Stump Grinder Built For $250

2016 - Volume #40, Issue #3, Page #24

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Mark Yax used mostly off-the-shelf automotive parts to build his own stump grinder for only about $250.
    The stump grinder rides on 10-in. pneumatic tires and has handles made from 7/8-in. cold-rolled steel. It’s powered by a Tecumseh HM80 engine that Yax already had. The engine mounts on a welded 2-piece square tubing frame and is used to double belt-drive the centrifugal clutch to the grinder’s teeth.
    The operator grabs a T-bar handle to guide the unit. Yax mounted hand brakes on the handles so he can lock one of the wheels in place, allowing him to pivot the machine back and forth as he grinds the stump.
    “I designed it as simple as possible and used mostly parts I already had,” he says.
    He bought the brake rotor and rear axle bearing from a front wheel drive car, and a dual belt crankshaft pulley from an auto parts supplier on eBay. He also bought two #40 chain sprockets from a tractor supply company and welded them to the wheel rims. Pins that retract with the hand levers engage in the sprocket teeth and lock the wheels independently.
    He used 1/8-in. plate to form a guard for the grinding wheel to keep wood chips from flying back at him.
    “I’m pleased with how it turned out,” says Yax. “The stump shown in the photo was about 18 in. dia. and 6 in. above ground when I started on it, but I had the stump and roots ground out to about 4 in. below ground level in only about 20 min.
    “I wanted to keep the design as simple as possible, so that very little machining was required. Most of the parts I used were fabricated with a drill press, 4-in. angle grinder with cut-off saw, and welder. Some machining was required for the cutting tool holders and the bearing mount. I bought the belt pulley, brake rotor, bearing and cutter teeth and tools for about $250. Everything else that I used, I already had.”
    To build the cutter assembly, Yax used cheap carbide lathe tools that he bought on eBay for only about $3 apiece. He used 20 carbide-tipped teeth on the cutterhead. “I bought 10 left hand teeth and 10 right hand teeth and bolted them to some 1 1/2-in. dia. steel round stock with slots milled in that bolt onto the cutter wheel,” says Yax. “I also pinned the cutters through the brake rotor to make sure the cutters won’t fly out.”
    Since he only uses the stump grinder occasionally he made a belt-adjusting system that works off one bolt. “By removing the bolt I can quickly remove the engine and use it on other equipment that I intend to build,” says Yax.
    Yax documented the complete building process. “If there’s enough interest I’ll offer CAD drawings for sale with a complete list of components and part numbers that I used to build it,” he says.
    Contact: FARM SHOW Followup, Mark Yax, Valmark Tool, 36755 Pettibone Road, Solon, Ohio 44139 (ph 440 248-1894; valmarktool@aol.com).

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Stump Grinder Built For $250 WOODLOT EQUIPMENT Miscellaneous Mark Yax used mostly off-the-shelf automotive parts to build his own stump grinder for only about $250 The stump grinder rides on 10-in pneumatic tires and has handles made from 7/8-in cold-rolled steel It’s powered by a Tecumseh HM80 engine that Yax already had The engine mounts on a welded 2-piece square tubing frame and is used to double belt-drive the centrifugal clutch to the grinder’s teeth The operator grabs a T-bar handle to guide the unit Yax mounted hand brakes on the handles so he can lock one of the wheels in place allowing him to pivot the machine back and forth as he grinds the stump “I designed it as simple as possible and used mostly parts I already had ” he says He bought the brake rotor and rear axle bearing from a front wheel drive car and a dual belt crankshaft pulley from an auto parts supplier on eBay He also bought two #40 chain sprockets from a tractor supply company and welded them to the wheel rims Pins that retract with the hand levers engage in the sprocket teeth and lock the wheels independently He used 1/8-in plate to form a guard for the grinding wheel to keep wood chips from flying back at him “I’m pleased with how it turned out ” says Yax “The stump shown in the photo was about 18 in dia and 6 in above ground when I started on it but I had the stump and roots ground out to about 4 in below ground level in only about 20 min “I wanted to keep the design as simple as possible so that very little machining was required Most of the parts I used were fabricated with a drill press 4-in angle grinder with cut-off saw and welder Some machining was required for the cutting tool holders and the bearing mount I bought the belt pulley brake rotor bearing and cutter teeth and tools for about $250 Everything else that I used I already had ” To build the cutter assembly Yax used cheap carbide lathe tools that he bought on eBay for only about $3 apiece He used 20 carbide-tipped teeth on the cutterhead “I bought 10 left hand teeth and 10 right hand teeth and bolted them to some 1 1/2-in dia steel round stock with slots milled in that bolt onto the cutter wheel ” says Yax “I also pinned the cutters through the brake rotor to make sure the cutters won’t fly out ” Since he only uses the stump grinder occasionally he made a belt-adjusting system that works off one bolt “By removing the bolt I can quickly remove the engine and use it on other equipment that I intend to build ” says Yax Yax documented the complete building process “If there’s enough interest I’ll offer CAD drawings for sale with a complete list of components and part numbers that I used to build it ” he says Contact: FARM SHOW Followup Mark Yax Valmark Tool 36755 Pettibone Road Solon Ohio 44139 ph 440 248-1894; valmarktool@aol com

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