I had a discussion with this customer, not about how things like Carbide Weld and how much weld, but more on the style of tips.
Whether you call them Chipper style, Bear Claw or bullet tips, the actual effectiveness of the tips comes down to how much surface area of the tip is contacting the wood. The wider and flatter the tip, the more horsepower you will need to power through logs and trees. The less surface area contacting the wood, the more efficient the cutting action is on logs and whole wood.
So which style works best for you? Here are a few general descriptions and the consequences of using these styles:
- Standard 2 sided, flat tips — Generally the least expensive. Can be flipped and used on the opposite side too. Can have many lines of carbide impregnated weld or only a few. These are a general purpose tip. Using on a regrind application gives you the best looking mulch product because it is wider than others contacting more wood at a time and because of the width, it sweeps the screen clean and pushes the material through the screen holes. When grinding whole trees or logs, because of the width, it is like hitting a log with a sledgehammer. You will need more horsepower. One major factor when choosing these tips is the amount of carbide surfaces. So how do you select the right amount? When the tip is worn enough for changing, take a good look at how much carbide is left on the tip and where it is located. There is no reason to pay for carbide surface on the side of the tip if there is 90% of it left when the top of the tip is worn too much and it needs to be changed. Find a less expensive tip without that surface carbided and save yourself the money.
- Bear Claw — These tips look like a standard flat tip but with claws coming out the top. In general, these “Claw Like” protrusions are made of solid carbide. Carbide is very hard and wears very well, but it is so hard it is brittle. One rock or one piece of steel and the carbide explodes and disintegrates off the tip turning it into a flat tip again! Because of the protrusions out the top, downsizing stumps and logs can be done efficiently. And the carbide wears very well provided you do not hit anything hard in the material you are grinding. But the draw back to these tips is the cost. Because carbide is so expensive and these tips use solid carbide, expect to pay 3-4 times the cost of a standard tip.
- Chipper style — These tips are very aggressive on whole trees and big wood. Because they come to a sharp flat edge with minimal surface area, powering through big wood makes a 500 horsepower grinder grind like a 750 or 1000 horsepower grinder. The downside is that they wear very quickly. But even when they wear the sharp edge away, they still have less surface area than a flat tip. These can also be sharpened, just like a chipper knife. A few minutes with an angle grinder and you have your sharp edge back. There are no carbide welds on these tips, so they will wear quickly compared to a carbide surfaced tip, but production wise there is no comparison.
- Bullet style — These tips are the same as an Asphalt grinding machine or trencher. Splintering wood is very effective but the material produced looks like a lot of 2-3” wide, 12- 18” long pieces. If you install small screens to downsize the material, these tips wear out quickly. For shear reduction, they work well, but the longevity is not very good at all. While cost is generally cheaper than the flat tips, if you use 60 of them or so, it’s a lot of money for the wear life.
So what do you do? Try them!
- Install a ½ set of flat with a half set of chipper or bear claw. Then try another ½ set style.
- For maximum reduction, try a whole set
- Figure Cost- usage life vs production and compare
- While you may be able to reduce quickly, not having a flat larger surface area tip at all, may not move material through the screen and out of the grinding chamber fast enough.
- While parts cost may be double, being able to finish a job in 1 week rather than 2 weeks saves a whole lot of other costs. So the parts cost may be insignificant in the overall scheme of things.
Not trying something new, never gives you the opportunity to improve. Keep trying different styles until you find a cost and production rate that can increase your performance and generate a greater profit.
Questions? Dave Whitelaw, The GrinderGuy firstname.lastname@example.org