Chipper blades, restoring w welding, advisable or not ?

[pondnstream]

We need to sharpen our chipper blades more often and repair the edges when they get gouged. Sharp blades make a huge difference.

Has anyone had any success restoring deeply gouged chipper blades by filling in the low area with weld metal and re-grinding ?

I imagine that these chipper blades are hardened steel and the intense heat from welding would cause the steel to lose its properties around the joint.
Perhaps preheating and slow cooling would help but I thought I'd ask.

 

[capetrees]

We need to sharpen our chipper blades more often and repair the edges when they get gouged. Sharp blades make a huge difference.

Has anyone had any success restoring deeply gouged chipper blades by filling in the low area with weld metal and re-grinding ?

I imagine that these chipper blades are hardened steel and the intense heat from welding would cause the steel to lose its properties around the joint.
Perhaps preheating and slow cooling would help but I thought I'd ask.

No way I'd try that. I don't know what you chip or why they get so badly beat up but I've had blades let loose off the drum and it ain't pretty. Broken blades could destroy the drum and bearings and who knows what else. If they get chipped and chunked that bad, watch whats going into the feed but I wouldn't weld anything to the blades.

 

[ClimberBusinessman]

My understanding is that you don't mix and match new and old blades at the same time on the same chipper, because it throws the weight balance off and makes it vibrate badly, which is bad for the machine. I'd expect welded blades to vary at least a little bit from normal blades in weight, so you'd end up with the same or worse issue that mixing and matching would do. Also, your welding better be 100% perfect, or as capetrees said, they'll fall apart and destroy the drum. Welded blades are not a good idea. Normally you should replace them ahead of that time that they fall apart to the point you have to weld them.
Just charge customers enough to properly maintain your equipment (including new chipper blades from time to time), have worker's comp and general liability insurance, and run as safe and legit an operation as possible.

 

[TheJollyLogger]

Yeah, not a good idea at all. I'm also curious what you are chipping that is beating them up so badly? I know I went to work for a company that threw everything through the chipper, including the rakings. As soon as the rakings started going straight to the back of the truck knife wear improved dramatically.

 

[northmanlogging]

chipper/planer blades are very high carbon steel, hardened too
Welding them would be a very bad idea, in the bang, whistling death kind of way.
Besides last I checked they weren't exactly expensive to replace, and if you treat them well they should last awhile.

 

[TheJollyLogger]

When we would send them to be sharpened, they would always come back in matched sets so the weight was that equal.

 

[Sidecarflip]

When we would send them to be sharpened, they would always come back in matched sets so the weight was that equal.

Exactly what I do when I grind them, they all get matched by weight. Chipper blades are all through hardened high carbon tool steel and welding on any of them is inviting disaster.

Don't ever do that. Buy new ones and evaluate your procedures and determine what is eating them up and refrain from doing it. They all get buggered after a time, if not I would not be grinding them in the first place.

When I get knives in to be ground and they have a huge divot in the chipping edge, I don't even bother grinding them. They go in the scrap can.

If you are eating up knives you are also eating up the anvils as well. Sharp knives with a buggered anvil is worthless.

 

[blades]

The number one reason chipper knives get gouged up is shoveling everything into chipper. These are not rock crusher units ( although some seem to treat them that way). It is part of the work for the blades to find that rogue rock or steel that has been swallowed by the tree. Blades go though a double type of hardening much like a cold chisel. Welding causes stress points that can cause the blade to fracture and dis-intergrate. Been grinding sharpening chipper blades for 30+ years heard just about every story/ excuse there is. You should never run worn or extremely dull blades- all that is doing is destroying the machine. which will ultimately cost you time and money down the road. With the cost of steel rising some 75% over the past five years - blades , like everything else, have gotten a bit dear to purchase. When replacing or reinstalling sharpend blades always use a new set of bolts and nuts, torqued to spec- cheap insurance.

 

[Sidecarflip]

Myself, I never question what my customers do with their chippers or what they run through them. I just get the aftermath of their actions and I'm good with that actually.

Far as quality chipper knives are concerned, they are through hardened and stress relieved.

 

[blades]

As it was told to me by a mfg, it is a bit more than that as the second step hardens the edge area but leaves the central area bit more mallable - prevents cracking around the mounting bolts. I have had blades come in that were wallerd out in the mounting holes due to improper tightening. found some over the years with hair line cracks. one set was so dull that the blades were burned with pretty blue and golden overtones.

 

[TheJollyLogger]

The number one reason chipper knives get gouged up is shoveling everything into chipper. These are not rock crusher units ( although some seem to treat them that way). It is part of the work for the blades to find that rogue rock or steel that has been swallowed by the tree. Blades go though a double type of hardening much like a cold chisel. Welding causes stress points that can cause the blade to fracture and dis-intergrate. Been grinding sharpening chipper blades for 30+ years heard just about every story/ excuse there is. You should never run worn or extremely dull blades- all that is doing is destroying the machine. which will ultimately cost you time and money down the road. With the cost of steel rising some 75% over the past five years - blades , like everything else, have gotten a bit dear to purchase. When replacing or reinstalling sharpend blades always use a new set of bolts and nuts, torqued to spec- cheap insurance.

+1 on new bolts, and follow torque specs... or just keep a spare set of skivvies for the whole crew in the truck for when a blade let's go...

 

[sonny580]

NEVER weld on any blade like that!!! good way to get somebody killed! Chippers aint toys so stop using it as one and get serious about what you put thru it!

 

[Sidecarflip]

I keep an assortment of blade bolts on hand so if my customers want the, I have them (for a price of course) Fastenal has all of them in stock.

 

[ZinTrees]

just buy new knives, they are $40-50 each, bolts too while you are at it, quit shoveling stuff into the chipper, what gets left behind the feed tray NEVER gets put in the chipper, EVER
if they are dinged up so bad you need to weld them up to fill in, then you need a new chipper operator and take maintenance more seriously
welding the knives will create heat affected zone, mess up the carbon content, and most certainly result in thousands in repairs and maybe someone being hurt or killed, which also equals a phone call to OSHA and a massive headache

spend $250 on knives and bolts, or $250K in medical expenses

 

[lone wolf]

When we would send them to be sharpened, they would always come back in matched sets so the weight was that equal.

Well, if they aren't even in measurement, not only will the machine vibrate, but you won't get a nice tight clearance at the cutting bar! It seems all the people I talk to don't even know about the cutting bar or how to adjust it, they just keep throwing resharpened knives in there which make the gap bigger and makes larger chips.

 

[ZinTrees]

Well, if they aren't even in measurement, not only will the machine vibrate, but you won't get a nice tight clearance at the cutting bar! It seems all the people I talk to don't even know about the cutting bar or how to adjust it, they just keep throwing resharpened knives in there which make the gap bigger and makes larger chips.

my anvil backed off, bolts were super tight too, maybe something (rebar maybe) got mixed in and shoved the anvil back about 1/4" and rounded the corner, flipped the anvil and set the gap till it will almost pull a business card from between my fingers, maybe 10 thou gap? chips real nice and I haven't had an issue hitting the anvil in 2 years

 

[Sidecarflip]

Cutting bar??? You mean the anvil and the anvil will have 4 working edges. The knives don't set the gap, the anvil dies. Knives are all stationary.

 

[Sidecarflip]

When I set them up, I use an old credit card to gage the gap.

 

[ZinTrees]

Cutting bar??? You mean the anvil and the anvil will have 4 working edges. The knives don't set the gap, the anvil dies. Knives are all stationary.

cutter bar, anvil, theres probably 5 or 10 names for it, as lone wolf said, most people dont know the anvil has to be adjusted

 

[lone wolf]

Cutting bar??? You mean the anvil and the anvil will have 4 working edges. The knives don't set the gap, the anvil dies. Knives are all stationary.

Well, yeah, the cutting bar. I mean improperly cut knives can be different measurements when sharpened if they don't know what they are doing and can cause a problem gapping the knife to cutting bar Clearance, see what I mean? I had it happen once and had to have the whole set done over at another shop.