Morbark 290 chipper blade question

[Jake Rosenfeld]

Friday bump back to the top.

First off, thanks for the hot tip to Alexander equipment, I ordered a new anvil and blades from them and it was a first rate, professional transaction.

Everything showed up today and I installed it all this evening. the new blades are 4" wide compared to the 3.25" that they replaced.
The new anvil looks great and it appears to be AR400 with a bead of hardfacing on the working corner that has been ground to square.
Here's my dilemma though,
At the top of the anvil at the top of the blade I can achieve a blade gap of .040 with the anvil slid almost all the way forward in the slot.
At the bottom of the anvil I can only achieve .120" blade gap with the anvil slid all the way forward in the slot.
The bottom of the top blade is .060 and the top of the bottom blade is .080 so its clear that I have a perfect taper going.

The way I see it I have two choices.
First one is to run it as is and realize that it is out of spec and will not perform perfectly but that I only have 12 acres of brush to chip so in the grand scheme of how you guys use chippers it is hardly anything.

Second choice is drill and tap a new set of holes in the anvil because I have a full 1.5-2" slot to play with and could keep the unit in correct spec as I wear it out.
I know its AR plate but theres a chance for success if I anneal the spot I intend to drill with a torch to dull red before I try. If I fail, it won't hurt the performance of the anvil in the original hole position. I've drilled it before but not tapped so I'm half in uncharted territory.....

How will the gap as I've described it affect the performance and chip size if I choose to run it as is?

I suppose I could try to hog out the slot a bit but it would only buy me a correct adjustment, not a chance of keeping it there.
How long can I expect the chipper to perform correctly on the first set up assuming it is the recommended blade gap.

thanks a ton,
jake

 

[CalTreeEquip]

Just get it as close to spec as you can and run it, see how it works for you. Something isn't adding up but it should still chip pretty good. Sounds to me like maybe you have the wrong anvil or blades. That's an old machine and it would not surprise me if someone is getting their part numbers wrong. What are the dimensions of the blades?

 

[Jake Rosenfeld]

I'll give er' a shakedown tomorrow as soon as I change the oil.
blades are 4"x 7-1/4"x3/8".
honestly, its reading more like it rolled down a mountain and got put back together crooked than anything else.
i'll run it but i'll keep looking for the problem.

 

[CalTreeEquip]

I just occurred to me that the problem might be in your disc bearings. Take a large pry bar and see if there is any movement in them.
The blades you have are the most common type for old school chippers. Those will fit old Bandits, Morbark and Woodchuck.
I think there is a 4.5" options out there but I'll have to check on that.

 

[Jake Rosenfeld]

The bearings and disc movement was one of the first things I checked when I bought the unit. After finding out here how small the blade gap is I went and took a closer more careful look. There is no play. The outer bearing is fairly new and it leads me to believe that the disc itself is in and working but not in the correct location which is keeping it too far from the anvil (and slightly tipped)
It's almost like I owned it and worked on it in a past life....

It made some chips this morning, couple more things and i'll give it a real try out at the place tomorrow.

I'll post pictures.

thanks.

 

[Jake Rosenfeld]

Well it went fine today, first thing I did is plugged er up tighter than a tick by running too much vine maple thru it at too low of rpm with the chute diverter angled too much.
Once I paid the penance of getting it unplugged and cleaned out I found the happy spot in the motor and flipped the diverter all the way up and chipped the hell out of stuff for a few hours. It did a 6" alder from bottom to top with no sweat. In fact, the only time I heard it even lean into it was when 3, 4" alders ended up in it at the same time.

I may sharpen the teeth on the feed wheels so it gets a better bite but I'm pretty happy overall.

Thanks again everyone for the help and the tips. Not having to second guess myself every step of the way has made it go much quicker.

I forgot to take pictures but as soon a I get her in a photo worthy spot i'll post some up.

later,
jake

 

[Gtatreeshrubinc]

The bearings and disc movement was one of the first things I checked when I bought the unit. After finding out here how small the blade gap is I went and took a closer more careful look. There is no play. The outer bearing is fairly new and it leads me to believe that the disc itself is in and working but not in the correct location which is keeping it too far from the anvil (and slightly tipped)
It's almost like I owned it and worked on it in a past life....

It made some chips this morning, couple more things and i'll give it a real try out at the place tomorrow.

I'll post pictures.

thanks.

I have a morbark model 290 and put new blades and anvil and there’s still a difference in gap on the upper and lower or inside and outside blades it runs smooth just big stringy chips