Grinding on a 2" and 4" wheel?

theWeatherman

theWeatherman

Well-Known Member
So I had this idea to take the wheels on my 2x42 craftsman and switch them out to rubber covered contact wheels, I haven't measured them but I am sure they are 2" and then 4". I then thought that I could then use those wheels to grind on. Now I started doing searches on grinding wheels and hollow grinds and find that most people use 8-12" wheels to do their grinds. I even find a grind height calculator for the wheels and thickness of the stock used.

I was hoping you guys could tell me about grinding on the different diameter wheels and why you need a grind height calculator? Why cant' you just use the wheel like a platen and walk the grind up the blade towards the spine (which is what I do for flat grinds)?

Thanks!
Brian
 
When you walk the grind up the blade with a wheel you can get an uneven surface, like a wash board. These may be very slight an undetectable by eye, but when you go to progressively finer grits you will miss scratches in the low areas. It's one of the problems I'm discovering in my quest for a mirror polish.

Holding the wheel to the blade with no walk gives a consistent even surface.

Hope this is helpful
 
2012_0424Knife0002.jpg

Each of these knives has a varying degree of walk in the grind. The top and bottom more so than the middle. These are all 8" wheel grinds. There is a lot more to this than can be explained briefly and I'm sure everyone will have their own technique. Anyway, this works for me but took a lot of time to perfect.......After walking the grind to it's approximate upper limit, I'll start taking light passes with 380 grit while constantly "wiggleing the blade from top of the grind to the edge. This blends the humps and bumps well enough for heat treat. After HT I do the wiggle routine with a medium scotch brite, fine and x-tra fine. You must be careful, this does wash out grind lines like on the top knife at the ricasso/bevel line. The scotch brites are essential (for me) for blending the radius. After all this hoopla, I refine the grind with high grit belts with very light pressure depending on level of finish you want. Top/600 grit /etch
Middle/ 600 grit/ etch
Bottom/mirror/ blued

I do this free hand, I don't think a jig will afford you the level of control required. Also, you may get some success with the 4" wheel, but the 2" wheel won't afford you enough surface area for control. I don't use a calculator but I do start with a plan and drawing. After this long winded diatribe.....I also have the advantage of wheels from 4" to 12" now, makes life much easier, I can refine the grind with the next size wheel . Hope this helps. Practice, practice , practice. Click on the link below for differing wheel grinds.

Good luck,
Rudy
 
Great info Rudy, when you say wiggle ?

Lets say you are holding the blade edge up against the wheel by the handle in your right hand.

Would the wiggle be a vertical movement up and down? In effect the contact area of the, wheel to blade, being at a diagonal?

Hope that makes sense.

Love those stacked leather handled knives.
 
Bill Luckett only uses a 3" wheel on his knives. He grinds and then tilts the wheel at a 90 angle and continuse the grind. have yet to see him grind like this but talked to him for over 2 hours about it. I tried it but ground through the blade trying to do it. check them out here
http://www.billluckettcustomknives.com/
 
Mark Behnke said:
Great info Rudy, when you say wiggle ?

Lets say you are holding the blade edge up against the wheel by the handle in your right hand.

Would the wiggle be a vertical movement up and down? In effect the contact area of the, wheel to blade, being at a diagonal?

Hope that makes sense.

Love those stacked leather handled knives.
Click to expand...

Mark,
The motion is more twisting top to botton of the grind while still pulling it horizontally across the wheel. Just like using a signaling mirror quickly or turning a key back and forth. If you use any vertical motion, you'll put a flat spot in that area unless it's a sweeping motion. It takes some practice, especially on your weak side, my left. The easiest way is using the 10" wheel after HT to clean up the 8" grind. No scotchbrites involved in that procedure. Thanks for the compliment.

Rudy
 
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I've been studying his grinds since the 80's.....beautiful work.

I'm sure it can be done even a 2".....but not by me. lol.
I've tried several things over the years on 2" wheels and keep sliding up over the wheel wrecking my grind. There doesn't seem to be enough surface area to keep the wheel in the groove. I must say I've never tried it on a rubber 2" wheel though, this may be a reason for the problems.

Rudy
 
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I've made a few small daggers on my two inch contact wheel.
To answer one of your questions? The bigger the wheel the bigger the radius in the grind.

The 2" wheel worked for a dagger or thrusting weapon, but would make a terrible Chef knife.

The origin of hollow grinding came from water powered wheels that were up to several feet across.
the knife makers would lye on a rafter above the wheels with their arms dangling and grind against them.

Laurence

www.rhinoknives.com
 
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