the web
is only a real issue on drill sizes above ~3/16" or 1/4" anyway.

Regards,

Robin

In article ,
HeadHunter wrote:
At what wire gauge does a 135 degree split point jobber bit STOP being split
point? I checked my sizes 1 thru 60 and found that size 44 and down (to
size 60) were not split pt despite me ordering direct from the manufacturer
that they be split points. Sizes 43 to number 1 are split points.

Mine transitions between #52 and #53. It is an index of cobalt
screw-machine length bits.

I had not thought to check before your posting -- and I had to
dig out the 10X jeweler's loupe to be sure.

But I believe that my random collection of sold carbide printed
circuit drill bits holds the split point down to smaller sizes.

I cannot find anything in the machinists handbook or on the ANSI website.
Can anyone shed light on this OR is this something specific with the
manufacturer. They are in Czech republic and the English salesman from
there is on holiday until April.

Well ... my set is a "Made in USA" set, as sold by MSC a few
years ago -- with a good HUOT index.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Any drill could be reground with split points. There seems to be a
misunderstanding among some that the points are attained or added by making
a grind to almost the center of the web (at the back of the flute).

That's not how split points are attained. The back grind (approximately
parallel to the flute spiral) is done first, then the cutting faces are
brought back to where the points are optimized.

I discovered this method back in the '80s using an industrial toolroom drill
grinder. I don't remember the maker of the machine, but it had numerous
precision holders for almost any common drill size.
I used to be able to make decent split points by hand when my eyes were
better, but I have a difficult time getting good results now even with a
good 3 diopter magnifier at the bench grinder.

And for the commentary in another post about whether drills are bits or
not.. they are not.
It's made it's way into the language, but that doesn't mean it's correct.
A bit is something that goes in a horses mouth, said my machine shop
teacher.

WB
..................


"HeadHunter" wrote in message
...
At what wire gauge does a 135 degree split point jobber bit STOP being
split
point? I checked my sizes 1 thru 60 and found that size 44 and down (to
size 60) were not split pt despite me ordering direct from the
manufacturer
that they be split points. Sizes 43 to number 1 are split points.

I cannot find anything in the machinists handbook or on the ANSI website.
Can anyone shed light on this OR is this something specific with the
manufacturer. They are in Czech republic and the English salesman from
there is on holiday until April.

Thanks for any help

HeadHunter.






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