chipper knife gap setting

[Davidsinatree]

I have a Pro Mark 210 chipper that has two cutting edge blades. One side was dull so I wanted to flip them over to the sharp side. I pulled the side covers and chute off to see the bed knife and was a little shocked at what I saw, there was almost 1/2'' clearance between knife and bed. The service book says to set clearance at .020 to .030. No damage apears to have been done. I'm thinking when I get it back together at the right gap setting perfrmance should be much better. I thought it chipped pretty good before.
What are some of the clearances on other chippers. What are some tricks you use to set gaps. I also have tree bolts that will not break loose, so i'm in the process of drilling them out. Any tips on removing knife bolts also. They are 7/16 level head screws with jam nuts that back them up.

 

[Stumper]

Good advice from Brian. I had to drill out some stripped and seized knife bolts on mine also. I use anti-sieze and torque to specs and have had no problems since. If you have a calibrated eyeball you can set your knives visually. On mine 70thousandts will cause noticably rougher cutting than .035. One tip for improved feed on these little guys-sharpen the bed knife! having a good square corner on the bed/anvil will really help self-feeding.

 

[okietreedude1]

Although I dont know just how thick it is, we use a blade from a hacksaw and leave 'breathing room' around it.

We too use anti-seize compound on all knife bolts when reassembling them. It may not help now, but it will in the future. As for now, you might have to go to a mechanic w/ impact tools. Put your impact on the nut side.

Best of luck!

 

[rbtree]

A sharp cutter bar/anvil/bed knife is important on all chippers for chip quality.

I set the knife gap as small as possible, always less than factory specs. This too makes for a better chip.

 

[Menchhofer]

I also agree your anvil needs to have a square edge to it.

With regards to the knives, on a small machine such as yours, they need to be very sharp at all times for best performance.

You should also replace the bolts and nuts w/probably grade 8 bolts and locking nuts. No lock washers.

Although this does not relate to the post, I thought I would add when I had a small machine I did not care for the noise from the stock, smaller mufflers. I installed larger car-like mufflers on the engine and this cut down on over 1/2 the noise. Only cost about 85.00 too.

Clearance from knife edge to anvil? For years I measured about .30 gap until mechanic told me the best way is to sight the gap until the knife is just barely enough away from the anvil for clearance, or just enough to be able to see light between the two edges (depends on how in balance your disc is). This has worked fine for me and makes good quality chips.

I do not think I would put grease or oil (sorry Rocky) on the threads..instead anti seize compound would be better.

 

[Lumberjack]

Originally posted by Menchhofer
I do not think I would put grease or oil (sorry Rocky) on the threads..instead anti seize compound would be better.

He was reffering to breaking the bolts loose, to use a penitrating oil. Then either Rocky or someone else said to use antiseeze to prevent this from reaccuring.

 

[Menchhofer]

Grease the bolt threads before re-installing to make it easier next time. [/B]

I only mentioned this due to the fact I just read that putting grease or oil on lug nuts/bolts on your car was not recommended as this can cause the nuts to loosen up.

 

[Lumberjack]

Originally posted by Menchhofer
I only mentioned this due to the fact I just read that putting grease or oil on lug nuts/bolts on your car was not recommended as this can cause the nuts to loosen up.

That is the point. They are trying to remove the bolts to flip the blades over to the sharp side.

 

[NeTree]

The knife/anvil clearance only gets really critical on drum self-feeders. They're typically set at .010", and the chip quality goes downhill FAST the larger the gap gets.

I use either "Loosey-Goosey" (tough to obtain), or Cyclo "Break-Away" as my preferred nut-breakers. (smirk). They work better than WD or PB.

 

[Xtra]

I was told by the factory service mechanic that (for a disc 250 Brush Bandit) to allow just enough room to slide a plastic packing strap between the blade and anvil.

Here a site with some extra info on chipper blades -- http://www.envirochipper.com/service_bulletin.htm


- Bob