Bent Chipper Blades

  • Thread starter Mr. Sir
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Mr. Sir

I just replaced ANOTHER bent chipper blade in my Morbark 17. That's about the third or fourth in a year and a half. I know it's from the guys trying to chip big wood, such as live oak, but this never happened with previous chippers, including other Morbarks. Is the steel just a lower quality these days, or what? I've been buying blades from Sherrill, maybe it's time to find a new supplier. Wesspur is selling them for about 40% less than Sherrill! Does that mean they're even weaker and lower quality?

I added a couple of pics here and on Post # 21


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anvil set right? may have a sloppy bearing:what:
Never bent one either, and we've chipped miles of the biggest diameter wood I can shove into the chipper.
Not tottally sure, but I think Sherrills sells zenith knives.

I know that Zenith knives are made in Vietnam. When I bought a set of them they weared out very quickly.

I buy knives from now. They are made from North American steel and manufactured here. They last a real long time, much much longer than the zenith knives.

But they cost double.
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  • #9
I know its not the anvil or bearings. I've been on the job twice when it happened; a large diameter piece goes in and right away you can hear the blade making contact with the anvil, then a constant tic tic tic every revolution. I've been buying them from Sherrill, but I've always ordered the more expensive Simonds blades made in USA rather than the cheaper Zenith blades from Vietnam. I ordered a new set from Wesspur online yesterday and two sets from Knifesource (thanks for the link, Frans). Knifesource is priced higher than Zenith, but less than Sherrill(Simonds) and Wesspur. I'll try to get some pics for all the doubting Thomas's.
I get a lot of questions from people wondering if Zenith knives are the same quality as Knife Source knives. The answer is YES. They both get their steel from the same source (US). They both have the same A8 hardness rating, which is independantly tested by the Underwriters Laboratory. I think the price difference is explained by the higher labor costs in the US compared to Vietnam. If you do a lot of chipping, it would be a good idea to try out a set of each brand to see for yourself.

If your knives are bending, something is not right on the machine. Knives might chip from rocks etc, but they don't bend.
give enviro chipper a try, ask for levi, hes a morbark dealer and sells oem knives 800.287.2048
I have never heard of bending a knife in wood. Check your bearings and check again.

A 17 is a drum chipper right??
It can fold the tapered/sharpened side over, but if its bending at the bolts he's got big problems.
Yup, I'd be looking at the mounting hardware and confirming that the knives are installed properly. They are usually cradled in place and supported all along the body except for the 3/4" or so along the cutting edge. If somebody accidentally put some spacers or washers under the knives instead of on top of the knives then they could be subjected to additional stress.
We need to see a pic. I think he may meen the edge is rolled over?
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  • #18
Nope, it is bent, like this (

Not quite THAT much but you get the idea. I install them myself, so I know its done properly. There's the drum, a knife, the knife clamp, and four bolts; not a lot you can mess up there. The bearings are fine, absolutely no play. The anvil is original and hasn't moved; I can tell by the paint. And every time this has happened its been while chipping large diameter live oak.

The knives are manufactured to be slightly softer around the bolts holes to prevent cracking. The sharp edges are harder according to several dealers I've spoken to. Apparently Sherrill purchased a batch that is a bit TOO soft in the center.
I had some that were tempered too much is the only thing I can think of. They would chip good on warm days. But when it was real cold they would just shatter, First small limb of the morning would explode them. 2 sets from the same company, produced the exact results. I thought something was out of line I spent and entire day inspecting and checking tolerances. Overnighted new blades from different company, magic fix.

No more order from first company.
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  • #21
Pics of Bent Chipper Knife

Here it is:


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  • #24
I have four of them, that's the worst one. Sherrill told me to send them back for "inspection."