Sword and large knife sharpening...

[Carter Leffen]

Gentlemen,

I collect swords and various kinds of knives... Can anybody recommend a good sharpening system capable of handling blades from 2" to 40" inches?

Right now I'm using a Spyderco Tri-AngleSharpmaker, using the 40 degree bevel on both swords and knives. My main concern is maintaining a uniform bevel, or as uniform as possible, upon the longer blades...

Also, some blades, especially Khukuris, may have a portion of their blades that are harder than others, requiring more work and care to sharpen those areas...

A friend of mine has recommended a 2" X 36" or 4" X 42" belt sander, with 6" or 8" wheel. I'm leery of hurting the blades's heat treat, or grinding off too much metal...

I appreciate any help and suggestions you may have to offer...

Thanks,

Carter Leffen

 

[RokJok]

I'm leery of hurting the blades's heat treat, or grinding off too much metal...

That's a valid concern. You may want to look into the setups used by knifemakers to make blades in the first place -- a belt grinder, preferably with variable frequency drive (VFD) to achieve slower speeds. The usual size is a 2"x72" belt, although other sizes can work.

There are two issues with going this route:

1. motor type -- For safety, the motor will need to be a type that handles slow speeds and is compatible with the output of the VFD. Check out the warnings and info contained in the VFD technote here: http://www.pge.com/docs/pdfs/biz/power_quality/power_quality_notes/vfd_motors.pdf

2. cost -- These are relatively expensive, especially compared to the price of a set of manual sharpening stones.

A set of Norton commercial water stones can be gotten for well under $200 on this webpage. It's a touch over $100 if you get the 220/1000 and 4000/8000 combination stone pair. Note that the coarser grit stones, especially the 220 grit, wear away pretty fast. So getting a few spares of this grit might be in order. But they are also pretty cheap. A single 8000 grit stone may well last you for your entire lifetime, since they wear away very slowly.

FWIW, professional Japanese sword sharpeners (called sword "polishers") use bench water stones to sharpen by hand even katana-length blades. They simply do one small section of the blade at a time. The polishers I've seen sit on the floor hunched over the stones, which are resting on a low stand/bench/table that is a few inches high. However, to achieve their level of expertise takes many years of practice.

 

[basjoo]

A 1X30 sander is inexpensive and effective. If you use a light touch and move in a quick and controlled manner heat build-up isn't a big issue but it is something to stay aware of. Like any other method, get some old blades and practice a little before doing your good stuff. If you need a high polish to finish with you may have to find another method for that step (though I've heard of good results with leather belts and compound.)

 

[Dave Rishar]

Another vote for the belt sander. Mine is too damned fast to be sharpening with (around 3000 rpm or so) but I use fine grits, a light touch, and fast movements to get 'er done, plus frequent dunking in a bucket of water. It takes a little practice to get good at it but I believe the results are worth it.

The biggest thing to watch is the tip. If spend more than a moment there, or aren't frequently dunking in water, it will burn. (Been there, done that.) Not a big deal, really, but avoidable with care.

The technique for doing differentially hardened blades must be felt to be learned, as the hardened zone will give a noticably different feedback than the less hardened areas and it can throw your angle off if you're not careful.

 

[Doug C]

EdgePro.Lyle informed me that any size you can hold on to can be sharpened uniformly.I have sharpened a 16" blade on my EdgePro and see know reason a 40" blade couldn't be sharpened as sharp as you want.Almost infinitely adjustable. Been here long enough to know belt sanders are a great way to sharpen just don't have one and the EdgePro does everything I need for now.And a strop.

 

[Kohai999]

FWIW, professional Japanese sword sharpeners (called sword "polishers") use bench water stones to sharpen by hand even katana-length blades. They simply do one small section of the blade at a time. The polishers I've seen sit on the floor hunched over the stones, which are resting on a low stand/bench/table that is a few inches high. However, to achieve their level of expertise takes many years of practice.

It depends upon what kind of swords and what level you are talking about.

It is very difficult to sharpen Japanese and Chinese traditional swords in the above mentioned manners.

Why? Well like was said, the Japanese sword polishers are polishing the blade to a zero edge, same with Chinese swords. There is no secondary bevel.

If you are talking low value swords, or European swords, use a belt grinder. If you are talking good Chinese or Japanese swords, you can use a pocket diamond hone in "fine" grade, and lightly work up and edge section by section. For any sword that costs you over $2,000, go to a professional.

Best Regards,

STeven Garsson

 

[Cliff Stamp]

It is very difficult to sharpen Japanese and Chinese traditional swords in the above mentioned manners.

Why? Well like was said, the Japanese sword polishers are polishing the blade to a zero edge, same with Chinese swords. There is no secondary bevel.

This doesn't make it hard to sharpen on a belt grinder, in fact single bevel convex grinds are the easiest that way, just work in the slack region and adjust force to get the required curvature.

-Cliff

 

[nedocervar]

I strongly suggest reading "The Craft of the Japanese Sword" - Leon and Hiroko Kapp with Yoshindo Hoshihara - , supply by "The Japan Woodworker" (www.japanwoodworker.com). In that very interesting book there is chapter entirely dedicated to sword polishing by Okisato Fujishiro.
-Nedo Cervar