# Does anyone know how far out from the drum to adjust the knifes ?



## Buzzsaw22 (Mar 31, 2013)

Im restoring a 1960 D model Aspunldh drum chipper an need to know how far out the knifes should be adjusted from the drum before adjusting the chop block up


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## pdqdl (Apr 1, 2013)

Not really.

That being said, I have some advice in general, based on my experiences with my ancient Olathe 12" chipper, a basic chuck-n-duck drum chipper. No specs were available on it, either, and I eventually figured out what worked well.

The amount of knife extending from the drum determines your feed rate and the size of chips you are going to make. If it sticks out too far, it will hammer hard into the wood and suck all the momentum out of your flywheel. You need a big engine to have your knives constantly taking big bites with every rotation.

If your knives are not out far enough, your chipper will have a tendency to not pull the wood in, and then you are losing a lot of time stuffing the branches into the chipper.

A good place to start the diagnosis is by checking the clearance between the bed knife or "anvil" and your blades. Chances are good that the bed knife is set about right, so adjust your drum knives out until you have about 1/10th of an inch clearance. Then adjust your bed knife up until you have around 50/thousandths clearance. .050 clearance is probably quite a bit, but you want to make sure that your drum bearings don't allow the knives to contact each other. It is better to have too big a gap than allow it to close with destructive consequences.

When your bed knife gap is too wide, you will be throwing long stringers into the truck, rather than chips.

Does this machine have a drop-table mechanism to stop the wood from feeding? Make sure that it is adjusted so that it CANNOT bounce up and hit the rotating knives. Bad things happen when you don't know to check for this! Also, the raised height of this mechanism will seriously affect how well the chipper feeds.


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## Buzzsaw22 (Apr 1, 2013)

Heres a couple pictures of it , Anvil has two bolts on bottom to raise an lower it an two on side to hold it in place The anvil has a hole cut for it were it jus drops out off the bottom of the floor seems pretty basic not much the can be adjusted . There are two bolts that push the blade out from the drum an wasnt sure how far to adjust them out . People that i got the chipper from hade the knifes sharpend but didnt adjust the knifes out an it woulndt chip anything jus kick it back so they was think there was something broke an sold it to me but seems to be a simple fix i think . Thank You very much for the info on it . .


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## pdqdl (Apr 1, 2013)

My Olathe chipper had a drop-table that was controlled by a lever. Dropping it caused all wood to be chipped incorrectly and the feed would be instantly stopped...mostly. *Your machine does not seem to have that feature.*

I cannot imagine that the bed knife has no adjustment. This is a part that wears and needs to be machined regularly to keep the chipper sharp. They typically bolt down against a steel frame held close to perpendicular away from the drum, with adjustment bolts beneath the bed knife to give the installer some up/down control prior to tightening the hold-down bolts. Look closer; I am sure they were there once upon a time. 50 years later, someone probably broke the rusted up bolts out or stripped the holes, leaving you a dysfunctional machine. I had similar issues with my machine.

If the bed knife and chipper knives are set too high, then any branch going through the chipper will have an uncut ledge of wood that stops the feed. Here is a poor sketch that leaves out a bunch of details:







If the bed knife is too high, it leaves a ledge of wood that remains uncut and the wood immediately stalls in the chipper when it stops against the bed knife. _I suspect that this is your problem_. Once the bed knife is at the correct height, then the chipper knives need to be individually set to the proper clearance from the bed knife so that the chipper does not throw "stringers" of wood out the chute (thereby increasing the probability of plugging up the discharge). 

At the same time everything is being adjusted, you *MUST* make sure that none of the chipper knives can contact any steel elements during the chipping process. This would include the feed table, the bed knive, or any of the enclosure. Any movement of the drum itself on it's bearings or any of the movable parts can cause this problem, in addition to incorrect adjustments. Failure to do this will cause an explosion of rapidly destructive flying metal parts.


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## pdqdl (Apr 1, 2013)

It would probably be a good idea to make sure that your bed knife has been machined absolutely straight. This is commonly done by the same folks that sharpen your chipper knives.

I do my own on my RBG grinder. I just clamp a stop onto the grinder table and feed the knife through in many passes taking small grinds off with each pass. Most grinders are poorly suited to this; don't even think you can save money or time by hand grinding it straight enough. You need absolutely straight, not just "kinda straight".


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## pdqdl (Apr 1, 2013)

Diagnostic afterthought:

Stick a 6" branch in your chipper, then do some analysis on the rejected end. Look carefully at the thickness of the ledge that is not chipped and the shape of the partially chipped end.

The answer to your problems can be found by starting to look there.


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## Steve-Maine (Apr 1, 2013)

I can send you a copy of an an Asplundh Model JEY manual. should be same adjustments as yours. It id very important that bed knive is perfectly square or your wasting your time. Anybody that grinds chipper knives can grind the bed plate.
[email protected] Falmouth, me





pdqdl said:


> Diagnostic afterthought:
> 
> Stick a 6" branch in your chipper, then do some analysis on the rejected end. Look carefully at the thickness of the ledge that is not chipped and the shape of the partially chipped end.
> 
> The answer to your problems can be found by starting to look there.


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## Buzzsaw22 (Apr 1, 2013)

Yes you are rite there is adjuster screws behind the knifes an when i bought this chipper the own said that they had the knifes sharpened professionally by a shop but then the owner put them back on an now that im looking at it the knifes are fully in the drum an not adjusted out at all . . . . How far should the knife be adjusted out from the drum ?
An the gap between the knife (sharpened edged ) an the chop block is 0.50 . . Is this rite ? An i will hand turn the drum for clearance 
before starting for sure .


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## Buzzsaw22 (Apr 1, 2013)

Steve-Maine said:


> I can send you a copy of an an Asplundh Model JEY manual. should be same adjustments as yours. It id very important that bed knive is perfectly square or your wasting your time. Anybody that grinds chipper knives can grind the bed plate.
> [email protected] Falmouth, me



If you could send me a copy of that manual for that JEY Model that would be really helpful . Thank You


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## CalTreeEquip (Apr 1, 2013)

Lot of words for something so basic.
I'll have to check this tomorrow but if I remember right its like this:

Adjust the bed knife first. The clearance between the drum in bed knife is 7/32 (i think). Use two 7/32 drill bits as a gauge. The adjust the blades to the bed knife. The advertised clearance is 0.030" (again, I think) but I usually get them so they just squeak by. These chippers seem to feed better the closer the clearance is and the chips are finer.


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## pdqdl (Apr 1, 2013)

Yep. Lots of words, hopefully not wasted in an attempt to share understanding.

If I had any experience on that (unknown) model, I would have put up some hard measurements. Even your own depth settings seem rather insecurely stated. I was going to suggest 3/8ths clearance, but that would be a wild guess on an unknown machine.

So...let the reader beware! Be careful, check everything twice, and understand that the value of the info you get here is worth exactly what you paid for it.


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## pdqdl (Apr 1, 2013)

Buzzsaw22 said:


> Yes you are rite there is adjuster screws behind the knifes an when i bought this chipper the own said that they had the knifes sharpened professionally by a shop but then the owner put them back on an now that im looking at it the knifes are fully in the drum an not adjusted out at all . . . . How far should the knife be adjusted out from the drum ?
> An the gap between the knife (sharpened edged ) an the chop block is 0.50 . . Is this rite ? An i will hand turn the drum for clearance
> before starting for sure .



I don't know what you are referring to when you say "chop block". A picture or a better description might help. Would ".50" be 1/2 inch? I am pretty certain that is way too much clearance for most chippers. Try to get that manual, it is probably better than anything you can catch here at AS.

I think you need to read all the posts again, and look at your machine some more. 

Each knife on the drum will have it's own adjuster screws, one on each side.
The bed knife will have it's own adjuster screws, one on each side, in addition to the hold-down bolts.

There may be other adjustable features on the machine that we cannot see in the pictures.


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## CalTreeEquip (Apr 1, 2013)

pdqdl said:


> Yep. Lots of words, hopefully not wasted in an attempt to share understanding.
> 
> If I had any experience on that (unknown) model, I would have put up some hard measurements. Even your own depth settings seem rather insecurely stated. I was going to suggest 3/8ths clearance, but that would be a wild guess on an unknown machine.
> 
> So...let the reader beware! Be careful, check everything twice, and understand that the value of the info you get here is worth exactly what you paid for it.



Like I said, I'll check the manual tomorrow and confirm. Pretty sure those are the right numbers though. I'v done dozens of these chippers.


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## Buzzsaw22 (Apr 3, 2013)

CalTreeEquip said:


> Like I said, I'll check the manual tomorrow and confirm. Pretty sure those are the right numbers though. I'v done dozens of these chippers.



Ok thank you any and all info would really help at this point , Thanx Again Everyone for your help .


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## CalTreeEquip (Apr 3, 2013)

Yes, its 7/32" (.218) clearance between the drum and the edge of the bed knife.
.030 to .035" clearance from the bed knife to the blades.
Again I usually use a .010 gauge for that clearance and sometimes I just eyeball it and make in very close.
Be sure to up the bed knife and block out and turn it to a fresh edge and clean it.
Also pull the adjuster bolt on the knives and clean and grease them. If those suckers get stuck your screwed.
Clean and grease everything. Start over with a new machine, that's my policy.
And don't forget to torque those bolts.


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## pdqdl (Apr 3, 2013)

Yep. Drilling out those adjuster bolts (or any other part of a chipper) really sucks. Been there, done that.

I recommend anti-seize compound before grease, though. It just works better and lasts longer.


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## VA-Sawyer (Apr 5, 2013)

I also prefer Anti-Seize over grease on the adjustment bolts. I use a dial indicator on a magnetic mount to set blades. On a 10" diameter drum, I would start at about .100 inch of blade protrusion above the drum and .030 inch of clearance between the blade and anvil. You can adjust the blade protrusion to control how agressive the feed is. I like to adjust the protrusion so the machine is self feeding without being so agressive it trys to peel skin off my fingers with every branch. I suggest making changes in small increments of no more than .015 inch per change. Blade protrusion is pretty sensitive. 

I use the dial indicator to check bearing slop, drum run-out, blade protrusion, etc. It is also useful for checking for blade creep after a bit of chipping. Like others have said, don't want metal hitting metal under any conditions! 
Use a torque wrench to tighten blade hold down bolts. I also like the Blue Loc-Tite on them.

Good Luck,
Rick


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