New GreenTeeth

[Xtra]

Here's some pics of the new Green Teeth shown at the TCIA Hartford expo.

No nuts, they are held in by friction and the pockets are much smaller for less drag. Since they are thinner, an angled head bolt is used (sorta like a lug bolt).

 

[Xtra]

Here's how they recommend sharpening the teeth.
- put the tooth in a drill press
- place a weight on the handle of the press
- connect to a timer and set for a few minutes

 

[John464]

Hey Bob thanks for the pics/info

 

[dtw902]

There is a spring clip on the shaft of the tooth that expands into a groove in the pocket. All it takes is a hammer to tap the tooth down and turn the tooth and tap back up into the pocket.

 

[Dadatwins]

Looks good, smaller pocket should be less weight, that was big problem with greenteeth in my opinion. Are they going to use this new system in all size teeth? Greenteeth recomended the smaller teeth for the small machines but the nuts were an issue, they would wear down and be a pain to get off. This looks like a nice solution.

 

[Xtra]

The worn nut issue is why they changed.

I like the extra weight, more inertia while cutting, but their pocket size causes a lot of drag when going deep in a stump or root chasing.


For my large grinder, 2 months ago I ordered 100 large green teeth and new bolts for my pockets, so it will be a while before I switch.

For my smaller grinder I just ordered 300 1/2" teeth, so it will be sometime before I switch there also.
(btw: I use Leonardi's pin teeth . . . they're great no measuring and they come in hard or soft carbide hardness)

 

[stumpgo]

Thanks xtra - most interesting. I have been exploring cutting systems for some time, and experimenting with green teeth for around a month as a replacement for the Arborplant multi-tip system on my Predator 26.

I work mainly in very tough soil conditions. Plenty of hard stone/pebble and all the buried crap associated with redevelopment sites. I am perhaps the record holder for destroying multi-tip units - approx. 400 in 800 engine hours; and that is with careful use and resharpening where possible.

Some comments on Green Teeth so far:-
(Available in 4 sizes - 500, 700, 900 and 1100. This translates to cutter diameters of approx. 0.5 to 1.1 inches. I have used only 700s and 1100s)

- 700s are not suitable for harsh conditions - too much nut wear plus wear to the cutter holding end of the pockets.

- Weight is a serious consideration. 4 left/right cutter combinations adds approx 50% to the weight of my 19" multi-tip wheel. (Think clutch, brake, head bearing and balance of machine). Reckon I can get that down to about 20-25% when/if I get a new wheel made (slightly thinner and scalloped between pocket stations). With the new system probably a similar weight to the original wheel could be achieved.

- The wheel runs and cuts very smoothly; though fairly precise control of slewing etc is required.

- As if by magic the green teeth seem to produce significantly less spoil (than multi-tip). Requiring less backing out and clearing on larger stumps. (Any churning of the spoil makes no sense with a low powered machine.)

- Using all 3 edges of the cutters is a reasonable expectation. (That is if the pockets have been accurately machined - see later). For all but the smallest of stumps I cut the clean wood with sharp lead cutters then turn to a dull edge for the root zone. Then return to the sharp edge for the clean material of the next stump and so on. Eventually aiming for a uniformally worn cutter before renewing. This reduces the waste when resharpening - which is a breeze compared to Raycos and multi-tip. (Pop into a keyless drill and present the rotating lower edge to the grinding wheel. Like that almost nothing espapes the dust extraction system.) Further I find that subtly grinding the side can reduce the total amount of carbide removed as well as sort out small chips, with no apparent loss of cutting efficiency etc.

- The cutters seem pretty durable.

- I have quality control issues with Green Manaf. Through their UK dealer they have provided some poor brazing on a few cutters as well as some very dodgy pockets (Mainly 700s). The centering of the boring for the cutter bolts has been all over the place. I have one in front of me, and several like it, where the wall thickness on one side is 4.4mm and 2.4mm on the other, which puts the countersinking pretty much right on the outside. Add a little wear in use and I can see, or not see!, a cutter heading off at around 70mph. This is compounded by the countersinking on some cutters being too shallow, so that a cutter cannot seat fully.

- I think xtra's initial post pretty much explains this. A new system is coming, its the last chance to sell the marginal (and dangerous) old style pockets. Ship them abroad, and counter any complaints with a 'the new system is much better' line. I'm complaining, so I should find out.
Out of 4 countersunk pockets I could find only 1 that was spot on. I needed 2 and compromised with one that was 2mm more aggressive. This may not seem very much, and is not noticeable in use; but means the fitted cutter is working in both slew directions, resulting in one of the cutter turning options being lost.

- On the positive side if Greens address the lead rock teeth issue intelligently, as have Sandvik (too many cutters and too much weight to be right for me), then I reckon their new system could be an absolute winner. Cut the clean wood with efficient cutters. which their standard teeth certainly are, then tap out and replace with very serious, less efficient, rock teeth for the root zone.
If they need encouraging I shall be doing my best do so.

- FINALLY, the bonus for those using Greenteeth of size 900 down. Get yourself quickly across to their website where they are selling 'rock teeth' for less than half the price of standard teeth. These are standard teeth but with thicker carbide; thus anyone who sharpens will get a double bonus.
Greens describe these as a NEW product; by that they mean OBSOLETE, no more are to be made. That's marketing for you!

 

[stumpgo]

Apologies - "....This is compounded by the countersinking on some cutters being too shallow, so that a cutter cannot seat fully." Should read that it is the countersinking of the cutter holding boring on the pocket that is too shallow, sp that a cutter cannot seat fully.

 

[Curbside]

Stumpgo

Am I reading you correct that you take the time to change all your cutters in the middle of the stump to do the below grade cutting and then switch them all back to start the next stump.

 

[stumpgo]

Yes, Curbside, that's about half right. I am generally only turning the lead cutters back and forth. Which is 4 with green teeth (2 or 3 minutes) or with multi-tips, change 2 cutters (5 minutes).
If there are a few stumps in the same area, I might well take the clean wood out of all of them; turn the cutters and go round them all again. Might even go round them 3 times! - Absolutely clean wood, getting towards the nasty and finally the terrible bit.

I realise this probably sounds insane to a Canadian/North American. It seems your solution to most problems is more horse-power. For me in little UK it is access first, then making the best of the horse-power that can be got there. Much large urban property is 100-200 years old (with decaying or unwanted trees of that age) and was designed around the wheel barrow. Think walled back yards with a 30 inch gate as the only access, short of being craned over a 3 storey house. With time and extensions it gets worse. Perfectly ordinary for the only access to be through the garage and out of a standard house door at the back.

Principally, I work as a subcontractor to tree, landscape and building firms; and have no/little control over specifications. Generally I work to a foot below grade, for replanting and honey fungus considerations. And quite often much deeper, eg. working alongside a micro-digger to dig footings adjacent to or through a 5ft stump.

The Predator 26 is the top machine for such work. Built on variable width rubber tracks the whole thing is very compact and pulls into a width of 27 inches, weighing 1 ton. In work the cutter head has a 4 ft sweep with a 26hp diesel to power it.

Another UK consideration is PLG (private/light goods), any vehicle with a max gross weight of less than 3.5 tons legally counts as a car, avoiding a whole raft of costly regulations and restrictions that apply to goods vehicles. I fit the Predator and a conventional pedestrian machine (Promark SP16) side by side between the wheel arches of a standard Ford Transit panel van. With all ancillary equipment, but no passengers, it just makes that limit.

Horses for courses

 

[Thor's Hammer]

Stumpgo, have you tried the Sandvic disk? It really has no equal in terms of cutting performance and tooth durability.

 

[Curbside]

Stumpgo

I see what your saying. I agree with Thor's Hammer You should try the Sandvic wheel you won't bother changing teeth. They are the most rugged teeth out there.

I am interested in that little grinder you call a Predator. What is it and where is it made. I searched it and did not find much on it. Is it a real rugged machine? Are they only available on your side of the pond. I've never seen one that is only 26" and carries that kind of horsepower. Might come in real handy here. How does it compare to a Vermeer 252 or a carlton etc in the same size? Do you know the web sight for the manufactuer?

Thanks

 

[John464]

Stumpgo, have you tried the Sandvic disk? It really has no equal in terms of cutting performance and tooth durability.

that may be so, however, Like stumpgo I am hesitant to purchase Sandvik due to the increased rotaional mass(weight) that can and will effect clutch longevity and bearings

The Leonardi M1 system appears to be similar to Sandvik and lighter(lighter than OEM?) Haven't heard from anyone w/ experience in using both systems to see if it cuts just as well

I'm holding off until more feedback is recieved from end users.

 

[Thor's Hammer]

We have a license from Sandvic to build the duradisc and fit their teeth. We dont follow the carlton type disc, we cut a narrow 1/2 inch disc from hardox type steel.
Here is the grinder we build running a 22" duradisc
http://video.google.co.uk/videoplay...l=8&start=0&num=10&so=0&type=search&plindex=1

Heres the predator- A very nice machine, but suffers from falling apartness acording to a lot of users.

 

[stumper63]

Sandvik User

Hi,
I've got 175 hours on a Sandvik wheel on my 252. Had 1400 hours on the clutch when installed, still going strong. Got 2400 on the machine overall. For me, I like the increased rotational mass, it cuts way better than the Vermeer teeth, esp. down in the dirt, it doesn't bog down nearly as fast, and when it does, I know you're not going to believe this, but, it recovers just as fast, if not faster than with the 35lb lighter Vermeer setup. I can't explain it, it's just what I'm experiencing. A loaded Sandvik wheel for the 252 weights 85 lbs, the loaded Vermeer weighed 50 lbs. when I removed it.
New cutter wheel bearings at time of install, no problems yet. Time will tell about premature bearing or clutch failure with the Sandvik wheel, but so far so good, and I LOVE the performance and durability of the teeth.

Stumper63

 

[Curbside]

Thor's Hammer

How have you found the Predator. You say some find it falls apart but how about you guys. Do you know if the machine is available in North America.

 

[stumpgo]

I have not tried the Sandvik wheel. About 18 months ago I looked into it fairly thoroughly; and was impressed. But Sandvik's offering was a total of 24 cutters and a loaded wheel weight of 41kg. That is fully TWICE the weight of the multi-tip wheel. Just on that it was not on. Had I been offered the set up on a thin wheel I reckon I would have gone for it and probably been very happpy. Now I am less sure......I'll explain:-

I've had drilled about as many pocket holding holes in my multi-tip wheel as is possible and tried a variety of mixtures of multi-tip, Rayco type and Green cutters. Within the constraint of balance etc I have tried setting up the left side and right sides of the wheel differently; giving real time comparisons.

With sharp cutters and clean wood all tried options perform about the same. ie in a totally satisfactory way.
This absolutely includes the most extreme option I tried - a total of 4 cutters, 2 on each side of the wheel (Green 1.1 inch diameter). If an abandonded and buried lump of iron work, or similar, is going to be side swiped I'd much rather do that with 2 than 12 cutters. The name of the game then is the cost in time and materials of maintaining sharp cutters for clean wood. For harsh conditions less is best.

Now 1 inch of cut is on the low end of what the 26hp will comfortably pull. I am settling on a total of 8 cutters, 4 each side. All Green Teeth 1100's. With the lead pair on each side being set about 0.8" ahead of the secondary pair. Giving a max cut of just under 2 inches. This set up adds about 50% to the wheel weight and is already adversely affecting the machines balance. In 1 week I expect to have finalised this set-up, and will then be getting a lighter wheel made.

Thanks Xtra for the photo of a semi-automatic sharpening system. I now have one, working on the depth gauge setting rather than a timer. Brilliant, I now no longer need to pretend to be a drill holding statue. Currently using a green wheel, but once I've worked out the best size and profile for the wheel will go diamond. Project currently on hold - I have no blunt cutters left!


Does the Predator fall apart. Yes, with careless use and maintenance. With competant use and maintenance - No.

I bought one of the last pre-production models. It had done 6 months and 100 hours as a demonstrator and hire machine. Coming with 6 months warrantee. This I used extensively, almost entirely putting right careless use and maintenance under its previous owner, the manafacturer. - from a depot that was about to be shut down.

Since then it has just performed with no untoward wear or deterioration. (2 years & 700 hours).
Most of the machine is well designed and generally over-built. Apart from the frame and cutting arm virtually all the bits are standard industrial components. Superb but noisy engine with very good pulling power at reduced revs. (Italian, Lombardini air cooled twin cylinder industrial diesel).
Sight of the wheel is not good. I believe it can now come with wireless remote.

The weaknesses are in the head end.

The head unit itself is threaded to take the 4 holding bolts, which in turn pass through slots in the cutter arm that are used for drive belt tensioning. Quick and dirty with an impact wrench ensures that the threads in the head unit casting will get ***** in no time.
I've recoiled/helicoiled those threads, have a stock of bolts and leave air tools out of it. Problem solved.

The final drive is a toothed belt, cam belt style. They last six months, are very expensive, break with no warning when their condition looks good and are best replaced in a workshop. PIA. I replaced this with a basic triple V nearly a year ago, end of problem; all for less than the price of new toothed belt.

The head bearing lasts a year, I can live with that. Its easy to change and a standard chunk. (I'm told the bearing is different in the those sold now - might be different but no better, I really only know the machine I've got)

The chip guard/screening was crap and expensive. Best used straight away as a template to cut a new one from conveyor belting.

And clearly I have an issue with the teeth. Multi-tips are not suited to hard pebble or really any harsh conditions. A cutting unit comprises 4 rayco like carbide tips compactly arranged into 2 lead and 2 side cutters. http://www.multi-tip.com/ This leaves a handy wide V between the cabide tips on each side to perfectly trap stone. Further, the carbide tapers in thickness away from the tip.
Once a side cutter is broken the whole unit is useless. If a lead cutter is damaged the unit can go into 2nd or 3rd slots, where the lead pair do precisely nothing. I produced more of those than I could use.

Can the Predator be bought in the USA, I don't know. Arborplant does not handle sales, selling is now licensed to ........? Here are contact details as well as outline details on the 50 and 75 models, same concept but different design. http://www.arborplant.co.uk/grinderhire.html

 

[Thor's Hammer]

Stumpgo,
we found exactly the same problem during testing on the toothed polychain. We now fit ours with 4 a section kevlar lined belts.
I have found the sandvic teeth to be fantastic. even when grinding through piles of old bricks and concrete, the wear is minimal. when they wear down, it takes 30 seconds to swap the teeth round to use the other cutting edge.

My opinions on the falling apartness of the predator is based on a few friends / customers who've had them. Mainly the same as you said - poor maintanence and the polybelt are the biggest complaints.

I would be interested to know what the wheel speed on the predator is though.

Heres a good set of pics -
http://www.obmtec.com/Downloads_OBM_Recy/Folders/Predator/Predator 26 EN.pdf

Curbside, no one sells the Predator in the states. With the dollar dropping against the £, you would be paying about $40,000 for a new predator. Our grinders are sold through Top Notch Equipment in MN. early next year we will be releasing a tracked version with radio remote as standard, that will fit through a 29" gate.

 

[stumpgo]

Thor's Hammer

Here's my sum for the wheel speed.

Engine rated at max 2200rpm. Say, 2000rpm under load.

This is geared down by the primary drive by around 0.65
The final drive is 1:1.

This leads to a max working wheel speed of around 1300rpm. On the 19", tip to tip, wheel this translates to a cutter speed of approx. 6,500 ft/min. which is around 75mph. (In the stone zone I expect I am running at 900-1100rpm).

Thats the sum I used for my belt and bearing supplier to work out options for a V belt final drive. I settled for an A section triple V - Pulleys 140 SPA and 3 XPA 2282 belts (£10 each). Theoretically that combination had a bit of slack capacity, and that seems about right, the belts need to be run very tight. The first sign that they need tensioning comes with switching off the wheel when the belts are still cold - as the wheel brake slams in the belts give a short squeal.

Interested to know how you got 4 A section belts in there.

 

[Thor's Hammer]

I think 6500 is close to optimal for carbide cutting in wood. We're running about the same speed with our grinder. Ekka did some good research and clever mods with his kanga grinder to get similar speeds, improved its performance drasticaly.

4 A sections? its a nice snug fit...