From Newsgroup: rec.crafts.metalworking

I recently went through some iterations making a wire bending tool for a customer.-a I sheared some stainless dowel pins in testing.-a Then I tried some alloy steel dowel pins and made a series of test bends with
material and applications far hard than the customer claims he's doing.-a
The customer managed to shear one of those.-a Finally I went to high
speed steel drill blanks.-a Close tolerance set in Loctite 640 cut just
barely long enough to do the job to minimize leverage against the pins.-a
The math says I have a fair safety margin.

Of course HSS drill rod doesn't come in nice convenient standard dowel
lengths so I had to cut the pins with an abrasive tool.-a A little fiber Dremel disc on a rotary hand piece.-a Of course that leaves a burr which
I ground off with a diamond conical point, but the diamond reacts with
steel at grinding temperatures and of course only lasted long enough to
deburr a few pins.

It seems that small rotary grinding points exist in a conical with CBN,
but actually finding them for sale is being a bit of a struggle.-a
McMaster seems to have no small CBC grinding points, and Penn Tool only
has cylindrical.

Of course I sent one replacement rotating assembly off to the customer
(4 pins its double ended) and then I finished one for myself.-a I would
like to make small batches of these for customers, but I don't want to
have to replace a diamond conical grinding point after every few pins.-a
who actually stocks them online?-a Searches just keep coming up with diamond.-a I don't want diamond.

A 1/4 inch conical with a 60 degree point and an 1/8 inch or 3mm shank
would be ideal, although I do have a few rotary hand pieces with 1/4
inch collets as long as the grinding point isn't so big or gets in its
own way or blocks my view while working.
--
Bob La Londe
CNC Molds N Stuff

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From Newsgroup: rec.crafts.metalworking

"Bob La Londe" wrote in message news:114bi6f$3fg1k$1@dont-email.me...

Of course that leaves a burr which I ground off with a diamond conical point, but the diamond reacts with steel at grinding temperatures and of course only lasted long enough to deburr a few pins.

I've read that diamond can survive grinding steel as long as the surface
speed is below 3600 (or 4000?) SFPM. Perhaps that's how they last on a Drill Doctor.

Dremel universal brush motors can be slowed down with a Variac. I haven't tried a lamp dimmer.

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From Newsgroup: rec.crafts.metalworking

On 7/28/2026 5:55 PM, Jim Wilkins wrote:

"Bob La Londe"-a wrote in message news:114bi6f$3fg1k$1@dont-email.me...

Of course that leaves a burr which I ground off with a diamond conical
point, but the diamond reacts with steel at grinding temperatures and
of course only lasted long enough to deburr a few pins.

I've read that diamond can survive grinding steel as long as the surface speed is below 3600 (or 4000?) SFPM. Perhaps that's how they last on a
Drill Doctor.

Dremel universal brush motors can be slowed down with a Variac. I
haven't tried a lamp dimmer.

You telling me to keep my foot off the pedal?
--
Bob La Londe
CNC Molds N Stuff
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From Newsgroup: rec.crafts.metalworking

On 7/28/2026 5:40 PM, Bob La Londe wrote:

I recently went through some iterations making a wire bending tool for a customer.-a I sheared some stainless dowel pins in testing.-a Then I tried some alloy steel dowel pins and made a series of test bends with
material and applications far hard than the customer claims he's doing.
The customer managed to shear one of those.-a Finally I went to high
speed steel drill blanks.-a Close tolerance set in Loctite 640 cut just barely long enough to do the job to minimize leverage against the pins.
The math says I have a fair safety margin.

Of course HSS drill rod doesn't come in nice convenient standard dowel lengths so I had to cut the pins with an abrasive tool.-a A little fiber Dremel disc on a rotary hand piece.-a Of course that leaves a burr which
I ground off with a diamond conical point, but the diamond reacts with
steel at grinding temperatures and of course only lasted long enough to deburr a few pins.

It seems that small rotary grinding points exist in a conical with CBN,
but actually finding them for sale is being a bit of a struggle.
McMaster seems to have no small CBC grinding points, and Penn Tool only
has cylindrical.

Of course I sent one replacement rotating assembly off to the customer
(4 pins its double ended) and then I finished one for myself.-a I would
like to make small batches of these for customers, but I don't want to
have to replace a diamond conical grinding point after every few pins.
who actually stocks them online?-a Searches just keep coming up with diamond.-a I don't want diamond.

A 1/4 inch conical with a 60 degree point and an 1/8 inch or 3mm shank
would be ideal, although I do have a few rotary hand pieces with 1/4
inch collets as long as the grinding point isn't so big or gets in its
own way or blocks my view while working.

I found a CBN conical grinding point finally. It's a little smaller than
I wanted, but that's better than to big. They aren't cheap, but in my
searches I found conical grinding points (all cylinders) that cost a lot
more. They are not particularly expensive either. If they work, it's not
cost prohibitive. https://triaticinc.com/cone-tool-11-64-head-diameter-x-60-degree-angle-x-1-8-x-2-oal-140-170-grit-cbn/
--
Bob La Londe
CNC Molds N Stuff
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From Newsgroup: rec.crafts.metalworking

"Bob La Londe" wrote in message news:114e4ev$19l57$1@dont-email.me...

Of course HSS drill rod doesn't come in nice convenient standard dowel lengths so I had to cut the pins with an abrasive tool. A little fiber Dremel disc on a rotary hand piece. Of course that leaves a burr which I ground off with a diamond conical point, but the diamond reacts with steel at grinding temperatures and of course only lasted long enough to deburr a few pins.

My small lathe accepts a 1/2" Jacobs chuck with a 1/2"-20 thread mount directly and I made a 1.5"-8 to 1" collet adapter for my big lathe for a larger Jacobs lathe drill chuck. The aren't ideal for turning but can hold
any size round or hex in their range for filing, grinding and polishing.


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