The ABCs of Selecting a Valve Seat Grinding Stone

By Dave Monyhan,

Valve Seat Grinding Stones have been around for a very long time. Back in the day there were roughing and finishing stones. This was because way back when seats were generally made from common cast iron or hardened steel. Two abrasive specs for the stone was all that was needed to properly grind the valve seat.

Today it is another story altogether as the seat material has become very specific to the applications found on today’s engines – alloys of multiple metals, powdered metals, super hard materials all designed to prolong the ability of the seat to seal against the valve head.
To meet these various needs, Goodson Tools & Supplies offers six different abrasive formals for grinding valve seats.

  • General Purpose
  • Stellite
  • Nickel Chrome
  • Cool Blue
  • Finishing
  • Ruby

With so many to choose from, the big question is what do I use for what seats? I won’t get into General Purpose or Finishing as most of you already know about those abrasive specs.

Stellite is used in many various components and is composed of 75 to 90% Cobalt and 10 to 25% Chromium with or without small amounts of other metals added. It is used especially for cutting tools, hard wear-resistant surfaces, surgical instruments, and cutlery. In our industry, we see it primarily in valves and valve seats. Stellite is a hard material that is very durabel, and provides extended life to both the valve seat and engine valve. As you know, to grind a hard material you need a softer abrasive that will continually break down and deliver the ability to remove material without immediate load up. The Goodson Stellite abrasive was designed specifically for this material.

Nickel Chrome is defined as a stainless steel containing 8% Nickel and 18% Nickel Chrome is very resistant to wear and chemical reaction. Wow that a big definition, huh?

So where is Nickel Chrome used? It’s used in valve seats where we have a severe duty application such as air compressors, diesel earth movers and even some over the road trucks. Nickel Chrome has a hardness range of 42 to as much as 50 Rockwell so it requires a softer abrasive combined with a bond to keep the abrasive particles sharp and able to breakdown to grind through this hard material. The Goodson Nickel Chrome seat grinding stone is designed specifically for use on these hard materials.

Cool Blue is an abrasive spec created by Goodson specifically for grinding the Copper Beryllium valve seats found in high-performance applications.

Time for some technical definitions …

“Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze and spring copper, is a copper alloy with 0.5—3% beryllium and sometimes with other alloying elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has excellent metalworking, forming and machining qualities. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and aerospace.”
Wikipedia

In solid form and as finished parts, beryllium copper presents no known health hazard. However, breathing its dust or vapors, as formed when machining or welding, will eventually cause serious lung damage. Beryllium compounds are known human carcinogens when inhaled. As a result, beryllium copper is sometimes replaced by safer copper alloys such as Cu-Ni-Sn bronze.

I will admit we were surprised not only by how well Cool Blue abrasive worked for the Beryllium seats but also for other types of seat materials such as diesel and other extreme duty applications.

Ruby The final abrasive formula we’re going to talk about is the ruby or red seat wheel abrasive. The Goodson Ruby Stone is our best aftermarket replacement for the original Black and Decker spec. This spec was designed for use as a general purpose wheel to grind most seat alloys from the late 60s to the early 80s.

So, in this article, we’ve given you a brief overview of the various abrasive formulas Goodson offers in Valve Seat Grinding Stones. Watch for the rest of the story when we talk about seat stone dressing, stone holders and more.

One last thing, and we can’t say this enough, ALWAYS USE RESPIRATORY PROTECTION WHEN GRINDING VALVE SEATS! 

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