Why a stump grinder is worth it it

[5030]

Don't know if I'm a 'professional' or not, I just possess the machine tools and jigs to grind them. I really don't have any pictures available of the surface grinder or the jig I use and the grinder was very expensive to buy, runs on 440-3 and not something anyone in a normal home shop would buy anyway. The grinder is part of the machine and fab shop I own and operate. Grinding chipper knives is a sideline thing. The grinder was not purchased for that. It was purchased for precision grinding of items like die parts. Very heavy, like 6000 pounds and sits on reinforced concrete, 10" thick, like all the machine tools in the shop.

Precision knife grinding always entails removing the human factor and eliminating any manual operation and why regrinding knives is always expensive. The outfit that sells the Wood Max chippers offers a regrinding service and I believe they also charge what I charge or maybe even more. I saw they did when I looked at their website a few years ago. No way can you maintain the correct included angle using a flap disc on a hand grinder and a wood jig will always flex too much in the first place.

The knives have to be jigged in a metal jig ( in my case an angle adjustable steel jig) and ground on a high precision grinder. You have to entirely eliminate any 'human' factor when grinding knives, the human factor causes inaccurate grinding and a flap wheel isn't even close to ideal as most all chipper knives are through hardened tool steel anyway.

When grinding anvils, I jig the anvils vertically against an machinist angle plate and grind them absolutely at 90 degrees to horizontal and my surface grinder has flood coolant as well which is paramount to keeping the knives are anvils cool as overheating any knife or anvil will negatively impact the hardness.

Bought the grinder new, many years ago when I was equipping my machine shop and I believe (If I remember correctly), I paid around 15 grand for it and just getting it in the shop was a chore. Had to move it in the shop on pipe rollers and use machinery jacks to set it. That applied to all the machines I own and remember again, the knife thing for me is just an added value. My employees as well as myself are in the short run machining and fabrication business. The grinder is just one of the machines I own, we have CnC mills, manual mills, hydraulic arbor presses and a few lathes plus welding machines and sawing machines. My expertise is in welding of exotic metals mostly. We do all types of welding here. MIG, TIG, exothermic metal cutting and CNC plasma table cutting for short run production parts as well. Even do O/A welding and brazing if necessary. For me, it's fun. For my employees, it's their livelyhood.

Again, knife and anvil grinding is just a value added sideline for me for when the machine isn't being used for other tasks.

I'd check out the Wood Max outfit as they regrind knives. I have no idea on their requirements or lead times. I just knew they did as I saw it mentioned on their website. If they still do, I have no idea or what their fees are or what their lead times are.

 

[ponytug]

Around here nobody seems to offer the service. I asked several commercial operations and they said that they don't resharpen the blades; they just buy new, flip, and toss. I've donated my old ones to a friend who makes knives and tools. (Hidden chunk of steel did in one set)

Thanks for sharing the set up. I agree that the key to sharpening is removing the human and the flex. I sharpen all my other cutting tools myself (bits, chisels, knives), but not wood chipper blades as I can't match the depth of the grind to a reasonable value. Yes, much as I would love to have a large surface grinder in the shop, it would get used once in a blue moon.

FWIW: does still offer the sharpening service, and I will say that their US steel blades are noticeably more effective than the Chinese blades.

All the best,

Peter

 

[5030]

I might add that if you want your knives ground. I can do it, so long as the surface grinder isn't tied up on other jobs. You would be responsible for shipping both ways and they have to be packaged properly as even when dull, they can still injure a post office employee. Consequently, the cutting edges have to be covered with a couple layers of masking tape and the knives have to be packed in a suitable corrugated cardboard box. You can send them USPS but again, they have to be securely packaged and your cost to regrind and restore the cutting edge is a buck an inch times 2 if both edges are ground and again, you are responsible for shipping both ways. You can contact me at sales@flipmeisters.com or flip@cass.net Anvils are charged by the lineal inch times 2 again as anvils have 2 working edges. So long as the machine isn't running something else, turn around time would be a week.

 

[ponytug]

@5030 Thanks!

 

[5030]

Around here nobody seems to offer the service. I asked several commercial operations and they said that they don't resharpen the blades; they just buy new, flip, and toss. I've donated my old ones to a friend who makes knives and tools. (Hidden chunk of steel did in one set)

Thanks for sharing the set up. I agree that the key to sharpening is removing the human and the flex. I sharpen all my other cutting tools myself (bits, chisels, knives), but not wood chipper blades as I can't match the depth of the grind to a reasonable value. Yes, much as I would love to have a large surface grinder in the shop, it would get used once in a blue moon.

FWIW: does still offer the sharpening service, and I will say that their US steel blades are noticeably more effective than the Chinese blades.

All the best,

Peter

Chipper knives like chainsaw loops are getting more and more expensive to replace as inflation and the cost of the raw materials keeps climbing. Why it's often times much more prudent financially to resharpen rather than toss and replace and when it comes to replacing any of them, the China made ones will always be of lesser quality.

Kind of like buying Chinese replacement carbs for outdoor power equipment. better buy more than one, just in case one is defective.

Far as saw chains are concerned, better price wise to buy a roll of chain and 'make your your own up'. Just not a roll of Chinese chain.

 

[RadarTech]

Do they vibrate enough to damage a tractor?
I know someone who said that would truly destroy a tractor, so he said they were not a good idea…

Thoughts?

 

[sixdogs]

Do they vibrate enough to damage a tractor?
I know someone who said that would truly destroy a tractor, so he said they were not a good idea…

Thoughts?

Not really. I can think of other things like an auger in tough ground that would be way worse. When you get into position to grind, you set the machine on the ground and that stabilizes it.

The depth and speed of the grinding process is controlled by the operator. If you're grinding a normal amount it's a smooth grinding with a little noise but pretty smooth. Sort-of sounds like a big tablesaw.

You can chip a stump quickly so there is no need to hurry. But if you decided to take huge bites, you could get some vibration because it's using the machine incorrectly. Also, if the machine were incorrectly adjusted, the hydraulic flow would not be smooth and that could cause someone to think they bounce around.

I wouldn't do that to my equipment and have zero issues with a stump grinder properly set up and run correctly. It's possible your friend had a bad experience and that's set in his mind forever.


Here's a generic video of a stump grinder

 

[RadarTech]

Not really. I can think of other things like an auger in tough ground that would be way worse. When you get into position to grind, you set the machine on the ground and that stabilizes it.

The depth and speed of the grinding process is controlled by the operator. If you're grinding a normal amount it's a smooth grinding with a little noise but pretty smooth. Sort-of sounds like a big tablesaw.

You can chip a stump quickly so there is no need to hurry. But if you decided to take huge bites, you could get some vibration because it's using the machine incorrectly. Also, if the machine were incorrectly adjusted, the hydraulic flow would not be smooth and that could cause someone to think they bounce around.

I wouldn't do that to my equipment and have zero issues with a stump grinder properly set up and run correctly. It's possible your friend had a bad experience and that's set in his mind forever.


Here's a generic video of a stump grinder

Great! I think he has only rented machines… likely with dull teeth.. that and likely taking to big of a bite is his most likely issue ….
I do remember one sage advice I laughed hard at..
“Never keep the tank full it will go bad”. But wouldn’t that let condensation in the tank occur ?
“That’s wrong”.

SMH…