Sharpening disc cutters

Jewelry Discussion
1

My well used and loved disc cutters are getting dull in spots. Is
there a way to sharpen them? I’ve been tempted to rub them over some
fine sandpaper on a flat surface and see if that helps.

Ideas?

Thanks.
Carla

2 
Is there a way to sharpen them?

Carla, if you have “real” disc cutters, the ones that have punches
that fit into a die block, it will be do-able and worthwhile, maybe.
There’s cheapies that are just punches that aren’t worth buying. The
problem is that you really need to keep the end of the punch square
and straight to the shaft, which means a lathe would be the tool of
choice. Plus they are tool steel, which means using sandpaper and
elbows will be a lot of work - sandpaper runs the risk of actually
dulling the punches by rounding the edges instead of sharpening
them. But yes, if you leave the shaft alone and just take the end
down to a fresh edge that’s of a reasonable precision somehow, no
reason not to. Even an electric drill mounted in a vise and some
sort of toolrest and a stone could do a fair job of it, if done
well.

3 
Is there a way to sharpen them?

Yes the same way they were sharpened the first time, on a tool called
a surface grinder using a punch sharpening jig. Take them to a
machine shop with these tools and it will take only a few moments to
do each one. There is no easy way to do it without this kind of
tooling or a similar rigid, accurate, machine tool. Sand paper will
just dull them by rounding the edges, you need a good hard, loosely
bonded grinding stone to keep from doing this kind of damage and you
cannot hold them by hand with enough accuracy to get a decent edge

James Binnion
@James_Binnion
James Binnion Metal Arts

360-756-6550

4

Normally it is the punch that gets gets at the edges or in some cases
get dinged so you do not get a clean cut disc. Can be resharpened
easily on a Belt Sander… The bottom part of the Disc Cutter’s Block
is not a cutting edge but you can use this to guide & hold the disc
cutting punch square against the sanding belt. (While holding this
side of the block square against the belt push the punch and this
should put a new edge on your punch or clean out the dings on your
edges this should renew your Disc Cutter.

Kenneth Singh
46 Jewelry Supply
karat46

5 
The bottom part of the Disc Cutter's Block is not a cutting edge but
you can use this to guide

Kenneth is correct, but that doesn’t mean the bottom flat is not
important. If you make it convex it will dish your discs and not cut
well or maybe at all, if you make it concave you will lose the
support for your cutting edge, and possibly affect your discs, too.
In tool steel the human thing is going to be to sharpen the edge and
make the center convex, because it is a lot of work. I tried to put
out a way that would be reasonably precise - a drill motor and a
stone and toolrest, but Jim is right. For a good job they must be
precision ground one way or another. I could do it on my lathe with a
toolpost grinder (for myself - don’t want the job…), but sandpaper
will be death for them. You can’t generate a.001" edge with .01"
(or.1") resolution tools - can’t be done.

6

James,

I think if you run the disc punch through the cutting block
backwards (or upside down), you could then use the cutting block to
hold the punch perpendicular to the emery paper or sharpening stone
and thus restore the cutting edge to the punch. You could apply
pressure to the punch with your fingers while reciprocating the
cutting block/ punch(es) together…

This would mean cutting back a little of the cutting block but
should achieve the desired effect, in fact you could sharpen all your
punches at the same time if you wanted to…

John Bowling

7

I have sharpened my circle punch on my Genie diamond wheel. From the
above post, I am sure I can put the punch in the block and push on
the punch with the block on a sheet of sand paper using the block to
keep the bottom of the punch parallel to the sandpaper and sharpen
it.

Richard Hart

8 
I have sharpened my circle punch on my Genie diamond wheel. From
the above post, I am sure I can put the punch in the block and push
on the punch with the block on a sheet of sand paper using the
block to keep the bottom of the punch parallel to the sandpaper and
sharpen it.

The problem with paper or plastic or any other kind of sheet
abrasive is that it is compliant, it will deform slightly with the
pressure you will apply and round the punch edges and you will tend
to dome the punch slightly even when held in the die block. As you
push down on the punch you compress the backing material of the
abrasive and this grinds a rounded edge rather than a flat one. Your
diamond wheel is a different story in that it is not compliant but
without a mechanical aid to hold and rotate the punch you will end up
putting a convex face on the punch which will probably be sharper
than the face you will get from the abrasive paper or film but will
still distort the disc to some degree when it cuts it out. To get as
flat and bur free a disc as possible you really need a mechanical
grinding tool with a means of holding the punch square to the
grinding surface.

It is certainly possible to grind on the face of a punch and drive
it through your sheet stock but for clean flat discs just take it to
a machine shop and pay for a quick sharpening, they will work much
better.

James Binnion
@James_Binnion
James Binnion Metal Arts

360-756-6550

9

Hello, everyone…

Is there a way to sharpen them?

So I would say that there is all kinds of ways to sharpen disc
cutters. After people try stoning,sanding and a lot of other time
consuming tasks they realize it’s not going to work as well as before
and time is money that could be spent elsewhere.Maybe close but not
precise.

You really should consider any tool that needs sharpening be taken to
a machine shop that has a grinder.I don’t mean a bench grinder
either.Have them take 15 or 20 thousandth’s off it and check for a
sharp surface on the tool and demagnatize it. Blades on things like
bench shears can be removed and sharpened too.

I do a lot of “sharpening” here because I have dies to maintain and
the disc cutters we use run by the thousands and require frequent
sharpening to keep the “evil” burs away.

Prices for sharpening shouldn’t be too high.It’s part of what you
haft to calculate into the cost when buying any steel tools or in the
area of tool and die cost’s.

I hear complaint’s about tools.I think that some people expect a tool
to last for ever and work perfectly all the time without any
maintenance or care. I think this, but know every tool requires a
little love sometimes…

Proper alignment will save you a lot of headache. Most disc cutters
can be taken apart for sharpening and sometimes misalign over a
period of usage.You should check alignment frequently. Bench shear
blades usually haft to be shimmed at some point and if you ask the
machine shop to give some shim stock for the difference they removed
on the blade it will save you time.

Have fun!!
Daniel Wade