chipper: heavier, 1000rpm flywheel better for smaller tractor? WC68, WM-8h, WC88

[orangetree]

Buying a PTO chipper. My rig is on the smaller end of viability with 21.7 pto hp. PTO lift is 1600lbs@2ft aft (also FEL + beet juice in all 4 wheels). My use case is primarily conifer (eg, soft), and mostly small (anything ~4" or larger becomes "firepit" firewood). The large input capacity seems great/necessary to reduce processing of larger branches, tree tops, etc - but I have no ambitions for 6" trees of any sort, and understand my tractor will require slow feeds on larger material anyway.

I am not understanding, *especially* for a ~underpowered use case: wouldn't the following not only chip well but actually be significantly more "kind" to my tractor:

• heavier flywheel: smooths out power demand (higher inertia), might transfer less impact to the PTO & 3-point
• 1000rpm vs 540rpm:
  • because it's belt driven (not direct drive) this should significantly ease wear on my pto drivetrain?
  • and it would have ~4x the inertia (rises with square of speed), even more effective than increasing mass

The common models recommended seem to be woodland mills WC68 and woodmaxx wm-8h. Then there is the WC88 which seems to combine the benefits of both (but is rated to require 50% more hp than the WM8h - ie more than my tractor has) I own implements from both companies, very satisified with quality of both. My pto is rated for both (on the lower end) wm8h/wc68.

• The WM-8h has both a heavier flywheel and belt-driven/1000rpm
  • it also has dual powered infeed and a lift-bar for the infeed rollers
  • but a clunkier design (much longer, and requires rear chute post). This matters for me, I am mostly thinning heavy pine/fir woods for fire (so i'm not driving on trails, but through the trees)
• BUT the WC68 folds (moves/stores smaller) and has easy flywheel access
  • it seems easy access to the flywheel will be very helpful (even ignoring blade access , cutting a lot of small stuff I understand I'll need to get in there to clean things out regularly?)
• enter the wc88 - which is NOT rated for my HP (35hp min) but would seem to combine some benefits of the WM8h (fast/belt slightly heavier flywheel) with the folding, accessible design of the WC68

Questions:

• am I thinking about the "wear on my tractor" correctly here?
• the WM-8h is rated for my tractor but the WC88 is not - they would seem to be nearly identical.
  • Is the WM-8h overly optimistic (understanding limits on larger stuff & feed rate obviously)? What are the downsides to the wc88 on my rig?
• practically speaking, even if the direct drive & mass of the WC68 is worse, would I notice any difference on mostly 4" softwoods with my rig?

Thanks!

 

[sea2summit]

The 1000 vs 540 is based on what you're tractor delivers for PTO RPM, nothing to do with the chipper per say. The flywheel of the chipper will probably have its own tac and recommended RPM probably close to 1200 rpm max.

The heavier flywheel will take some of the shockload off of the PTO and be more efficient overall, I would look there.

Having hydraulic feed with only 21 PTO HP is really going to take a lot of power, I'd look at a gravity feed chipper if I was using it on a tractor that size.

I have the Woodmaxx MX9900 and the difference between a 50 PTO tractor and a 60 PTO tractor is staggering, I was shocked it may double the speed. So moral of the story, PTO HP is still your friend when chipping.

 

[ericm979]

I have a Woodmaxx 8H which I run on a 37hp tractor with 32 hp at the pto. Chipping is one activitity where I wish I had a tractor with more power.

The flywheel intertia might help on a short branch that is too large for the tractor's power but with one more than a foot or so long the chipper will slow. When the chipper is slowed down because the engine can't keep it turning at full speed, the flywheel effect makes it take longer to speed back up.

Belt drive isn't going to make any difference. The belts don't slip and if they did they'd wear quickly. I don't see the chipper wearing the tractor unless you're trying to start the chipper with the tractor engine revved up, which will be hard on the clutch or PTO clutch.

The Woodmaxx WM8H and Woodland Mills WC88 are totally different designs with some common features like an 8" throat, belt drive, and being made in China but designed in North America. Woodmaxx's HP ratings are more optimistic, too much in my opinion.

There's video on youtube of a guy running a WM8H on a 21hp tractor. You can see (well, hear) how much it slows on what look to be fairly small branches.

 

[RalphVa]

If you have any hills you need to take the chipper up/down on, you need to also consider the weight. Our WC46 chipper is just over 500 #, and the weight is felt on the hill behind the house. In my mind the WC68 at 700 # would be too heavy for the B2601 Kubota or would have been on the 2025R JD.

I ran a MacKissic TPH-122 that take up to 3 1/2 inch stuff in the chipper chute for 16 years and a similar Troy Bilt Tomahawk for 10 years before that (a beast to maintain vs. the Mac a dream). The Mac did fine on the 18.5 engine hp JD 4010 (like a 2019E if they made them today). Think I stalled the engine once in 9 years operating it. The JD 2025R and Kubota B2601 just loaf along using the WC46 at 450 PTO rpm and 5 speed on the hydraulic feed (you'd really not want to use the 10 speed as it can really whip some tree parts around at you). Have had the WC46 for a couple of years. Have not rotated the chipper blades yet.

I take along a low lift hydraulic jack in the FEL to raise the input feed roller on the WC46 when it gets stuck. I've read that the Woodmax has something to raise its roller.

Chipping hp requirement only goes up by the square root of the wood diameter. So, your tractor could chip a fairly large diameter tree. Like I said, 18.5 hp is fine for 3 1/2 inches. Your 26 hp tractor could do up to about 7 inches. It would easily take the 8 inch machine at probably half input speed, but I doubt you'd want that much weight back there.

 

[ericm979]

Chipping hp requirement only goes up by the square root of the wood diameter. So, your tractor could chip a fairly large diameter tree. Like I said, 18.5 hp is fine for 3 1/2 inches. Your 26 hp tractor could do up to about 7 inches.

I think you are optimistic here. Chipping larger material takes a lot of power. My 37hp tractor can't chip 7" material, even when it's super easy to machine madrone.

 

[oldballs]

I can't address the physics of this technicality. I'd just say that 7 inches of any tree for a 21 HP PTO is too much. My Kubotas (B2620 & B2650) with 19 HP PTO work well with the WC68. But I don't feed anything larger than 3- 4 inches max thru it. As for hills and/ or woods for toting the thing around and operating.....My place is only moderaately hilly and there are no problems using or moving it around. I try to operate it on as level as possible seating....sometime using a plank to level it up behind the tractor. Setting the hydraulic infeed is important.

 

[orangetree]

I'd just say that 7 inches of any tree for a 21 HP PTO is too much. [...] 19 HP PTO work well with the WC68. But I don't feed anything larger than 3- 4 inches max thru it.

Yes, definitely. I envision the vast majority being 2-3" branch stalks with leaves/needles. No way I would expect my tractor to do well (or at all) on 6,7,8" wood, even if that's softwood.

 

[orangetree]

The 1000 vs 540 is based on what you're tractor delivers for PTO RPM, nothing to do with the chipper per say. The flywheel of the chipper will probably have its own tac and recommended RPM probably close to 1200 rpm max.

As I understand it, the WM-8h and similar have a 2~to~1 belt drive: tractor still operates at 540, pulleys ~double that.

Is this incorrect?

looks correct to me from the pictures: (see much larger lower pulley)

 

[orangetree]

Having hydraulic feed with only 21 PTO HP is really going to take a lot of power, I'd look at a gravity feed chipper if I was using it on a tractor that size.

Yes, it definitely takes power ...

I (anticipate) I'd rather be limited to (say) <= 4" fir or <=3" maple AND have feed, vs add an inch to those practical capacities but have to hand-feed *everything* - the vast majority of what I'd even want to shred fits in the smaller size range.

 

[sea2summit]

As I understand it, the WM-8h and similar have a 2~to~1 belt drive: tractor still operates at 540, pulleys ~double that.

Is this incorrect?

I would assume that is correct, really haven't researched it at all and didn't consider flywheel speed when I purchased.

 

[ericm979]

The 8H flywheel turns at 1150 rpm when the PTO is 540. A little over 2:1

Having owned and used manual "chuck and duck" and hydraulic feed chippers, I would not go back to the manual. The hydraulic feed is safer. Less futzing around to get the material to feed, and when it does it feeds at a controlled rate rather than being sucked in at high speed.

Most manual feed chippers have the chute at a downward angle which means you have to cut limbs short and lift them up and hold them to get them to go down. My 8H's chute is level so I only need to lift the material up to get it in and then lift the other end to get it under the upper roller. Once the rollers grab it I can let go and go get another one.

My manual feed chipper will eject unchipped stubs out the chute hard enough to cause injury. You have to know not to be putting something in before it was completely finished with that branch. With the 8H I can feed in as much as it will take and nothing gets shot back out at me.

My 8H came with a hydraulic speed controller made for a 20 gpm system but the unit is 3 gpm. It had two speeds: fast and slow. It's a known problem with flow control valves that are sized too large. I put a smaller one on and it's now adjustable to any speed as you'd expect. Last I looked the smallest flow control valves of that type readily available in China were 20 gpm. Which is why it was on the unit.

 

[orangetree]

Thanks all for your input.

For me it came down to VC68 vs WC88 - the reason is the WC88 seems very similar to the WM8h (missing dual rollers & lift bar, but has the faster flywheel). Obviously i'm power-limited on spinning up the flywheel, but as above it would SEEM to me that faster speed would still be a huge advantage

Spoke with WoodlandMills, however, and they were adamant that it does not. They said the WMs' owners have ~30 pto HP on their personal tractors, and they specifically said that the wc68, on a small-horsepower tractor, would chip LARGER diameter pieces than the wc68 (on that same small-HP tractor).

I'm not optimizing for tree-size of course, but i suppose I should take this as a reasonable heuristic stating there would being very little, if not negative, functionality improvement bumping up to the wc88 ...

ordered the wc68

Now ... wait ... and wait .... a lovely couple of years we've all had in that respect, huh.

 

[ponytug]

I have the Woodmaxx WM-8H, which I converted from PTO to hydraulic drive. Like @ericm979, I would never go back to manual feed. I find myself setting the infeed speed, putting through like sized branches, and then turning it up or down as the sizes shift. The stubs rattle around between the infeed roller and the chipping wheel and never come back out.

I have about 30HP at the drive, and definitely wish I had twice that, but this gets through all my small stuff for fire reduction, which is what I need. I don't need to send 6" logs through.

I have run through enough brush to sharpen the blades a few times, and the blade switch (flip) process is quick and easy, and Woodmaxx has designed in a rotor lock to make it even easier.

My only complaint is the hydraulic feed tank needs to be really full and level for it to prime. Not a show stopper at all, just an idiosyncrasy. I would buy it again in a heartbeat.

Faster isn't better; as the rotor moves faster, it has more aerodynamic drag, which wastes precious horsepower. Trust the designers to have twiddled the knobs on the various trade offs. I can tell you for certain that high speed on the rotor does not stop stalls on difficult pieces.

All the best,

Peter

 

[RalphVa]

Like I said, think I may have had one (1) stall running the 3 1/2 inch chipper full with the 18.5 engine hp JD 4010 in 9 years on it. This unit did not have much of a flywheel. Could have been instrumental in causing the destruction of the driveshaft Ujoint at 660 hours and 9 years.

Maybe the hydraulic feed takes quite a bit of hp. However the JD 2025R with 24.5 engine hp just loafed along with it running at 450 PTO speed (because don't need that 24.5 hp) with mid setting on the hydraulic feed on the WC46. Never ever had a feeling it was loaded down with a full 4 inch tree being drawn into it.

 

[Whitbread]

I have a Wm8m that I've put about 50 hours on with various power levels. So I have some impressions that might be useful.

Stock 1620 with 22hp at pto, the chipper had no noticeable rpm drop doing 2-"3" oak branches 3-4" green pine. Anything over that and it was working hard and clearly getting near the hp limit.

1620 with turbo added and fuel turned up to somewhere around 25-28 pto hp, much better performance with 3-4" hardwood limbs and 5-6" pine. Can still bog it and stall it if I don't stop the infeed momentarily to let it catch up on big stuff here and there.

On my friends 36pto hp tym 474, took 5" hardwood and 6" pine and barely dropped rpms at all.



My overall bang/buck recommendation would be to get the wm8h and swap out the hydraulic flow valve for a proper gpm rated one. It's always nicer to have the bigger throat dimensions so you trim less branches. As long the knives are kept sharp, on the slowest feed speed you should have no problem doing 4-5" material when necessary. I also very much like the flat chute angle of the woodmaxx units vs the angled wooland mills units.

 

[Erik M]

I have a 60 hp PTO and run the WC88 and think the Woodland Mills are a well engineered unit. The hydraulic infeed can be set to the speed needed by the work. The hinged flywheel cover means it is easy to access the flywheel, and I can drive the tractor into the garage without removing the chute by hinging it open (low door). I have the hitch adapter for mine and pull a trailer for the chips behind the tractor which is very handy. I think you will enjoy your WC68 and find the unit easy to maintain and operate.

 

[oosik]

I think you will do the very best if you simply stay within the recommended limits of the chipper and your tractor. 4" or smaller conifer should be handled well. You will find that a 4" pine - allowed to dry for a year - a harder task.

I run my Wallenstein BX62S with my M6040. I chip only green pines - 6" or less. Works like a dream. I chipped my old, weather hardened apple trees. Now that required a lot more from both the chipper and the tractor.

Flywheel inertia will only last for a brief time. Then it will require brute power from the tractor. My test - chip a 6", green pine that is 30 feet long and 6" on the butt. By the time the chipper is four feet or so up the trunk - is it still chipping at the same speed. If it is slowing down - you are at or near the limit of what the "system" will handle.

I thin my young pine stands almost every spring. 900 to 1200 pines - 6" or less on the butt. Why 6" or less, you ask. You go out and cut a 25' to 30' tall green pine, 6" on the butt and try to man-handle it.

Then imagine this. I go into a stand and fall 40, 60 even 80 young pines. It looks like a giants game of Pick-Up-Sticks. Falling down has become an art form for me. And I'll be 80 years young in a month.

 

[sea2summit]

I think you will do the very best if you simply stay within the recommended limits of the chipper and your tractor. 4" or smaller conifer should be handled well. You will find that a 4" pine - allowed to dry for a year - a harder task.

I run my Wallenstein BX62S with my M6040. I chip only green pines - 6" or less. Works like a dream. I chipped my old, weather hardened apple trees. Now that required a lot more from both the chipper and the tractor.

Flywheel inertia will only last for a brief time. Then it will require brute power from the tractor. My test - chip a 6", green pine that is 30 feet long and 6" on the butt. By the time the chipper is four feet or so up the trunk - is it still chipping at the same speed. If it is slowing down - you are at or near the limit of what the "system" will handle.

I thin my young pine stands almost every spring. 900 to 1200 pines - 6" or less on the butt. Why 6" or less, you ask. You go out and cut a 25' to 30' tall green pine, 6" on the butt and try to man-handle it.

Then imagine this. I go into a stand and fall 40, 60 even 80 young pines. It looks like a giants game of Pick-Up-Sticks. Falling down has become an art form for me. And I'll be 80 years young in a month.

Hope I'm able to thin that many pines when I'm your age!

 

[oosik]

Give you a hint - sea2summit. My chainsaws have gotten smaller. Not much required to cut a 6" green pine. AND this year my son and his friend will help.

This project - thinning the stands - breaks down into three distinct tasks. Identify and fell, drag to a pile, chip. BY FAR - drag to a pile is the most difficult. You try to be smart about the dragging bit but very soon you have a 6" pine and you are climbing over a world of small fallen pines. The old phrase - "bark your shins" has a very real origin.

The act - "falling with grace" - plays into this project also.

 

[Apgamer]

I have a CK2610H and a WM-8H. I used it a large amount this winter and couldn't be happier. I think the CK2610 is more than capable of using the chipper in a reasonable way. I chip 3-4" hardwood and 5-6" pine without any problems. Yes, the feed speed needs to be turned down substantially, but I think the tractor handles it fine. I think the larger displacement motor (1.65 liters) may have something to do with it. Plus, you are not going to be chipping firewood logs.

I think the 1160RPM flywheel is a huge benefit to maintain momentum and store energy. Compared to smaller, non hydraulic feed PTO chippers, these types have a 200+ pound flywheel spinning at twice the RPM. How could that ever be considered a downside? The tractor PTO/clutch has no issue getting it spinning.

My property is covered with piles of chips as a testament to how well the chipper works