Home |
Search |
Today's Posts |
|
Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
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. For the time being I used a old but unused heavy duty mower blade which was as hard as a leaf spring is, and cut it to size and have been using it, but it does not quite hold up as good as the original blades did, but its still useable. The original is supposedly hardened to 58 rc. So what materials would you recomend making this blade out of.? I don't really have a temp controlled furnace, but I maya be able to acccess one, unless I can get by on heating with a torch or in my crucible furnace. Any info appreciated. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy. |
#2
|
|||
|
|||
Info on how to make a chipper knife
Why not mill a step into a properly sized blank and braze in some carbide?
You ain't making veneer so it could be a few smaller pieces brazed in. Only the edge needs to be hard. |
#3
|
|||
|
|||
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. Roy, 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. Pat |
#5
|
|||
|
|||
Info on how to make a chipper knife
Roy wrote:
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 like the idea of milling a step and brazing in some carbide........ I don't like the carbide idea as carbides are brittle and chip easily. I too am a cheap SOB Not as cheap as me! ;-) I would try the following: Cut the blade out of a piece of old (free) leaf spring (plasma or O/A). Anneal, flatten, drill the holes and roughly shape the edge. Build up the edge with Stellite #6 (TIG or O/A). Grind the edge to finished shape and sharpen. You can then harden and temper to purple for additional strength if you wish. The heat won't affect the Stellite. You may have to sharpen it once after some use as the Stellite work hardens. BTW, I picked up a box of Stellite #6 TIG rods at a blow out sale at the local welding shop. Stuff is expensive but that knife wouldn't take even half a rod. I've made center punches for hot work out of tipped re-bar scrap and even used it for some heat resistant electrical contacts. Well worth having a few rods around. I loaned a friend a cold chisel I made from a piece of 1" re-bar. I forged it to shape with a very blunt square edge. I built up a bead of #6 Stellite on the edge and ground to shape and sharpness. He wanted it to clean off lumps of concrete left from knot holes in the forms. I fully expected it to come back in pretty bad shape but I was curious to see what would happen. Well, I found out! The edge was a little dulled - not worth bothering to sharpen yet. No chips. Ted |
#6
|
|||
|
|||
Info on how to make a chipper knife
On Fri, 31 Oct 2003 23:37:36 GMT, (Roy) wrote:
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. For the time being I used a old but unused heavy duty mower blade which was as hard as a leaf spring is, and cut it to size and have been using it, but it does not quite hold up as good as the original blades did, but its still useable. The original is supposedly hardened to 58 rc. So what materials would you recomend making this blade out of.? I don't really have a temp controlled furnace, but I maya be able to acccess one, unless I can get by on heating with a torch or in my crucible furnace. Any info appreciated. I'd try some 1/4 x 1-1/4" W-1 or O-1 flat bar (from MSC or Enco?). Cut it to length, mill the bevel, drill and countersink the holes. You should be able to harden those with an O/A torch. That should get you a blade that is RC 63 (O-1) to 66 (W-1) or so, a one, hour 500 degree temper should drop that to RC 58 or so. If you only have a home oven, an hour at 400 will get it down to RC 61-62 or so and that may work okay for a wood chipper. You can get 9 blades our of a 36" piece of O-1 or W-1 which I would guess at around $60 or so. Your time does not count when you're working for yourself right? :) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Drilling a rock to make a water feature? | UK diy | |||
Knife Steel FAQ updated | Metalworking |