Strap punch sharpening

[HondoMan]

Right then, I recently upgraded my strap end punches.  Blanchard.  While I do like Blanchard tools and own quite a few, these were expensive and have taken time to order.  Dull, would be an overstatement.  I doubt the punches would cut through wet dough!  I made the mistake of asking a mate who owns a knife making business to see if they would be able to put an edge on one of the rounded punches.  The edge of that punch, while sharp(er), is jagged and rubbish.

I have looked under 'Sharpen it' and scoured the Internet for a video.  Nothing.

How does one sharpen a rounded punch?  Along the edge or pulling?  Twisting or turning along the edge?  I don't wish to destroy the edge of these as they were no on the cheap.

Cheers!

[chuck123wapati]

2 hours ago, HondoMan said:

Right then, I recently upgraded my strap end punches.  Blanchard.  While I do like Blanchard tools and own quite a few, these were expensive and have taken time to order.  Dull, would be an overstatement.  I doubt the punches would cut through wet dough!  I made the mistake of asking a mate who owns a knife making business to see if they would be able to put an edge on one of the rounded punches.  The edge of that punch, while sharp(er), is jagged and rubbish.

I have looked under 'Sharpen it' and scoured the Internet for a video.  Nothing.

How does one sharpen a rounded punch?  Along the edge or pulling?  Twisting or turning along the edge?  I don't wish to destroy the edge of these as they were no on the cheap.

Cheers!

first off a punch doesn't have to be razor sharp or soon after you hit it with a maul a few times the edge will roll and be useless. if you can see any amount of flat on the edge then it needs that taken down to non existent but not thinned or sharpened as you know sharp to be on a knife. I use a very fine sanding belt 400/600 grit on my belt sander so not much metal comes off and slowly turn the punch until i take down that flat edge keeping the wide bevel intact. what ever method slow is the key and paying attention to removing only enough metal to eliminate that flat area.  I'm sure you can do it many other ways but thats the tool i have that works best. the idea is to end up with a good stout edge that tapers to zero and is still even all the way around and is strong enough to smack with a hammer. 

good luck!! 

[sbrownn]

https://www.rmleathersupply.com/collections/rocky-mountain-tools/products/rocky-mountain-round-hole-punch-sharpener

I've never used one of these but it has decent reviews.

[bruce johnson]

I’m going to put out another perspective. There are old wood handle strap end punches designed to only be used by hand, simply rocked back and slice the end of the strap. Those need to be sharp. I sharpen my personal  all metal strap ends to this same level of sharpness. I can pretty much drive any punch other than a rosette punch with a 1 pound maul. Easy punching is more fun for me. 
     The punching surface is important. I recommend LOW density poly for punching, followed by either end grain wood or sole material. You want the punch to cleanly punch through and slightly into the material. These material allow that without deforming the punch edge.  You need a good supporting surface under the punch material - i used an anvil or a granite headstone depending on which end of the shop I was at.

     I sharpen the outside edge and am a little spoiled. I’ve got a 2x72 belt grinder, 1x42 belt sharpener, and round platen grinder now to sharpen on. I go at least to 1200 grit. Once I have the edge I run a tapered Diamond rod sharpener to take off the inside bur.  I buff with black and then green compound on the lower speed end of a variable speed grinder or a shaped leather strop wheel in my drill press to polish the edges. This can all be done by hand too, just takes time. 
I’ve attached a short clip of a punch I sharpened a few years ago. It is test cutting some scrap skirting on my workshop bench. Pre tripod era so one hand was holding the phone and one hand on the punch, not a quality video but you get the idea. . 

[TomE]

I used an Arkansas oil stone to shape and sharpen a 3/4" English point punch last night.  Mainly pushing strokes on a medium and fine stone, then stropped using green compound.  Took over an hour but I wanted to go slow and keep the cutting edge flat.  The luxury of being a hobbyist.  I am using the punch to cut a taper on a strap and its much improved.  The dull punch was drifting towards the edge of the strap instead of punching straight down.

[Hardrada]

These are used on wood, but it's still steel and it's still round, so, it may help:

 

[HondoMan]

On 11/7/2022 at 12:44 PM, chuck123wapati said:

first off a punch doesn't have to be razor sharp or soon after you hit it with a maul a few times the edge will roll and be useless. if you can see any amount of flat on the edge then it needs that taken down to non existent but not thinned or sharpened as you know sharp to be on a knife. I use a very fine sanding belt 400/600 grit on my belt sander so not much metal comes off and slowly turn the punch until i take down that flat edge keeping the wide bevel intact. what ever method slow is the key and paying attention to removing only enough metal to eliminate that flat area.  I'm sure you can do it many other ways but thats the tool i have that works best. the idea is to end up with a good stout edge that tapers to zero and is still even all the way around and is strong enough to smack with a hammer. 

good luck!! 

I think, perhaps, I have a solution.  I've been purchasing wet-dry paper from a guitar shop for my awls.  These are between 500 and 12000 grit.  Seems they sell various lengths!  I have a bench grinder with a sanding drum on which I can attach various grit paper.  I just ordered some for the drum, so I'll see how I get on.

Cheers!

[johnnydb]

Just pay attention to the edge geometry and the temperature of the tool while doing your grinding.   

If you change the angle of the edge the performance will suffer.   

If the tool gets too hot you can lose its temper and again the tool will dull too quickly.  So keep a cup of water handy to dip it in regularly.   

[chuck123wapati]

5 hours ago, HondoMan said:

I think, perhaps, I have a solution.  I've been purchasing wet-dry paper from a guitar shop for my awls.  These are between 500 and 12000 grit.  Seems they sell various lengths!  I have a bench grinder with a sanding drum on which I can attach various grit paper.  I just ordered some for the drum, so I'll see how I get on.

Cheers!

that should work perfectly. good luck!

[Danne]

This is probably not suitable for your purpose where you completely lack a cutting edge, but maybe could be a good solution to sharpen hole punches?

https://crimsonhides.com/products/hole-punch-sharpener