Martin® vs. BlackStar® Sprockets
Why choose martin sprockets?
Martin® is the most well-known name in roller chain sprockets in the US. That leadership position caused us to select Martin for this product comparison. There are several differences between Martin and BlackStar® sprockets. The video below will examine those differences to reach a verdict about the quality of each brand.
Let’s begin by examining the characteristics of roller chain drives.
With roller chain drives, the small sprocket always rotates at a higher speed. Each tooth engages the chain more frequently, subjecting it to a greater load. This makes the smaller sprocket more susceptible to damage and wear.
Sintered or solid steel sprockets?
Martin sells both sintered and solid steel sprockets. However, when examining their catalog, you may notice the omission of certain important specifications. Martin simply refers to theirs as “All Steel” and they do not differentiate between sintered or solid steel. When you order a sprocket from Martin, you don’t know what you’ll receive.
All BlackStar sprockets are made from solid steel. There is no mystery.
Why make a sprocket from sintered steel?
Sintered components are formed from powdered metal. These are cheaper to produce but are prone to cracking, fracturing, and are difficult to machine. Because the sintering process makes it difficult to produce large items, only smaller sprockets are made of sintered steel.
Independent sprocket testing.
BlackStar submitted both a Martin sintered steel and BlackStar solid steel sprocket to an independent test lab. We were astonished at the results.
Increasing force was applied to individual sprocket teeth until they reached their breaking point. The force required to break a sintered tooth was not even close to that required to break a solid-steel one. Sadly, these sintered sprockets see use in the most vulnerable part of a chain drive!
On average, a sintered tooth broke at 1606 lbs of force. In contrast, it took 7280 lbs of force to break a BlackStar solid-steel tooth. That’s an incredible 353% difference.
Sprocket density plays a role in wear resistance.
Compare these unretouched photos; On the left is a Martin 60BS19HT straight out of the box. Notice the porosity in the gullets where the chain rollers ride? On the right is a BlackStar H60BS19. Which sprocket would you want your chain riding on? Which would you be willing to pay more for?
Density plays a major role in wear resistance. Because the sintering process makes a more porous product, Martin’s sintered-steel sprockets are more susceptible to wear. BlackStar solid-steel sprockets are 12% denser! They are more wear-resistant. BlackStar sprockets are not prone to this sort of breakage.
Solid-steel sprocket testing.
Because Martin does not specify a material for their solid-steel sprockets, BlackStar conducted further testing by sending a Martin sprocket for metallurgical analysis. The lab found that the sprocket was made of AISI 1025 steel. All BlackStar sprockets are made of 1045 steel. 1045 is harder and stronger than 1025.
The Brinell hardness of 1045 is 163. The Brinell hardness of 1025 is 111. This increased hardness is particularly important in larger sprockets that rarely come with hardened teeth except by special order.
The ultimate tensile strength of 1045 steel at 84,800 psi far exceeds that of 1025 at 55,100 psi.
The verdict is in.
To sum it up, small sprockets have a big job, and they need the strength to do it. Martin sells sintered steel sprockets on sizes up to about 5 inches in diameter. However, EVERY BlackStar sprocket is made of solid 1045 steel. There is simply no question about which is tougher. When comparing sintered steel to solid steel, BlackStar definitely wins.
Because Martin’s larger sprockets are made of 1025 steel, they are not as strong or wear-resistant as the 1045 steel used in all BlackStar sprockets. Even when comparing solid steel to solid steel, BlackStar wins again!
Quality sprockets without added premiums.
Unless you pay a premium, Martin sells sprockets without hardened teeth. Depending on the size, this premium can be somewhere around 50%. On the other hand, BlackStar solid-steel sprockets come standard with induction hardened teeth on the sizes that need them most.
BlackStar does not take a back seat to Martin on any aspect of quality. It is quite the opposite. For the well-informed buyer more concerned with the quality of the product than the brand name stamped on it, BlackStar is the obvious choice.