I am wanting to hear from anyone who has used a commercially bought
disc cutter (the punch type). I am a student and have an opportunity
to use a machining workshop as part of my “Tool making” subject, and
I would like to make a disc cutter. The engineer assisting me has
some reservations about how well it would work. Last year a student
made one from two blocks screwed together but there was too much
movement, so I plan to make one out of a single block with a slit cut
in it for the metal (like those in the jewellery catalogues).
Presumably the hole goes right through the block. I was planning on
making the slot 1.2 mm wide to cater for 1 mm metal and thinner. My
tutor’s concern is that for thin metal for metal less than 1 mm, the
metal would buckle and not cut cleanly. Also, presumably the match
between the punch and the hole must be exact. If anyone has any
advice, or has attempted to make one, I would appreciate hearing from
you.
thanking you,
Karin Beaumont
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You might making the entire unit out of piece but divide it into two
but connected with dove tail slides on each side so it will stay
aligned but still be able to be sized down to whatever weight of
metal you are cutting. Also, you will need some sort of exact locking
method which could be as simple as several set screws
Not to be discouraging – but that sounds like a terrible amount of
work to make a tool that’s of limited use anyway. I mean, it only
cuts out circles.
Why not build an hydraulic press – now that would save you some
money. And still be an interesting engineering project.
And you can use it to cut circles plus about a million more things.
To make it challenging, make sure you make the top and bottom steel
plates exactly like the Bonny Doon presses, complete with threaded
holes on the top platen, so you can use all of their accessories.
There must be alignment pins for the halves. The holes need to
ground to a finish not just drilled. The holes in the bottom plate
have to be relieved just back from the upper cutting edge. The
punches need to have the cutting surface at a slight angle rather
than straight across the punch.
Study a book on tool and die making first! The thickness of the
metal to be cut is not really a problem here, it is the overall
quality of the piece. Unless the precision fit is there, the metal
will fold over in to the hole instead of shear off. Just like when
you cut a sheet with dull shears.
Interesting idea. Unless the" engineer" is a practicing machinist, I
would be very leery of this project and his input. If he has not
pointed out what I just did, he doesn’t have a clue. Read a tool and
making book first!
I made an improvised disc cutter a few years ago that worked at
least as well as the commercially made one I use now. The major
difference is that my version will only cut two sizes of disc, 3mm
and 6mm while the other cuts a dozen sizes.
I’d make some observations based on my experience. One- Every now and
then the silver sheet jams solid in the slot as it accumulates burrs.
I clear it by undoing the screws that hold the tool together. It
would be more difficult if the tool was milled from solid.
Two- I get the clearance I need with a shim pinched up by the screws
that hold the tool together. I can change the clearance by changing
the shim.
Three- the punch holes were drilled with new bits so the hole sizes
were reasonably true to label. I was able to use a set of pin punches
which were an acceptable fit.
I know a lot of Orchidians like to make their own tools, but for the
life of me I don’t understand why you would want to waste your time
building something from scratch that is readily available new (and
probably used) and that is perfectly functional. You will never be
able to hand build a disc cutter (unless you have access to a machine
shop and know how to use the tools) that will have anywhere near the
accuracy, durability and functionality of a manufactured one. Spend
your time making jewelry.
Daniel R. Spirer, G.G.
Daniel R. Spirer Jewelers, LLC
1780 Massachusetts Ave.
Cambridge, MA 02140 @Daniel_R_Spirer
Having read all replies and reread your original post, I think I
have some contributions.
The alignment of the holes and the surface finish is the most
important factors. If this isn’t perfect, the punch will stick
and/or break. The cut disc might be deformed on its way out. The
angle of the punch’s cutting edge is also important, more so with
thicker sheet metal. Tempering some or all of the parts doesn’t hurt.
If you look at commercial disc cutters, they rarely are made in one
piece. I have three and they are assembled of at least 3 parts (not
counting the punches). In one of them, the exit opening at the base
is slightly larger than the cutting diameter (size 19-25 mm). All my
punches are tempered.
I also have an assortment of custom made single dies (just one size)
some round, some square and some others but they are without any
alignment. You have to set it in a press with wax (or similar) in
the “cut” stage and then raise the punch, put your metal on the die
and then initiate the cutting. I have a hydralic press and a
swingpress (I believe it is called). I cut metal, leather and PCB.
With enough force (using the hydralic press) I’ve been able to cut
almost 2 mm sheet of silver.
Often I get a sharp edge but that’s easily remedied with steelshot
tumbling or a planishing hammer.
I have made many tools myself and with the aid of an engineering
shop but sofar disc cutter isn’t one because it is not expensive
considering the complex task at hand unless, of course, you make a
production run.
Elaine’s suggestion would be a thing I’d spend time on. It’s a
matter of engineering, machining parts and in the end, save a bundle
compared to buying one.
The disk cutter that I have is bolted together! Make the top and
bottom mate with grooves. That way there is no movement sideways.
I’m assuming you have a Lathe to make the top and bottom? Be sure to
Case Harden the punches and the receivers. My Disc cutter will take
up to 16 gauge metal! It helps to make the bottom of the cutters with
a slight “C” shape. When you make the punches give the tails (the
part you hit) about .001-2 +/- narrower than the heads to keep the
punch from binding. Use at least 1/4" metal or larger for the top and
3/8" for the bottom. Through the middle is a 1/2" - 8 hardness cap
screw. By the way mine is home made.
I am wanting to hear from anyone who has used a commercially
bought disc cutter (the punch type). I am a student and have an
opportunity
Making a disc cutter is an excellent project for a general machinist
apprentice or a tool and die maker apprentice. You will be using
several skills that you will be using lot in the trade. The disc
cutter I made, was constructed out of three pieces of flat stock.
After cutting, I Persian ground the surfaces. I also cut steps for
the third piece to act as a bridge. I then pined all three together
with cap screws and location pins. After rough drilling, I bored the
holes on a mill to tolerance. The last step was to put steps in the
punches before hardening.
Yes you can buy one for a fair price though a tool dealer, but I
will never part with the one I made or the knowledge I learned. Mostly
how to measure accurately. That ability has made me one the best
diamond setter in my area.
Jim Zimmerman
Alpine Custom Jewellers & Repair
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