stumpgrinder rpm

kimtree · 19th November 2007, 02:01 AM

does anyone know what rpm their stumpgrinder has at the grinding wheel
on my grinder am trying to work out if faster than 2500 rpm is better

Ekka · 19th November 2007, 02:08 AM

What stump grinder you got?

what engine?

What pulley sizes?

What dia cutter wheel?

I can tell you I did a lot of work in this area getting my Kanga to cut better.

Most engines will do around 3500rpm and maybe 3000rpm under load.

On a cutter wheel around 500mm dia you want the wheel doing around 1700rpm ... working on engine doing around 3200RPM

Now the Kanga was doing stupid speed, cutter wheel was way to fast and more like dust was coming off rather than chip ... also less torque.

Now the larger Rayco machines etc the cutter wheel only does around 1200rpm to 1400rpm but they are bigger dia wheels so the circumference speed is a lot higher.

There's a preferred speed, just imagine a lathe and you go too fast or too slow with the chuck. For wood the cutting speed is around 8000ft/min

kimtree · 19th November 2007, 02:16 AM

Quote:

Originally Posted by Ekka

What stump grinder you got?

what engine?

What pulley sizes?

What dia cutter wheel?

I can tell you I did a lot of work in this area getting my Kanga to cut better.

Most engines will do around 3500rpm and maybe 3000rpm under load.

On a cutter wheel around 500mm dia you want the wheel doing around 1700rpm ... working on engine doing around 3200RPM

Now the Kanga was doing stupid speed, cutter wheel was way to fast and more like dust was coming off rather than chip ... also less torque.

Now the larger Rayco machines etc the cutter wheel only does around 1200rpm to 1400rpm but they are bigger dia wheels so the circumference speed is a lot higher.

There's a preferred speed, just imagine a lathe and you go too fast or too slow with the chuck. For wood the cutting speed is around 8000ft/min

mines a laski 27hp when i got it it was doing 1580 rpm by changeing some pulleys i got 2100 and it definatly cut better then i discover the motor was only doing 3250 got that to 3600rpm now the wheel flys thru stumps at 2580

kimtree · 19th November 2007, 03:06 AM

i have watched the video on your kanga mods,its very good like all of your other vids,ive have utilised some of your ideas on the laski. its not too bad a machine now.
any other lucky laski owners out there who have fiddled with their machine

Ekka · 19th November 2007, 03:29 AM

What's the dia of the wheel though? Also consider where the teeth are as they stick out a bit further, so should measure the dia to the tips of the teeth ...

... sounds too fast me, you'd be losing a lot of torque and getting a lot of dust.

The kanga used to run 125mm drive pulley onto 155mm cutter head pulley, using 3200rpm at the engine gave around 2500rpm at the cutter wheel, was bad!

Now cutter wheel is doing around 1800rpm as it cuts much better. I changed the drive pulley to 95mm dia ... could go less to 90mm dia and would be better.

I think to the teeth tips was around 550mm dia but dont hold me to that as been a while now. Turning speeds say 12,000ft/min tops for softwood but some hard woods down to 6000ft/min.

What's a chainsaw chain run at, around 2500ft/min to 5000ft/min but it's not tungsten carbide.

Concrete cutter saw runs 5000ft/min

garyhyland60 · 20th May 2008, 03:34 AM

Quote:

Originally Posted by kimtree

i have watched the video on your kanga mods,its very good like all of your other vids,ive have utilised some of your ideas on the laski. its not too bad a machine now.
any other lucky laski owners out there who have fiddled with their machine

hi i have a 27 hp laski could you tell me which pulleys you changed and what sizes i have standard set up and any improvment would be appreiated

TreeDimensional · 20th May 2008, 06:08 AM

Another consideration is what kind of stumps you are grinding. We prefer to grind poplar and spruce stumps when they are frozen solid. They can be ground at other times, but tend to pull and tear rather than cut. We have two stumpers, a 630 and an SC 130 Vermeer. The 130 has a very small diameter wheel, and runs super fast. Believe it or not, it cuts better than the larger (hp) machine in these conditions.

The easiest stumps to cut are the hardest wood, and for my area the hardest wood is ash. We whiz through these stumps in no time flat, but a similar sized poplar or spruce (unfrozen) would take twice the time.

As Ekka pointed out, it is ALL about horsepower (torque), hell they could have propelled the Titanic with a 350 Chev engine, IF they wanted the historic voyage to last forever. In retrospect, it DID!

kimtree · 21st May 2008, 04:23 AM

Quote:

Originally Posted by garyhyland60

hi i have a 27 hp laski could you tell me which pulleys you changed and what sizes i have standard set up and any improvment would be appreiated

Get a multi tip wheel system for starters.I changed the upper and cutter wheel pulley on mine to taperlock 3 belts instead of 2 belts because no matter how i run it i couldnt get the belts to stop slipping and constantly having to tighten them on that machine is a pia.Now it runs much better.I've got to say that the standard cutter wheel is crap compared to a multitip.What really prompted me to change cutting heads was that 2 pocket bolts sheared off[separate occaisions] and threw the whole thing out of whack,it seems that laski uses a 1/2 bolt instead of 5/8 and different pocket hole centres than superteeth so you have to buy theres instead
Pulley sizes 170-3-2517x if you change to these pulleys you have to change the guard
200-3-2517x
Also if you weld a 90degree bend on to the exhaust it stops the belt cover from getting too hot[Ekkas idea}hope this helps

Ekka · 21st May 2008, 04:37 AM

I just fitted new electronic to my machine, the coil and transistor box things shit themselves.

Also fitted a brand new carby coz the ole one pissed me off too much.

Well, those things must have been stuffed for some time coz it goes like a BAT OUT OF HELL now.

garyhyland60 · 23rd May 2008, 09:55 PM

Quote:

Originally Posted by kimtree

Get a multi tip wheel system for starters.I changed the upper and cutter wheel pulley on mine to taperlock 3 belts instead of 2 belts because no matter how i run it i couldnt get the belts to stop slipping and constantly having to tighten them on that machine is a pia.Now it runs much better.I've got to say that the standard cutter wheel is crap compared to a multitip.What really prompted me to change cutting heads was that 2 pocket bolts sheared off[separate occaisions] and threw the whole thing out of whack,it seems that laski uses a 1/2 bolt instead of 5/8 and different pocket hole centres than superteeth so you have to buy theres instead
Pulley sizes 170-3-2517x if you change to these pulleys you have to change the guard
200-3-2517x
Also if you weld a 90degree bend on to the exhaust it stops the belt cover from getting too hot[Ekkas idea}hope this helps

thankyou for your reply g hyland

19th November 2007, 02:01 AM	#1 (permalink)
kimtree Semi-mature vigorous tree Join Date: May 2007 Location: Kununurra WA Posts: 91	stumpgrinder rpm does anyone know what rpm their stumpgrinder has at the grinding wheel on my grinder am trying to work out if faster than 2500 rpm is better

19th November 2007, 02:08 AM	#2 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 6,943	Re: stumpgrinder rpm What stump grinder you got? what engine? What pulley sizes? What dia cutter wheel? I can tell you I did a lot of work in this area getting my Kanga to cut better. Most engines will do around 3500rpm and maybe 3000rpm under load. On a cutter wheel around 500mm dia you want the wheel doing around 1700rpm ... working on engine doing around 3200RPM Now the Kanga was doing stupid speed, cutter wheel was way to fast and more like dust was coming off rather than chip ... also less torque. Now the larger Rayco machines etc the cutter wheel only does around 1200rpm to 1400rpm but they are bigger dia wheels so the circumference speed is a lot higher. There's a preferred speed, just imagine a lathe and you go too fast or too slow with the chuck. For wood the cutting speed is around 8000ft/min __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

19th November 2007, 03:29 AM	#5 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 6,943	Re: stumpgrinder rpm What's the dia of the wheel though? Also consider where the teeth are as they stick out a bit further, so should measure the dia to the tips of the teeth ... ... sounds too fast me, you'd be losing a lot of torque and getting a lot of dust. The kanga used to run 125mm drive pulley onto 155mm cutter head pulley, using 3200rpm at the engine gave around 2500rpm at the cutter wheel, was bad! Now cutter wheel is doing around 1800rpm as it cuts much better. I changed the drive pulley to 95mm dia ... could go less to 90mm dia and would be better. I think to the teeth tips was around 550mm dia but dont hold me to that as been a while now. Turning speeds say 12,000ft/min tops for softwood but some hard woods down to 6000ft/min. What's a chainsaw chain run at, around 2500ft/min to 5000ft/min but it's not tungsten carbide. Concrete cutter saw runs 5000ft/min __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

20th May 2008, 06:08 AM	#7 (permalink)
TreeDimensional Banned Join Date: Feb 2007 Location: Canada Posts: 381	Re: stumpgrinder rpm Another consideration is what kind of stumps you are grinding. We prefer to grind poplar and spruce stumps when they are frozen solid. They can be ground at other times, but tend to pull and tear rather than cut. We have two stumpers, a 630 and an SC 130 Vermeer. The 130 has a very small diameter wheel, and runs super fast. Believe it or not, it cuts better than the larger (hp) machine in these conditions. The easiest stumps to cut are the hardest wood, and for my area the hardest wood is ash. We whiz through these stumps in no time flat, but a similar sized poplar or spruce (unfrozen) would take twice the time. As Ekka pointed out, it is ALL about horsepower (torque), hell they could have propelled the Titanic with a 350 Chev engine, IF they wanted the historic voyage to last forever. In retrospect, it DID!

21st May 2008, 04:37 AM	#9 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 6,943	Re: stumpgrinder rpm I just fitted new electronic to my machine, the coil and transistor box things shit themselves. Also fitted a brand new carby coz the ole one pissed me off too much. Well, those things must have been stuffed for some time coz it goes like a BAT OUT OF HELL now. __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

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