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Grizzly grinder - Search "G1015" - This is the baseline 2" x 72" entry level machine. It will need some work to the platen and it is difficult (but not impossible) to do hollow grinds with the stock 8" wheel because of motor clearance issues. If interested, WAIT FOR IT TO GO ON SALE. This happens about twice a year and is a much better deal. (see Modifications for the Grizzly G1015 grinder for improvements or "Tracking the Grizzly" to resolve tracking issues)

Ovation belt grinder - Japanese page; Translator (cut and paste the url; use the lower set of characters in the url drop down box for English)

Some thoughts on grinders (as found on various knife related forums):
This is Ed Caffery's response to the question "... would one of those little Delta 1x42 belt/disc grinders get me by for the first year or should I go ahead a buy something like a multitool? ": " The cheap part of me says that the 1x42" grinder will work, but the other side wants to tell you that if you can spring for a good 2x72" grinder, you'll never have to buy another one, and your learning curve will be cut considerably.
I still own that first Wilton Square wheel grinder that I purchased from Koval Knives....at that time it cost me $540 with shipping, brand new (guess it has been a while ). I've gone through a few contact wheels, and a few bearings, but she works as well today, as she did out of the box.

I think doing it by hand a few times will render benefits too. Remember, the machines won't do anything that you can't do by hand....all they do is save time. If I remember correctly, the first dozen or so knives I made were forged and finished all by hand."

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Craig Wilkins on the advantages/disadvantages of 2 and 3 wheel machines:

"I have noticed that some belt grinders have just 2 wheels while others have 3. What is the advantage of one over the other?

I will try to answer this one...

As stated, there are basically two types of grinders alluded to above, basically the Burr King and Hard Core grinders are of the two wheel variety, Rob Frinks's excellent KMG grinder and the Bader grinder are of the the "three wheel" variety.

I have used at different times a Burr King, Wilton, Bader and a Hard Core, I own a variable speed Hard Core grinder but to be fair and truthful about it, I bought it before I ever used any of the others. The Burr King was/is not available but is an excellent machine.

Two wheel setup - Burr King and Hard Core

Advantages:

Tracking is unsurpassed, smoothest machines on the market that I have used. Just a dream to use.

Disadvantages:

1) Attachment setup takes a very long time. Five to ten minutes if changing from the flat platen assy. to a hollow ground set up. (I may add that the flat platen assy. makes this in essence a three wheel set up) I have a 10 inch contact wheel. When going from it to the flat platen assy., the idler wheel had to be swapped out as well. The flat platen assy. requires an 8 inch idler, the 10 contact wheel requires a 6 inch idler. (Maybe THAT'S why I don't hollow grind very often!)

2) The belt on these type grinders are driven off of the contact wheel. When changing contact wheels (4 inch for flat platen assy., 8 or 10 inch or whatever for hollow grinding) the belt speed changes. For example, the belt is A LOT slower for flat grinding. Let's just say that the MAXIMUM speed is slower with a variable speed grinder when changing to a smaller contact wheel. How is this important? Slower speed equals slower grinding.

Three wheel grinders - KMG and Bader

Advantages:
1) Setup and assy. change out is a breeze, takes about 10 seconds max. (The flat platen assy. makes this a 4 wheel grinder in essence.)
2) Belt speed is constant - regardless of the assy. installed, it is driven off of the same drive wheel.

Disadvantages:
1) Does not track as well as a two wheel set up. Not as smooth.

From a personal perspective, if I were to buy another grinder after using some of the others, it would either be a KMG or another Hard Core. With the Hard Core, I would leave it set up in one set up only. This is the primary reason why I have a separate small wheel setup opposed to having the small wheel assy. that Hard Core has to offer.

One thing that I have found. I am spoiled with variable speed. To anyone that is in the market for a quality grinder, variable speed is worth every penny! From final finish to sharpening.

Now, after stating all of that, a friend of mine made his own grinder using a motor, round stock for the shaft, an idler assy he bought from one of the knife supply houses, pillow block bearings and a 10" Burr King contact wheel and is just as smooth as the Hard Core grinder I have. He spent less than $500 on it. Other than it not being variable speed, it is one of the finest setups I have ever seen. Granted, he can't change set ups but it is as smooth as silk!"

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Ed Caffery posted this on contact wheel durometer: "70 durometer is the standard that you will see on most commercially available contact wheels. It's what comes as standard equipment on all the usual grinders you see in a knifemaker's shop. (Bader, Burr-King, Square Wheel, etc.)

Contact wheels are a double edge sword.... too soft and it's easy to "wash out" your grind lines, and the wheel edges will become rounded in very short order. Too hard and the wheel leaves a terrible finish (both referring to smooth wheels) With serrated wheels, a softer wheel will remove stock faster, but will wear down quickly, a harder durometer serrated wheel will take material off about like a softer smooth wheel, but will last much longer and take much more abuse.

Generally the 70 durometer is about normal for most knifemakers. Top end you can achieve with most rubber compounds is 90 durometer. The rounding of corners isn't a big deal because most of us will put a slight radius on the wheel edges right out of the box.

I agree with Don, stay around 70 durometer max. and you'll be good all the way around."

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Gene Osborne on contact wheels: " Contact wheels are like tires on a car. Most people won't know the difference but a "driver" will.
Wheels first have to be balanced. The faster they go, the more critical this becomes. Unstable wheels WILL come apart.
Bearings or pillow blocks are needed if not mounted directly to the shaft. Plastic is not a good choice especially for fast machines.
The face must be smooth and round. This can be trued once on the machine. If it is not round, it will dig pits and ruts, bounce, and give poor grinds.
Hard face has no rubber.
Smooth face for finish grinding.
Serrated wheels for hogging metal.
Diameter controls the geometry of a hollow grind, most use large diameter wheels to give a flatter appearance. I use a 6" wheel for most hollow grinding because it gives a more dramatic hollow grind.
Lawn mower wheels are not recommended.
Casters can work, the best ones are from the medical world.
Most Americans don't mind driving on cheap tires, but the pro's want/need the best.
If your grinder does 80% of your work for you, why skimp there?"

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Bob Warner on variable speed:
"When you are working your way down the list of grits during your knifemaking, you will get down to the 400-600 grit range (and then even finer). At this fine grit there are a couple of potential problems, first your metal can get real hot real fast. If you are cleaning up a hardened blade, you can ruin the heat treat and have to start over. Also, at a slow speed, your errors are not exaggerated. If you accidentally make a mistake, it will be less of a mistake if the belt was running slow (I know all about making mistakes, I must be an expert at it)."

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Ed Caffery on grinding belts and backing materials: "This is a response to a question from another thread. I thought it might be of interest to many folks, so I started a new thread with it in order to make it easy to locate.
Please add your inputs and experiences, these are my personal finding and experience, and I'd be very interested to hear from others.

Different backings make a belt stiff or flexible, depending on the type of backing, and I have found that the backing material makes a big difference in the finish you get out of a particular grit size.
For example, a "Y" weight backing is generally the thickest, stiffest backing, and you find it mostly on the heavy grit belts (60 grit and larger) "Y" weight belts don't like to bend around tight radius areas such as small contact wheels. I have watched (and felt) the grit tearing off of "Y" weight belts on contact wheels of 3" diameter or less. On several occasions I have had brand new "Y" weight belts break on startup when trying to use them on small contact wheels because the backing doesn't want to flex around the wheel, and the joint just wouldn't take the stress. This weight backing is generally found on heavy grit belts of 24-60 grit.
"X" weight is a bit lighter and more flexible, and is generally what I like to use for my heaviest grit belts. It can make the bends around contact wheels as small as 3/4" diameter without much trouble. I've seen "X" weight backing on belts as fine as 400 grit, but don't like it in anything finer than 120 grit.

"J" weight is next in line, sometimes referred to as "J-Flex" backing, it is a light weight backing that is very flexible. I like to use it on my finer grit belts because I can track the belt out past the edge of the platen, and radius out plunge cuts with it. (the backing will make a nice fine radius when it wraps around the edge of the platen.)

"Mylar" backing is found on the 3M micron belts. It is a "plastic" material that is very thin and light. It will easily flex around the smallest diameter contact wheels, but does not flex well the other direction (like around the edges of platens or contact wheels) If you ever use this type of belt, be VERY careful about getting your hands close to the edges of the belt. It will cut you like a razor blade never even thought about! I've had more than one trip to the ER to get sewn up from these belts.

I've been using Norton Norax belts for the past couple of years in X30, X22, & X16 (400, 800 & 1200 grit) and really like the backing on these belts. I'm not sure what to call their backing material....it's thickness seems to be somewhere between an "X" and "J" weight, but is is much softer than either, and very flexible. These belts seem to give a finish that is finer than the same grits in other belts, and are so flexible that you can do just about anything with them and they hold
together."