Knifemakers Abrasive Belt Buyers Guide

The world of abrasive belts is a confusing place for even the most seasoned professional. In this guide we will try and describe what belt to use for what application and why.

Rough Grinding Steels and Stainless Steels

Often we hear abrasive belts described as “Sanding Belts”. The reality is knifemaking has progressed a long way since the use of stones and abrasive wheels!

We don’t sand steels on sanders or even linishers, we grind steel on grinders. We can remove steel faster than ever would have been possible in history.

To grind steel, we use ceramic belts 36 through to 120 Grits.

Here are a few things you need to know about ceramic belts!

1. They need to run fast and hard to get best performance:

   The ceramic grain will start to glaze and go blunt as you grind, when you grind with maximum speed and pressure the ceramic grains start to break down exposing fresh sharp edges and you will get a corresponding longer cutting life from the belt. Ceramic belts are probably a waste of money on some grinders that have neither the speed nor power and the belts will glaze and go blunt very quickly.

2. They don’t cut well in fine grits:

   Think about this, if we lie down on one nail it sticks right into us. But lie down on a bed of nails and the weight is distributed over so many points that none of them have enough force to penetrate. If we have only a few grains per square centimeter on a ceramic belt (36-120 grit) the pressure on each grit is much greater during the grinding process, and as per point one, the grain will break down exposing fresh edges and keep cutting, below 120 grit and the harder grain works against you. None of the grains are getting enough pressure to break down and the result is glazing and very blunt belts very quickly

3. They work best on heavy polyester backing.

   Heavy polyester backing allows optimum pressure between the material being ground and the belt.

4. Grit Progression

   A normal progression in grit in knifemaking is 50 or 60 grit for rough grinding, then 100 or 120 grit for final grind. Normally people who forge blades like to use an aggressive 36 grit belt to remove hammer marks and some people prefer to start with a 60 grit belt.

5. Soft Materials

   As amazing as good quality ceramic belts are, they are not at all recommended for soft material. They glaze and clog up, quickly ruining an expensive belt.

 

Manufacturers Number: Click to go to the product page and buy	Colour	Manufacturer	Grain Type	Backing	Suitable for:	Notes
R980 “Blaze”	Orange	Norton	Ceramic	Stiff	High Pressure Grinding	The premium belts for knifemaking applications. These belts cut better and outlast everything else in their class. Available in grits between 50 and 120. Click Here To Buy
CN466Z	Green	Hermes	Ceramic	Stiff	High Pressure grinding of steel and hardened steel. This belt loves rough grinding.	These are the premium grinding belt from Hermes, described by Chris Williams of Wilmont grinders as “two thirds as good as Norton Blaze, but at 1/2 the price.” These have not been available in Australia for some time but have been released again by popular demand. Currently only in 50 Grit, we recommend you try this belt. It needs fast speeds for maximum life and performance. Click Here To Buy
CR456Z	Green	Hermes	Ceramic	Stiff	Flat Grinding metals	These belts are used for all general purpose metal grinding applications Click Here To Buy

Grinding Even Radiused Plunge Lines.

Grinding even plunge lines is one of the most difficult thing for the beginner to do well. It is also one of the first things a buyer will likely check on your knives.

To grind nicely radiused plunge lines there are two common methods:

1. Using J Flex belts. J Flex Belts are about as flexible as abrasive belts get, starting with a 120 grit belt tracked about 3-5mm over the edge of the platen, the plunge line is ground on one side of the knife, If free hand grinding, normally the first grind is done on the off hand. The belt is then tracked over the other side of the platen and the other side of the knife is ground by eye to match. This method requires only a few dollars worth of belts but takes some practice. It is not uncommon to radius the platen for a better result, but with practice this is not necessary.
2. Clamp the knife in a file guide and grind up the guide with the radiused edge of a Trizact Gator belt. Trizact Gators have an exceptionally deep coating of structured abrasive. Abrasive that has been laid down precisely on the backing. This can allow the user to grind up to the guide and leave a nice finish, even on both sides.

Manufacturers Number: Click to go to the product page and buy	Colour	Manufacturer	Grain Type	Backing	Suitable for:	Notes
CR456J	Green	Hermes	Ceramic	J-Flex, Super Flexible	Curves and radiuses in hard materials	Great for work finishing stainless guards and grinding convex shapes. A great use of this belt is grinding perfect curved plunge lines by tracking over a radius edged platen. Click Here To Buy
RB406J	Blue	Hermes	Aluminium Oxide	J-Flex, Super Flexible	Finishing curved surfaces in timber and soft metals	The Aluminium oxide grit works better for softer materials, the CR456J would be a better choice for steel Click Here To Buy
LS312JF	Yellow	Klingspor	Aluminium Oxide	J-Flex, Super Flexible	Finishing curved surfaces in timber and soft metals	The Aluminium oxide grit works better for softer materials,
3370EA “Gator”	Light Green	3m	Aluminium Oxide Structured Abrasive.	Flexible	Sharpening and finishing	Very consistent finish and long lasting belts in the medium grit range.

Finish Grinding Steels and Stainless Steels

For the purpose of this guide, we will define finish grinding as the point where your blade is shaped to its final shape, the bevel is ground and the plunge lines are at least ready for hand sanding. The aim here is to remove the 120 grit scratches in preparation for hand sanding or preparation for polishing. Finishing up to around 600 grit.

Most of the belts in this section will have aluminium oxide grain. Aluminium oxide is friable and breaks down quickly, exposing fresh cutting edges, allowing the belt to continue to cut through the full depth of the grain.

Some will be available in grits coarser than 180 grit and we strongly recommend not using these on steel as they degrade far too quickly. They are useful for other applications…

Manufacturers Number: Click to go to the product page and buy	Colour	Manufacturer	Grain Type	Backing	Suitable for:	Notes
3370EA “Gator”	Light Green	3m	Aluminium Oxide Structured Abrasive.	Flexible	Sharpening and finishing	Very consistent finish and long lasting belts in the medium grit range.
U264“Norax”	White	Norton	Aluminium Oxide Structured Abrasive.	Medium Flexible	Sharpening and finishing	Very consistent performance and long lasting belts for grits up to around P5000 Click Here To Buy
307EA “Trizact”	Silver	3M This belt has been superseded by Norton Norax	Aluminium Oxide Structured Abrasive.	Flexible	Sharpening and finishing	Very consistent performance and long lasting belts for grits up to around 2000 Click Here To Buy
SFS	Silver	Starcke	Aluminium Oxide Structured Abrasive.	Flexible	Sharpening and finishing	Very consistent performance and long lasting belts for grits up to around 7000 Click Here To Buy
CS310	Brown	Klingspor	Aluminium Oxide	Stiff	Fine finishing of flat surfaces	The fine aluminium oxide grit works well on all materials including hardened steel Click Here To Buy
RB346 /377	Brown	Hermes	Aluminium Oxide	Stiff	Fine finishing of flat surfaces	The fine aluminium oxide grit works well on all materials including hardened steel Click Here To Buy

Blade polishing and special finishes

Manufacturers Number: Click to go to the product page and buy	Colour	Manufacturer	Grain Type	Backing	Suitable for:	Notes
70150		Hermes	WEBRAX	Medium	Structured scratch patterns, rust removal	These belts are like a scouring pad for your grinder, they will leave reasonably consistent scratch pattern, a nice off the grinder finish on a working knife. Click Here To Buy
KORK		Hermes	Coated Cork	Medium	High level finishing of metals	Among the best belts available for finishing steel to a high level. Normally used with a lubricant like light oil, these belts rapidly blend away scratches, leaving a good finish for polishing. Click Here To Buy
PN721	Yellow	Hermes	None	Special	Finishing and Polishing	This belt has no grit. Polishing compound of the desired grade is applied, as is done with a polishing mop. A new belt should be used for each grade of compound used and belts should be kept wrapped in plastic to prevent contamination that will affect surface finish. Click Here To Buy

Handle Grinding, Shaping and Finishing

Zirconia belts lead the way in handle shaping and rough grinding. The zirconia grain is friable enough to keep cutting soft materials and yet resilient enough to cope with some grinding of metals. Once the handle has been shaped we move to aluminium oxide for the final finishes.

Be sure to try the narrow scalloped belts to get superb transitions between wood and metal guards, and well blended radiuses.

Manufacturers Number: Click to go to the product page and buy	Colour	Manufacturer	Grain Type	Backing	Suitable for:	Notes
RB4844Z	Blue	Hermes	Zirconia	Stiff	Grinding Handle materials, all kinds	These belts are sharper in nature than ceramic and work better for handle material work. They will normally last very well when used exclusively for this application Click Here To Buy
GX712	Yellow	Klingspor	Aluminium Oxide	Very Flexible	Grinding Handle materials, all kinds including tight radiuses	A sensational belt , designed to be used on a slack belt to finish all curves and transitions on handles. Rapidly becoming our most popular handle finishing belt. Click Here