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[Looking4] Small core drill


#1

I’m looking for a small core drill (or similar) that will yield a
~1/4" core (this is the important bit) and that either can be made to
have a very fine pilot drill or something that will spot the centre
of the resulting core so it can be pierced later.

The thing does not need to be diamond coated as I’m coring fossil
ivory, but so far all I’ve found in that size range has been diamond
edged tooling and when you get down to that small a core size there
is no provision for a centre spotting system or pilot drill. The
ultimate aim is to make a few dozen ivory beads, but being in
Australia I can’t import anything anymore (even fossil ivory is out
now), although I did buy a few pounds of scrap pieces about 10 years
ago so I have the raw materials, just no way to make the beads as
yet.

I suppose that if push comes to shove I could make a tool in my
lathe that will use a 1mm pearl drill for the pilot and have a steel
blade that is either “as machined” or hardened in some way (depends
on what I can find to make it from). I expect that for tooth profile
I wouldn’t need anything fancy, but swarf clearance would be a
priority as would ventilation as I wouldn’t want to burn the bead
blank in the cutting now would I! As you can see finding an off the
shelf tool is much preferred…

Thanks everyone.
Cheers, Thomas Janstrom.
Little Gems.
http://tjlittlegems.com


#2

Can’t you just use a good high speed carbide drill??

John Dach


#3
you get down to that small a core size there is no provision for a
centre spotting system or pilot drill 

Thomas, there ain’t no such animal for stone - or let us say I’d
love to see such a thing. There’s hole SAWS, and there are heavy
duty versions that are beyond the hardware store variety. Check the
usual machinists places. But those aren’t for stone. Just a standard
twist drill in the center…

Set up your work in a mill or drill press, center drill it, change
to core drill without changing setup, cut, done.

http://www.donivanandmaggiora.com


#4

John,

Thomas, there ain't no such animal for stone - or let us say I'd
love to see such a thing. There's hole SAWS, and there are heavy
duty versions that are beyond the hardware store variety. Check
the usual machinists places. But those aren't for stone. Just a
standard twist drill in the center... 

I found something that is “almost” just right (but no good for stone)
for the job

http://www.hougen.com/cutters/sheetmetal/Rotacut.html

these have two options, one uses a centre drill (1/4" by the looks of
it) the other has a spring loaded floating centre point that locates
the saw.

If I was going to use one of these I’d use the floating point
version, but the width of the kerf is rather large and I’m not that
keen on wasting fossil ivory (incidentally the hardness of this stuff
is between 2 and 3mohs), so I will keep looking, it’s not urgent as
yet.

Cheers, Thomas Janstrom.
Little Gems.
http://tjlittlegems.com


#5

try lasco, their website is lascodiamond.com

warm regards