Modifying Blade Shapes on Traditional Knives

[Archie]

I see examples here of blades on traditionals that have been modified...spears made into clips, various secondaries made into wharncliffe or coping, etc. For those of y’all doing this kind of work, what tools and process are you using? I assume folks are using some sort of coarse material removal followed by some sort of smoothing or polishing to match original finishes. Is this strictly hand tools? Power tools taking care not affect heat treat?

 

[Trout Hound]

I believe most use a belt sander. As mentioned, the blade must be dipped in water frequently to avoid ruining the temper. Depending on hardness, you can sometimes do minor reprofiling with a file, but patience is a virtue when working with hardened steel, and you will wear out the file pretty quickly. A diamond file or honing stone can make things go a bit faster.

 

[solphilos]

Belt sander and/or rotary tool. The work can be done with files followed by various grits of sandpaper as well, though it can be a lot of work for some modifications.

 

[Obsessed with Edges]

This was a relatively simple blade profile mod, as they go. But here's a description of what I did with my Buck 301's spey. If you're familiar with Buck's current 301 stockman, you're aware it's spey is sort of odd, in that the tip of the spey sits above the liners when the blade is closed. I didn't much care for the look of it, and wanted something looking more properly nested in the handle. To do this, I had to grind down the spine to a tip that sits just far enough within the handle; in doing so, it naturally took on the appearance of a spear blade, instead of the blunter-looking spey profile. I don't have a grinder, so I improvised something by manual means and it worked out pretty well. I've used essentially the same means to repair/re-point severely rounded or blunted tips on other old knives. The text and pics below are what I'd posted in an older thread along the same subject lines, so I just cut & pasted it here for simplicity's sake:

I reshaped my Buck 301's spey to more of a pen/spear profile. I used a 120-grit 3" x 21" zirconia-alumina sanding belt cut and glued flat to a 24" board. Drag the spine in a tip-trailing stroke along the length of the belt, starting relatively low-angle and gently raising the handle through the stroke to facilitate the curvature toward the tip; don't raise it too much. I used a wine cork stuck sideways onto the sharpened edge of the blade as a place to rest my index finger and exert pressure downward into the abrasive; that makes a pretty big difference in grinding speed, done with a little pressure. The 4th pic below shows some additional thinning, convexing & polishing of the edge, at some later time.

 

[WhittlinAway]

I’ve done all mine with files. I mostly work on small blades, and don’t do that many of them, so the extra time involved isn’t a concern for me.

If you want to give files a try, I got some great advice when I asked in this thread a while back.

 

[deltaboy]

I use sand paper and coarse sharping stone.

 

[Blue Sky]

I’ve modified several knives, some a little, some a lot. Always used files since I don’t have a belt sander, but never really felt it was much of a handicap. It forces me to go slower and I feel less likely to wreck something. Not everything needs to be done fast to be good.

Cover one side with masking or painters tape and sketch out what what you want. Then cut carefully along the line and remove the tape on the waste side. Then just file down to the tape. After that, sandpaper to clean things up. Use a progression of finer grit levels, say 300 through 800, or even 1500, depending on how polished you want it.

 

[black mamba]

I do the rough work with a 60 grit belt on my 1x30 sander. Then progressively finer grits hand sanding from 100-400, followed by a buffing wheel with white rouge.

 

[knarfeng]

I modified the title to emphasize this is just about modifying traditional knives.
(got tired of moving posts to General)

 

[Ernie1980]

I use a belt sander like most of us here to do the majority of the work, but then use sandpaper to smooth the edges and match the blade's finish. On some vintage knives with a patina already formed, I then will use fruit or somthing similar to patina the newly cut area to the rest of the blade.
Here is one I did recently, the two blades that are straight out both stood proud and I re-shaped them slightly.

Here is a Case where I turned the Spey turned into a spear:

So what do you have in mind??

 

[Archie]

If you want to give files a try, I got some great advice when I asked in this thread a while back.

Thanks for the reference. Your thread had exactly the kind basic information I needed. If this was a power tools only thing, I was probably out. For hand tools, I really didn't know where to start with files. For a one off project, I can be patient and take my time. Now to see if I can really follow through with what I have in mind.

 

[traumkommode]

Harbor Freight 1x30" belt sander. I've used it to do profile reshapes, i.e. spey to spear and spasp to sheepsfoot; cut sharpening notches; reshape handles; and even regrind (thin out) blades.

Use a sharpie to color the material you want to remove, then just pull that part of the blade across the belt, do the blade in a glass of ice water, and repeat until you have the shape you want. Then I alligator or c clamp the knife to a table and use sandpaper to finish the edges. Dremel with a cotton wheel and flitz to polish.

 

[SVTFreak]

The only one I’ve done, I used a bench grinder. Turned a spey into a penish shape. I have a course and fine wheel on my grinder. Got close with one. Touched up on the fine then I resharpened it. It ain’t perfect but it sure is perfect for me!

I made a quick swipe on the wheel then it went for a good swim. Rinse and repeat until it was where I wanted it.

 

[Will Power]

I need to get some power tools I've only modded small blades on carbon or 420 type stainless, usually Spey to Pen type of thing. Always suspected power tools could compromise the heat treat/temper-especially on little blades but now it seems I'm wrong. I've used files or diamond rods and a vice, then use a Shaprmaker rod and paper to polish it down plus strop with green compound.

Very interesting thread this, thanks to all for worthwhile pictures and tips and thanks to Frank for changing the title and not moving it to the General

Lot of people show mods here,either due to wear, busted tips or desire for a new shape. I remember Jeff (Black Mamba) did a particularly cool and ambitious mod on a CASE Bonestag Saddlehorn I sold him turning a lanky Skinner secondary blade into a Sheepfoot type, very good result too.

Thanks, Will

 

[r8shell]

I have a Ken-Onion-Work-Sharp machine, which is basically a tiny (12"), variable-speed belt-sander. It's sufficient for small traditional blades. I don't worry so much about the heat-treat when I'm taking material from the spine of the blade. I go slow, and finish by hand.


On this one, I used a friend's grinder to remove the bulk of metal, and finished on the Worksharp and sharpening stones:

 

[traumkommode]

I have a Ken-Onion-Work-Sharp machine, which is basically a tiny (12"), variable-speed belt-sander. It's sufficient for small traditional blades. I don't worry so much about the heat-treat when I'm taking material from the spine of the blade. I go slow, and finish by hand.
View attachment 838175
View attachment 838176

A word on the heat treat - there is a saying that, "if it's too hot to touch, it ruins the temper." I think that's somewhat incorrect, as knifemakers grind heat treated blades all the time, and when you watch them working, there is no ice water dip. They just wear gloves. Tempering temperatures are usually around 450 degrees or 500, and a blade becomes too hot to touch around, what, 130 degrees? Discoloration (rainbowing) is what to watch for, and I've only ever seen it happen when I've been regrinding (thinning) an edge to an incredibly thin dimension and there wasn't much metal left at the tip. Making sure to use good quality fresh belts is a good idea, because worn belts will create friction and cause heat without removing much metal.

 

[black mamba]

Nicely done, r8shell. Here is the mod to the saddlehorn Will referred to above.

New

Modified

 

[r8shell]

Nicely done, r8shell. Here is the mod to the saddlehorn Will referred to above.

New

Modified

Wow, I love it! I see the Saddlehorn in a whole new light!

 

[black mamba]

Thanks! Now it's a nice pattern to carry and use.

 

[Blue Sky]

My latest, an Opinel 12 before and after. Didn’t remove a lot of material, so it didn’t take long even with a file. Just needs some stain now.

t