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Design a dremel hammer bit


#1

All,

I’ve been studying on the internet how to set stones with bezels,
and I can clearly see the advantage of using a hammer handpiece
rather than burnishers to smooth the metal over the stone.

On the other hand, I fully realize that setting up with a foredom
hammer handpiece requires about $500.

Since I am in bootstrap mode I would rather improvise an equivalent
effect rather than earn it. But the GOOD news is, I have a 4-axis
CNC tabletop mill, so I can (in theory) create a rotary bit for a
flex-shaft.

My question to you all is this: if I wanted to create a rotary bit
that would act as a hammer, what shape should the bit be?

It would seem that a swas (with apologies to Jewish people, since I
am Jewish myself, but I only know one word for the shape) stika,
centered on the shank of the bit, would provide a balanced set of 4
hammers to close the top of the bezel over the stone.

But classical physics is not my strong suit, and so I wonder if any
of you out there can think of a more ideal shape to create as a
rotary bit for this purpose.

Thanks in advance,
Andrew Jonathan Fine


#2

Andrew, you don’t need that fancy shape. Just a cylinder shape,
except with facets, so the thing ends up as a hexagon, or other
polygon. The fewer facets, the stronger the action. You don’t need
to make them either. Look in the Stuller tools catalog, and you can
find these rotary burnishers made in carbide, ready to go.

However, be aware that these are a poor imitation of the action of a
hammer handpiece. No matter how you make the rotary tool, the action
is a wiping/side to side burnishing action, rather than an inline
impact. The effect on the metal is quite different. The rotary
burnishers sold are usually presented as good means with which to
burnish out porosity in castings, and they work well for that. For
setting stones, they’re less effective.

The simplest rotary burnisher (or hammer if you like) is simply a
bent bur. Take an old dull busch bur, remove the original working
end. Turn it over, heat the last quarter inch or so of the back end
of the bur and bend it to a short L shape. round off and highly
polish the end of the short leg of the L. In use, the long end goes
in your dremel or flex shaft chuck, and the short end, flying around,
can burnish out pits and defects in a casting. If you want to get
fancy, make one where the working end is a bit of carbide soldered
on, equally rounded and highly polished. That gives less friction
with the metal, and lasts longer. With some care, and lubricant, you
might be able to move bezels too. But I doubt that this will be a
strong improvement over just using a burnisher, or hammer and punches
for heavier metal.

You might consider one of the air hammers. There’s a tool Harbor
Freight sells for engraving on glass, etc, which is air driven off of
any compressor. Made under their Chicago Electric brand, I think…
Intended for stipple/impact engraving, some people use them for stone
setting as a hammer. I’m not a great fan of them, but they’re not
that expensive, and perhaps that would serve your needs if you’ve got
compressed air available.

Peter


#3

We used this sort of hand-made bit starting in 1994It was a balanced
and slightly polished set of 4 hammers. Primarily we used it to
muscle over metal where there was porosity to compress the area.
Great tool !

M. Mersky
Minneapolis in January is thirty below. In June a heat index of 105
Boots to bikini’s !
www.mmwaxmodels.com


#4

Andrew,

Many, many years ago I was shown the most clever and useful tool for
pounding out porosity, and even pushing a bezel up around a stone. I
have made many of these over the years, given a few away to students,
and have probably 3 of them in my bench of different shapes and
sizes. What is this tool?? It’s a bent nail, polished on its end.

Really.

I take an old broken bur or heavier round stock, like a common nail,
and anneal it so I can put a fairly sharp 90 degree bend on it in the
jaws of a vise. The longer end is the shank, and I then saw off the
remainder to leave just a 5 mm or so “leg”. That short leg gets
slightly rounded with files, sandpaper sticks, and finally polished
on the tip. This tip can be custom shaped to get into tight areas,
etc.

When this little “beater” is mounted tightly in your flex shaft, and
both hands braced on your work, that spinning “leg” works great to
pound the metal with great force. You should watch closely to see
where each stroke is landing for best control.

There are other “margin rollers” or beaters with rounded lobes
around the outside edge I’ve seen in catalogs, as well. Be sure to
wear safety glasses when working with fast-spinning tools!

Jay Whaley
www.whaleyworkshops.com


#5
My question to you all is this: if I wanted to create a rotary bit
that would act as a hammer, what shape should the bit be? 

Andrew, you’re re-inventing the wheel, and I hesitate to say it
won’t work, too, but it at least won’t work very well. Good and
confusing… :wink:

Here’s one: http://www.ottofrei.com/store/product.php?productid=8978

Pasting that, Jo-Ann said, “We have that…” Which I didn’t know…

What I (and many others) use for the same purpose is a bent bur
shank with a ground and polished tip. Effective and free…

But it’s not for setting, and for me, anyway, it just doesn’t work
for setting at all. It’s for pounding out porosity, at which it
excels, and whatever else anybody uses it for - scratches…

That’s because it’s not a hammer in the real sense of the word, it’s
a burnisher. Yes, it “pounds”, but not in the same way. You need a
reciprocating hammer to hammer. The power of a reciprocating hammer
is directed in the line of the shaft, the rotary hammer is a rotary
force, by and large…

It’s not just theoretical, I’ve tried it and it really just doesn’t
work nothing like a true hammer handpiece, anyway…


#6

Andrew,

Otto Frei has a rotary burnisher, part number 118.084. It’s a common
shape. They also have another model with 4 sides/corners. Other
suppliers have similar tools.

Mike DeBurgh, GJG
Henderson, NV


#7

The “L” shaped bent bur seems to be a very universal tool. I would
only like to add that it has the potential to be a very dangerous
tool, not only for the user, but for the jewelry being worked on.
Smack that baby into a stone and it can do some serious damage in
nano-seconds to even the toughest stones. You don’t want to hit a
finger with it either. That smarts. Trust me on this. You also don’t
want to catch it on a towel or rag. That can make a tightly coiled
mess of the power cord. Or break your wrist.

I have also had these things bend in use right at the collet due to
the unbalance and the fact that annealing it to bend it softens the
whole thing to some extent. The uneven forces acting on it as it hits
the metal are also a force not to be ignored. Using it in a Dremel
tool at anything approaching mid to high speed is asking for a
catastrophic failure of either the bent bur or the collet or both.
Either one bends or fails, it’s coming out of the handpiece. It can
come flying out with some pretty high inertia. They work fine at low
to medium flexshaft speeds, say a couple hundred RPM, but crank it up
to 10,000 RPM and it can become an eyeball crushing missile.

I’m not sure I would join in the recommendation to use one of these
to set stones, especially in a Dremel tool. They would be marginal at
that job at best. The only thing they really work well for is getting
rid of porosity, but even then, if you over-do it the surface damage
on the piece may require a lot of clean up, sometimes requiring you
to go right through the hammered metal and back into the porosity
again. With a very light touch though, they work pretty well at
burnishing surrounding metal into porosity. A hammer handpiece anvil
rounded and polished and worked obliquly in all directions works much
better, for me anyway.

For stone setting, use a polished drift (I make mine out of old burs
and concrete nails) and a chasing hammer to close bezels if a hammer
handpiece is beyond reach. Much more control, a lot less risk to
everything and everyone involved. I set stones that way for many
years. I still do when there is anything more than a slight risk to a
stone. It really doesn’t take that much longer.

Use common sense and eye protection at the very minimum. When using
it with a Dremel tool, steel gloves, body armor and a kevlar face
shield might not be a bad idea.

Dave


#8

swasstikas are an ancient Sanskrit symbol/srchetype that represented
one of the Hindu trimurti, Lord Shiva,way before Hitler usurped it
and bastardized its meaning to reflect his yearnings for world
domination and as a symbol of evil…

…Anyway, you certainly don’t need that intricate of a bit- check
out MAKE magazine’s DIY pages and videos- someone else has done about
the same thing(s) using an allen wrench, at least, and an old riveter
at best ( too complex, the allen wrench wll l work fine), but a
hammer handpiece can be found on some sites as low as 100
dollars…and on ebay occassionally (in metalworking, or dental not
jewelry makng) for less than that…buffalo dental makes a decent one
at about 75.00…not a badeco, or swiss made handpiece but it’ll get
the job done!

You can’t overlook the simple nut on the end of an old bur, or nail
modified to a 90 degree or so angle if you like ( just the nut
rotating in the collet will accomplish beating the metal into
submission!) much like a rotary finishing bit and hole removing
burnisher…

or My favourite is a masonry nail that is simply shaped on a bench
grinder (or with your dremel) to make the neck less thick at the top
than it comes out of the box, Once shaped it makes a flattened "t"
shaped bit that will pound the metal around the stone (particularly
appropriate for pear and marquise shapes, whereas the nut on nail is
better for the round, trillion,trilliant, or emerald shaped stones

It will pound the bezel or tube setting right up around the stone-
but do protect the stone with painters tape or rubberized adhesive as
if not tightly held in your vise or benchmate, can slip if you run
the rotary end of the job too high/fast…a good 10,00 rpm is almost
over kill…it beats the metal as any rub over setting will… simpler
is usually better…rer


#9

I’ve been a jeweler for 30 years now.

Please trust me on this: There is no better tool for bezel setting
stones on this Earth than a gravermach with a burnishing tip,
coupled with a microscope. Watch the metal as it gently approaches
the stone. Don’t worry so much about breakage (knock on wood). Hold
the piece with your left hand (against a bench pin) while you set
with your right.

I’ve come to feel somewhat helpless without it. With three different
studios to work in, I am rarely without my gravermach, but when I am
the whole hammer and punch thing seems, well, primitive and clumsy.

Michael Babinski
Foxfire Jewelers / Things Rich & Strange


#10

Here is an interesting thread on making a hammer handpiece from the
woodcarving handpiece that Harbor Freight sells for $19.99.

https://orchid.ganoksin.com/t/hammer-handpiece

Jamie

PS For those of you who are looking for a cheap ultrasonic with a
heater, I recently purchased Harbor Freight’s $69 2.5-litre model.
It heats and cleans well and is a good alternative for low-volume or
hobbyist work.


#11
swastikas are an ancient Sanskrit symbol/srchetype that
represented one of the Hindu trimurti, Lord Shiva,way before Hitler
usurped it and bastardized its meaning to reflect his yearnings for
world domination and as a symbol of evil... 

Not to forget the Navajo used the symbol to represent the legend of
the whirling log. Mostly in pre-WWII work for obvious reasons…

Rick Copeland
rockymountainwonders.com


#12

Hello Orchidland,

Several have replied, but I have not seen this alternative. An eye
bolt. Available at any hardware store in various sizes, it’s what
the hook latches into on screen doors and such. I recall reading
about this on Orchid some years back.

Polish the eye, put the threaded end in the chuck, and very, very
carefully apply the spinning eye to your bezel. The eye bolt is
better balanced than an allen wrench (or bent nail) and has the
advantage of a “view port” through the center.

Eye protection is critical. Dave Phelps pointed out how important is
keeping things away from the spinning end. I use mine with a flex
shaft - haven’t tried it at the ultra high speed of a Dremel!
(Baaack, baaack!)

Just adding to the tips,
Judy in Kansas