View Single Post
  #3   Report Post  
Old November 1st 03, 06:36 AM
Posts: n/a
Default Info on how to make a chipper knife

Being that one of my knives on my chipper broke and I am a cheap son
of a bi%#@ i need to make one. Its approximately 1.25" x 3.75" x .250"
thick, with two 5/16" countersunk holes in it and a bevel of 37 deg
ground on one long edge.

I had a similar problem with a 10 HP Murray chipper-shredder. It had one
blade, 1.375 X 3.125 X 1/4 with two 5/16 countersink holes and a similar bevel.
This was a shi**y design. The blade was too short to begin with, allowing a
sliver of a green branch to slip by the inside end and wrap around the axle.
It was also of the wrong material. The original blade fractured through a bolt
hole, and a replacement was priced at about $24 + shipping cost.

I went to the farm store and bought the cheapest plowshare in stock for about
$7, and hacksawed out a blank and worked it from there -- mill, drill,
countersink, grind. I made my blade 3.625 long, and it works like a charm. No
fractures. No wraparound. And priced to please the cheapest son of a bi%#@
on earth. After some experience, I tried grinding more "clearance" in my
blade, and it literally sucks the branches in. (The original had to be force
fed.) And I have a lifetime supply of material for more blades.

Overall comment on this chipper: The chipper body and rotor do not have the
strength to take 10 HP. I have about a pound of weld on mine, repairing over a
foot of fatigue cracks and reattatching parts that were blown away. The
rotating flails were mounted on weakened pins which failed, with results
approximating an explosion.

Try the plowshares for a source of cheap, tough steel. They're designed for
fatigue strength and wear resistance. Milling it will test your skill and
vocabulary. Say carbide, and then have fun.