Disc vs. Drum Chippers

[John Paul Sanborn]

Nice machine when running talk to me when it is thirty years old
like mine and chips all day long hardly ever needing attention
and can keep ten men busy no waiting in line.
I have just about quit chipping now just load with grapple
let see if you can beat that with your chipper lol I have
come to hate chippers over the years and the only one
I would consider $ well spent is a whole tree with grapple
as I want the machine to work not me!

If you have a grapple truck then the grapple loader would be superfluous. I know a couple of guys with them and they hardly use them because the other loaders are so much more versitile and faster.

Put a remote throttle on the big chipper and the guy in the loader can run the rpm's up and down as needed.

 

[NCTREE]

It is more a product of the hp behind the cutting system then the system it'self. I've used large capacity disks without a problem. Drums will give you more of the more irregular chips then a disk. with sharp knives and proper anvil tolerance equil machines will operate in a similar fashion.

With the new auto feed systems is the hp that important? I would think not. The only difference I could see is that an 85hp will trip the auto much more than say a 125hp.

Talk to the factory reps, it is heavier, needs to be built heavier and costs more to produce. The drum just needs a bigger volume for housing.

It is a Chevy:Ford thing, like a Chevy a drum is cheaper to build up and operate on an hp/size comparison. That was a tough lesson to learn for a young motor head with a 302 way back in '87.

The bandit dealer rep told me that the disc is heavier than the drum so it takes more to get the disc moving which can have more wear anf tear on the engine in the long run. Plus when chipping larger diameter wood and stopping the chipper after finishing that discs can get lodged with chunks of wood which in turn can wear on the clutch and engine too.

 

[alpineman]

Nice machine when running talk to me when it is thirty years old
like mine and chips all day long hardly ever needing attention
and can keep ten men busy no waiting in line.
I have just about quit chipping now just load with grapple
let see if you can beat that with your chipper lol I have
come to hate chippers over the years and the only one
I would consider $ well spent is a whole tree with grapple
as I want the machine to work not me!

Hate chippers??? You must be in an area where you can dump for extremely cheap!! or burn your material??

 

[pdqdl]

There seems to be a lot of conflict over which is heavier: Drum or Disk.

I can clear this up for you; it is a simple matter of understanding the physics. Quit listening to the salesmen; it is not their job to be accurate. Their only purpose is to move the equipment.

A rotating disc with the same weight as a drum chipper, each turning at the same speed, will have more momentum (stored energy) than the drum. This is because the disk has a greater diameter (for an equal weight), and has more mass located at the outer diameter. So...for any given weight, a disk chipper can chip the same size log, using less horsepower, than it's equal weight drum chipper.

Because of it's larger diameter, a disk chipper reaches a higher blade cutting speed per revolution than the drum chippers. Conversely, the disk chipper always has a slower knife velocity near the center than it does at the edges. A drum chipper has the same knife speed across it's width.

Disk chippers also have the advantage of having a more advantageous attack angle on the wood. Because virtually all the wood is cut across the grain at an angle, they use a bit less horsepower to cut the wood, and the chips come off more evenly because they are all cut at the same angle. The drum chipper typically cuts directly across the grain, which requires the most horsepower. As the knife proceeds through the wood, it's attack angle changes until it finishes at close to parallel to the grain. This is why drum chippers tend to produce stringy chips.

Which is the better design? That depends on the engineer that built it! Both designs have certain advantages and disadvantages. Disk chippers tend to be lighter overall and use smaller engines for any given chipping capacity. Drum chippers are better able to take big horsepower and deliver it consistently to the wood. Remember that the disk stores more energy than the drum? That also means that it takes longer to recover from a slow down, and puts more stress on it's engine to get back up to speed.

In the final analysis, the question is not as simple as determining which style is better. That is why both styles are commonly built by all the big manufacturers.

 

[NCTREE]

There seems to be a lot of conflict over which is heavier: Drum or Disk.

I can clear this up for you; it is a simple matter of understanding the physics. Quit listening to the salesmen; it is not their job to be accurate. Their only purpose is to move the equipment.

A rotating disc with the same weight as a drum chipper, each turning at the same speed, will have more momentum (stored energy) than the drum. This is because the disk has a greater diameter (for an equal weight), and has more mass located at the outer diameter. So...for any given weight, a disk chipper can chip the same size log, using less horsepower, than it's equal weight drum chipper.

Because of it's larger diameter, a disk chipper reaches a higher blade cutting speed per revolution than the drum chippers. Conversely, the disk chipper always has a slower knife velocity near the center than it does at the edges. A drum chipper has the same knife speed across it's width.

Disk chippers also have the advantage of having a more advantageous attack angle on the wood. Because virtually all the wood is cut across the grain at an angle, they use a bit less horsepower to cut the wood, and the chips come off more evenly because they are all cut at the same angle. The drum chipper typically cuts directly across the grain, which requires the most horsepower. As the knife proceeds through the wood, it's attack angle changes until it finishes at close to parallel to the grain. This is why drum chippers tend to produce stringy chips.

Which is the better design? That depends on the engineer that built it! Both designs have certain advantages and disadvantages. Disk chippers tend to be lighter overall and use smaller engines for any given chipping capacity. Drum chippers are better able to take big horsepower and deliver it consistently to the wood. Remember that the disk stores more energy than the drum? That also means that it takes longer to recover from a slow down, and puts more stress on it's engine to get back up to speed.

In the final analysis, the question is not as simple as determining which style is better. That is why both styles are commonly built by all the big manufacturers.

Ok I get ya

Now back to my question. With the new auto feed systems does the horsepower really matter that much anymore? I can see with lower hp that the auto feed will trip much more but it still keeps the engine running within its peak performance range thus having less wear and tear on the engine. Im just trying to justify not having to get a larger engine in my chipper. I could be wrong just looking for feedback on this issue.

 

[pdqdl]

I think you are on the right track. Autofeed is definitely the way to get bigger wood chipped with less money.

The autofeed controls allow a smaller machine to chip bigger wood, at less risk to the machine. It protects the machine from bogging down and clogging the chute.

My Bandit 200xp will eat a 12" log with only an 80hp engine. It does stop and go quite a bit while doing it. A 12" drum chipper with a 200hp engine would eat it much faster, but not any more reliably.

I guess it all boils down to how much patience you have. In general, I have found that my little machine generally can out-run a huge crew cutting brush. IMHO, the biggest advantage to the bigger machines is the much larger throat, which allows more of those odd shaped branches to get chipped up without wearing out your men trying to stuff them into the feed wheel.

 

[jg55056]

Suprised no one has talked about fuel consumption. Generally discs will use less fuel because they chip more efficiently. However the new drum chippers are increaseing the size of drum and using the lower half of the drum only. These are becoming more efficent. Look at the new line up of mobark 15 inch chippers. They increased their drum size...............a lot. Drum chippers will eat big wood all day. Try maxing the capacity of a disc and you'll be fighting it all day. I rented a bandit 2290 last year for some landclearing. Talk about a fun chipper! The infeed system was so powerful if it was hooked up to a pickup it would pull it backwards.:msp_smile:

 

[NCTREE]

Suprised no one has talked about fuel consumption. Generally discs will use less fuel because they chip more efficiently. However the new drum chippers are increaseing the size of drum and using the lower half of the drum only. These are becoming more efficent. Look at the new line up of mobark 15 inch chippers. They increased their drum size...............a lot. Drum chippers will eat big wood all day. Try maxing the capacity of a disc and you'll be fighting it all day. I rented a bandit 2290 last year for some landclearing. Talk about a fun chipper! The infeed system was so powerful if it was hooked up to a pickup it would pull it backwards.:msp_smile:

Yes the chipper im demoing tomorrow is the 12" bandit 990xp with an 85hp perkins engine with hydro lift cylinder. This seems like a bad ass chipper for its size. I looked at all the other chippers in its class and nothing comes close. It has a 24" diameter drum compared to the 20" drum on the morbark and vermeer. It also has a relatively large infeed throat at 13'x17" Its a demo unit with less than 50 hrs on it and the price is great, vermeer and morbark can't even come close to the price. It has a factory 1 year warranty on the machine and a 5 year warranty on the engine and axle. I have a feeling this is going to be the chipper for me.

It's good to know other guys are running lower hp engines in there machines with little problems like pdqdl. In my situation with the amount of pruning I do compare to removals is about half, so I think this machine will be more than enough for me.

 

[pdqdl]

I got curious about the the weight & horsepower comparisons between disk & drum chippers, so I did some analysis.

I sucked some info off the websites at Vermeer & Bandit, and I made a spreadsheet and did some analysis. I can certainly see why there are differing opinions on the topic, as there are many different models with widely dissimilar traits.

Download & read:

 

[pdqdl]

My little spreadsheets reveal a few conclusions, to which I hope some of you will contribute or criticize.

1. When you evaluate disk vs drum to see which is heavier, it appears that for any given capacity, neither style can be said to be significantly lighter or heavier than the other. It could be argued, however, that some models of drum chipper are built lighter than most disk chippers, since there are more large capacity drum chippers on the top of the list. Also, it is rather obvious that Vermeer is lighter than Bandit, and that smaller chippers generally have a lower ratio of weight to capacity than the larger chippers.

2. When you evaluate disk vs drum to see which is built lighter for any given horsepower, the drum chippers are lighter. More horses, less weight.

3. When you evaluate disk vs drum to see which requires fewer horses to chip any given capacity, the table is mostly loaded at the top with disk chippers, and heavily weighted at the bottom with drum chippers.

4. Ol' Rope has been claiming that he likes the chuck-n-duck best. He may have some keen insight, since the only manual feed chipper on the chart was consistently near the top of the chart for each type of sorting. Overall, I would have to agree that it outperforms all other chippers with respect to capacity, horsepower required, and light to tow. Probably cheaper per inch of capacity, too!

********************************************************************
I would like to mention that when I was collecting data, I always selected the lowest horsepower available. Some of the Bandit machines on these tables might really be underpowered dogs; the Vermeer units did not list multiple engine options.

 

[Bigus Termitius]

The right tool for the right job. All these chippers have their place in the industry when properly employed. Having had and run all three, a disk, a drum, and a chuck n duck,(I know it's a drum too, but it is its own animal) I like all three for their respective advantages.

Rope is right on with most of his points with a chuck n duck. I want one....as a backup mostly. However I have seen where they lack, and while it seems more productive in some situations, it's just busy work sometimes. Things go well when it's all cut or shaped right, and for its relative size and capacity, it's very productive and cost effective. Setting them up a few times, I can get good chips, or go for production, but the chips are not landscape quality. Harder to get someone to take, or buy them, they take up more space, but the larger chips can have their uses. They also often eat more than they can handle leading to taking the time to clear the shoot, which is at least easy enough. I especially like the long term durability aspect.

I’ve abused the crap out of them, and visa versa, but I’ll take my licks all day with a grin. Most people will pass on that. I would always ask newcomers if they remember all the stuff in their life that they "got away with." They’d say, “ Yeah, sure, why?” I’d then welcome them to their first day of reckoning.

I have a midsized disk, and it’s alright. The aspects have been outlined very well in this thread, but to me, it’s not much more than a safer, more user friendly, chuck n duck in too many respects. Good chips though.

I had a Vermeer 1400 with a winch at my disposal for a couple years and the production/effort ratio, all things considered, was awesome. Sure, more things to go wrong, but those things working together made it all right. I talked the company into letting me keep a chuck n duck in the wing for when it did go down, which really wasn’t very often. When it did and we went back to the chuck n duck until I got parts and time, the difference was night and day.

Vermeer is right down the road an hour or so, very convenient for me, so I’m likely to go with one soon, but I wanted to point out that I’m really impressed with one thing I saw on the bandit website that is especially relevant to the conversion. Makes me want to see one in action and consider purchase. And that is the design of the 1390, for example. And I quote from their website:

As with all Bandit hand-fed drum-style chippers (excluding the Model 990XP), the 1390XP comes equipped with a large 37-inch diameter drum. The Bandit drum is nearly 15 inches larger in diameter than most competitive chippers ranging from 12-inch to 15-inch capacity. The larger drum allows for material to be chipped on the bottom half, with the grain of the wood. This will reduce fuel consumption, vibration, and require less horsepower to chip larger diameter material. A larger diameter drum also turns slower than a smaller drum, which increases torque and provides a smoother, more efficient chipping action. The picture below shows how the Bandit drum chips a 14-inch diameter log with the grain on the bottom half, compared to a competitive drum which chips material on the top half, across the grain.

I’m interested; dealers are so far away though. This larger drum seems to be trying to capture the best of both worlds in a sense. Anyone been around this unit? Own or owned one?

 

[NCTREE]

My little spreadsheets reveal a few conclusions, to which I hope some of you will contribute or criticize.

1. When you evaluate disk vs drum to see which is heavier, it appears that for any given capacity, neither style can be said to be significantly lighter or heavier than the other. It could be argued, however, that some models of drum chipper are built lighter than most disk chippers, since there are more large capacity drum chippers on the top of the list. Also, it is rather obvious that Vermeer is lighter than Bandit, and that smaller chippers generally have a lower ratio of weight to capacity than the larger chippers.

2. When you evaluate disk vs drum to see which is built lighter for any given horsepower, the drum chippers are lighter. More horses, less weight.

3. When you evaluate disk vs drum to see which requires fewer horses to chip any given capacity, the table is mostly loaded at the top with disk chippers, and heavily weighted at the bottom with drum chippers.

4. Ol' Rope has been claiming that he likes the chuck-n-duck best. He may have some keen insight, since the only manual feed chipper on the chart was consistently near the top of the chart for each type of sorting. Overall, I would have to agree that it outperforms all other chippers with respect to capacity, horsepower required, and light to tow. Probably cheaper per inch of capacity, too![/U]

********************************************************************
I would like to mention that when I was collecting data, I always selected the lowest horsepower available. Some of the Bandit machines on these tables might really be underpowered dogs; the Vermeer units did not list multiple engine options.

I agree that that the chuck n duck will chip larger capacity for the weight and hp ratio, although I wood like to see it compared to other models as far as "feed rate per minute." I noticed with my chuck n duck it will take larger wood and chip it at faster rates but you can't throw in an 8"x 6' piece of wood an expect it to take it. Usually has to cut into a couple of short pieces. That take a lot more time.

 

[NCTREE]

The right tool for the right job. All these chippers have their place in the industry when properly employed. Having had and run all three, a disk, a drum, and a chuck n duck,(I know it's a drum too, but it is its own animal) I like all three for their respective advantages.

Rope is right on with most of his points with a chuck n duck. I want one....as a backup mostly. However I have seen where they lack, and while it seems more productive in some situations, it's just busy work sometimes. Things go well when it's all cut or shaped right, and for its relative size and capacity, it's very productive and cost effective. Setting them up a few times, I can get good chips, or go for production, but the chips are not landscape quality. Harder to get someone to take, or buy them, they take up more space, but the larger chips can have their uses. They also often eat more than they can handle leading to taking the time to clear the shoot, which is at least easy enough. I especially like the long term durability aspect.

I’ve abused the crap out of them, and visa versa, but I’ll take my licks all day with a grin. Most people will pass on that. I would always ask newcomers if they remember all the stuff in their life that they "got away with." They’d say, “ Yeah, sure, why?” I’d then welcome them to their first day of reckoning.

I have a midsized disk, and it’s alright. The aspects have been outlined very well in this thread, but to me, it’s not much more than a safer, more user friendly, chuck n duck in too many respects. Good chips though.

I had a Vermeer 1400 with a winch at my disposal for a couple years and the production/effort ratio, all things considered, was awesome. Sure, more things to go wrong, but those things working together made it all right. I talked the company into letting me keep a chuck n duck in the wing for when it did go down, which really wasn’t very often. When it did and we went back to the chuck n duck until I got parts and time, the difference was night and day.

Vermeer is right down the road an hour or so, very convenient for me, so I’m likely to go with one soon, but I wanted to point out that I’m really impressed with one thing I saw on the bandit website that is especially relevant to the conversion. Makes me want to see one in action and consider purchase. And that is the design of the 1390, for example. And I quote from their website:

As with all Bandit hand-fed drum-style chippers (excluding the Model 990XP), the 1390XP comes equipped with a large 37-inch diameter drum. The Bandit drum is nearly 15 inches larger in diameter than most competitive chippers ranging from 12-inch to 15-inch capacity. The larger drum allows for material to be chipped on the bottom half, with the grain of the wood. This will reduce fuel consumption, vibration, and require less horsepower to chip larger diameter material. A larger diameter drum also turns slower than a smaller drum, which increases torque and provides a smoother, more efficient chipping action. The picture below shows how the Bandit drum chips a 14-inch diameter log with the grain on the bottom half, compared to a competitive drum which chips material on the top half, across the grain.

I’m interested; dealers are so far away though. This larger drum seems to be trying to capture the best of both worlds in a sense. Anyone been around this unit? Own or owned one?

Thats what I picked up on the Bandit drum chippers. Even the 990xp has a 24" drum compared to it's 12" counterparts which are running 20" drums. I could see that being a factor in chipping efficiency.

 

[pdqdl]

Thanks Bigus.

I saw that note at Bandit, but didn't choose to bring it up.

In the final comparison (geometrically), a drum IS a disk, there is just a mathematical difference on the thickness. What really counts in the chippers is the angle of attack relative to the wood and where the knives are mounted. Bandit has just made a really wide disk chipper with the knives mounted to the outside perimeter of the disk instead of the face.

 

[beowulf343]

I got curious about the the weight & horsepower comparisons between disk & drum chippers, so I did some analysis.

I sucked some info off the websites at Vermeer & Bandit, and I made a spreadsheet and did some analysis. I can certainly see why there are differing opinions on the topic, as there are many different models with widely dissimilar traits.

Thanks pdqdl, i never really looked at the comparisons between chippers, just usually run what i'm given.

I will admit though, my 1990 with the 275 jd is the best chipper i've ever run.:msp_wub:

 

[jg55056]

:agree2:

 

[Bigus Termitius]

Thats what I picked up on the Bandit drum chippers. Even the 990xp has a 24" drum compared to it's 12" counterparts which are running 20" drums. I could see that being a factor in chipping efficiency.

I noticed that, and should have made a note of it. And I imagine that the relation of that 24" drum to the wood is still in a better position as well. I'm interested in your demo experience with this unit as well.

 

[NCTREE]

I noticed that, and should have made a note of it. And I imagine that the relation of that 24" drum to the wood is still in a better position as well. I'm interested in your demo experience with this unit as well.

I demoed the 990xp on Thursday and I was impressed with it's speed and consistancy. I threw some 10" logs thru it and the chip consistancy stayed pretty much the same. Their were a couple of larger chipps but nothing that would really make a difference.

I bought the chipper and will be getting it delivered on Monday.

 

[Bigus Termitius]

I demoed the 990xp on Thursday and I was impressed with it's speed and consistancy. I threw some 10" logs thru it and the chip consistancy stayed pretty much the same. Their were a couple of larger chipps but nothing that would really make a difference.

I bought the chipper and will be getting it delivered on Monday.

Congrats are certainly in order.