wood chipper/shredder mod to increase chip size

[GeneV]

Guys, anybody done such a mod? I got a Dirty Hand Tools 3" chipper/shredder, but the chip size it makes are tiny, almost fit for compost. I'd live to increase chip size, make it more usable for mulching. Is there usually an adjustment for the anvils in there? I don't know much about the internal workings of these.

 

[5030]

Most anvils mount with a set of bed bolts and can be adjusted in and out. Normal setting for clearance is the thickness of a credit card (anvil to knife clearance) so you might want to check that. the closer the anvil is to the knife, the smaller chip is produced.

 

[s219]

Dedicated chippers usually have a gap adjustment for knives and anvil, but wider gaps take more power to make the cut, so you may find the chipper bogs down. Normally there is a spec for gap and you are supposed to set to that.

A unit with shredding capability will have a different type of cutting arrangement and may not be something you can change. They may use hammers and anvils. They are a different beast than a pure chipper. Normally you can’t tweak the output size of a shredder.

 

[GeneV]

Thanks for the info guys. Yeh it is a chipper/shredder, and it already does bog down when I stick a big branch in there. So I learned to not just jam it in.

 

[oosik]

I have a Wallenstein BX62S. It has a specific gap - knife blades to anvil. My chip size - half to one third the size of a playing card and about two times as thick as a playing card.

 

[bigtiller]

If you could purchase a screen for the shredder that has larger holes, it would increase the size of the chips. Or maybe you can remove the screen and drill some of the holes out larger.

 

[Captain Dirty]

As s219 pointed out wider gaps (for larger chips) take more power. With around 6 hp your chipper will be hard pressed to shave chips off the end of a 3" branch, especially if is a dried, slow growing hardwood (like apple or lilac). The operator's manual notes:

• Large, hard, dried tree branches that resist chipping can be processed by rotating them as you alternately insert and retract them. (Effectively reducing the diameter.)
• Material conditions vary, sometimes exceeding the capacity of the equipment. If the material to be chipped is extremely hard, kicks back forcefully when being fed into the chipper inlet, or cannot be easily controlled, remove
  the material immediately and set it aside. Do not attempt to process these materials.

Know and respect the limitations of the equipment you have. I am given to understand that Valby made or makes machines with easy to adjust chip size provisions costing on the order of 10X Dirty Hands.

 

[oosik]

If you have a screen on the chipper discharge chute - take it off. That should increase chip size. I would not recommend increasing the distance between the knife and anvil. It could put an excessive load on the chipper.

When I upgraded my tractor - I wanted to upgrade the chipper also. I had a Wallenstein BX42S. I looked at a Valby. They make some superior units. But the nearest dealer is in Montana. I went with my Wally BX62S and have had no regrets.

I even considered the Wally BX92S. Then I had a stroke of realism. It's all I can manage - drag a 25 to 30 foot long pine that is 6" on the butt. There is NO WAY I would have been able to drag a 32 to 35 foot pine that was 9" on the butt. Since I will fell 800 to 1100 small pines - I have no time to fool around with a system that is beyond my abilities.

My spring felling/chipping sessions usually last a month or more. Or until I get so beat up from dragging to a pile or falling that I simply quit. Finish off this annual project in the late fall.

Yes - falling down is, unfortunately, a part of thinning my stands. After I thin a stand of small pines - it looks like a giants game of Pick-Up-Sticks.

 

[5030]

Increasing the distance between the anvil and the knife won't impact the ability to chip or present an excessive strain on the chipper. It will however cause it to string chips if the gap is too wide.

 

[GeneV]

Hey guys, yeh thx. I don't see a screen in the discharge, no. This chipper does start to bog down if I force feed it 3" branches, but I'm wise to it's tricks at this point so just pull back on the branch and let it recover. I figure if increasing knife/anvil gap makes that issue slightly worse, it's fine, I could deal.

BUT, 5030 you bring an interesting point about that possibly making wood strings instead of chips, I see what you mean there. Then again, if S219 is right and there's nothing I could adjust in there anyways coz it's a chipper/shredder, well that's the end of that idea anyways. I'll just have to tear in there and see what's up, I'll report back if there's any progress.

 

[GeneV]

Where exactly would this screen be at the discharge, like what's the function of it? Should I be able to see it immediately, or do I have to take apart that discharge housing to get to it?

 

[bigtiller]

Where exactly would this screen be at the discharge, like what's the function of it? Should I be able to see it immediately, or do I have to take apart that discharge housing to get to it?

After looking at your owners manual, I don't think it has a screen. It looks like the "rubber discharge deflector" shown on page 7 does the work of a screen.

It also says the shredder is limited to .5" in size. So basically, leaves only.

 

[GeneV]

After looking at your owners manual, I don't think it has a screen. It looks like the "rubber discharge deflector" shown on page 7 does the work of a screen.

It also says the shredder is limited to .5" in size. So basically, leaves only.

Mine's slightly different, I got an adjustable steel deflector on mine.

So I think I get the function of the screen, correct me if I'm wrong. It holds bigger chunks in so that they could go through the teeth again til they're small enough to pass through the screen. Wonder if removing my deflector would increase chip size, I'll try that.

I don't use this thing for nothing other than branches, but I do have a use for the shredder on top. Branches that have a curved or thick end which keeps it from going all the way through the chipper tube, I shove that end in the shredder...gnaws it off.

 

[OldPaint]

Your chipper output is actually into the same chamber as the shredder on the engine side of the flywheel. The knives cut chunks off the end of the branches you're feeding which go through the slots in the flywheel, and wind up on the same side as where you feed the shredder. The J-hammers are beating the chips up just like they would anything you put in the hopper.

Mine (a 17 year old Murray) is a little different. It uses flails at the outer edge of the flywheel (at a 90 degree angle from the knives) which pass through the screen/baffle that the others are talking about. That baffle is removable for larger chips, but they're really not much larger and instead, I get a lot of long twigs from brush, too. I have a lot of ironwood, hackberry, elm, and birch, and all will clog the little Murray up pretty quick with the stringy bark if I don't take the baffle out.

Most of the chip size will be determined by the amount the knife edge sticks through the flywheel. The gap between the knives and the anvil is mostly just to keep the knives from hitting the anvil which is where the stick is pushed while the knife is chopping a chunk off. But, if you increase that gap, the knife will have a harder time shearing off dryer wood. It simply won't cut as well. The closer the anvil is to the blades, the better they'll cut. Until it gets too close and the knives hit it. The anvil on small chippers like these usually isn't adjustable, and is usually built into the chipper inlet chute. The angle of the stick to the flywheel will affect chip size some as well as it will cut closer with the grain as the angle decreases. But, since the chips go into the shredder chamber before coming out they're gonna get chopped up more by the J-flails.

I don't use my little Murray for chipping anymore because of the severe beating it gives my hands as well as having to cut the brush up more. But the shredder's still useful for rechipping the output from my WC-68 chipper if I want compost filler. I feed it with a pitch fork and don't get the high frequency violent vibrations to my hands feeding the shredder. It is especially unkind with dry brush.

 

[DMW]

Just so everybody knows this is the chipper/shredder being discussed. It is only a residential unit, It's 3" capacity is not the same as the Wallenstein BXM32

 

[GeneV]

Just so everybody knows this is the chipper/shredder being discussed. It is only a residential unit, It's 3" capacity is not the same as the Wallenstein BXM32

Yep, that's the one, except different discharge deflector.

 

[oosik]

FWIW - there is a definite size difference with my BX62S when chipping green pines or dry pines. Green pines chip bigger - dry pines chip smaller.

 

[RalphVa]

Guys, anybody done such a mod? I got a Dirty Hand Tools 3" chipper/shredder, but the chip size it makes are tiny, almost fit for compost. I'd live to increase chip size, make it more usable for mulching. Is there usually an adjustment for the anvils in there? I don't know much about the internal workings of these.

Most have a bed plate. Just adjust it to be farther away from the blade.

 

[5030]

Most have a bed plate. Just adjust it to be farther away from the blade.

Called an anvil Ralph, not a bed plate...

 

[joecdeere]

increasing the gap only leads to poor chipping performance, excessive strain on the knives, quick dulling of the edge, the only true way on a chipper to increase the chip size is to increase the material input speed. If you think of a pair of scissors, how poorly they cut if loose or if there is a gap in the blades. If the gap is large enough, they won’t even cut. I own a Vermeer chipper, and I can slow the feed down to almost make sawdust, or speed it up and make inch or more chips.