Any Way To Sharpen Round Punches?

[emr454]

I found an old C.S. Osborne No.13 round punch in my grandfather's toolbox. It isnt very sharp anymore and you can tell it was used with a metal hammer for years. I tried to cut a hole in some 6 ounce leather but I don't have a heavy mallet, so maybe that is the problem?

Is there any good way to sharpen or touch up the edges of a round punch like this?

Eric

Edited January 9, 2011 by emr454

[Art]

Hi Eric,

For Osborne "arch" punches (most of what I have), I center them up in the lathe and sharpen them up with a hand stone or stones if really bad. I catch the insides (remove the burr) with a sharpening stick which is just an round oilstone on a stick. For non concentric types like yours, I just use and oilstone around the outside edge by hand and again use a round stone for the inside. CSO makes a little conical stone that is good for the insides.

Art

I found an old C.S. Osborne No.13 round punch in my grandfather's toolbox. It isnt very sharp anymore and you can tell it was used with a metal hammer for years. I tried to cut a hole in some 6 ounce leather but I don't have a heavy mallet, so maybe that is the problem?

Is there any good way to sharpen or touch up the edges of a round punch like this?

Eric

[emr454]

I have a few conical stones that fit in the Dremel, could I use those by hand for the inside?

Eric

[BIGGUNDOCTOR]

Hold off on the power tools, you can easily go from an easy touch up to a whole reworking of the cutting edge with one slip.

Dressing the inside is just to remove any burrs, no real stock removal.

Punches generally are not that hard, so I would dress any bad spots with a good file, then touch it up with a stone, or two. The shank can be dressed on a bench grinder to remove all of those potential eye poppers. The top should have a chamfer around the edge, with a slight crown.

When you use it make sure that you have an appropriate surface under the punch; poundo board, plastic cutting board, lead block, or what I use, a block of end grain wood. Don't punch across the grain, always use end grain. This will give you easy, and clean cuts.

Edited January 9, 2011 by BIGGUNDOCTOR

[emr454]

Hold off on the power tools, you can easily go from an easy touch up to a whole reworking of the cutting edge with one slip.

Punches generally are not that hard, so I would dress any bad spots with a good file, then touch it up with a stone, or two. The shank can be dressed on a bench grinder to remove all of those potential eye poppers. The top should have a chamfer around the edge, with a slight crown.

When you use it make sure that you have an appropriate surface under the punch; poundo board, plastic cutting board, lead block, or what I use, a block of end grain wood. Don't punch across the grain, always use end grain. This will give you easy, and clean cuts.

I planned on just using the stone from the Dremel kit, by hand. I didnt want to ruin the punch so I had no intentions of using the Dremel itself.

Eric

[emr454]

Well, it seems I just needed to use a properly weighted mallet and the end of a 4x4. Took about 4 whacks to punch through 2 layers of 6/7 oz. leather.

Thank you for the help and suggestions!

Eric

[FatSmitty]

If you have access to a grinder, I would dress the shank end as previously suggested. Just grind the "mushroomed" pieces back flat with the shank and then put a 45 degree angle around the drive end sorta like this \___/ . Impact tools can be very dangerous when in that condition. Chips can fly off and are just like shrapenal, let alone they can slice your hands when handling them. When I worked Maintenance of Way department at the railroad, a welding crew used a drift punch with a mushroomed drive end and it "threw" a chip and cut a guys neck and into his jugular. He survived, due to his work crews quick thinking and action, but that could have been a fatal accident. One of the chips could easily take out an eye also. This could be accomplished with a hand file also, would just take some time and elbow grease. I just don't want to see someone be needlessly injured is all.

[BIGGUNDOCTOR]

Probably a LOT faster to just hacksaw the mushroom off since it is so huge. Ya need to protect yer peepers since the fake ones don't work as good as the ones you have.

[emr454]

I'll be taking care of that today. Probably be just as easy to chuck it in a vise and use the 4" angle grinder to smooth it out.

Eric