Why does dirt dull a chain?

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Spinny

New Member
Dec 26, 2012
83
We all know that dirt dulls chainsaw chains but what is the science behind it? Dirt is soft, wood is much harder, why does dirt instantly make a chain dull?
 

basswidow

Minister of Fire
Oct 17, 2008
1,316
Milton GA
It just does. I guess if you were to take a microscopic look to dirt, you'd find many smaller particals of rock like granite and quartz and though small, bound to dull a chain pronto.

When used to scrounge construction sites where they dragged logs thru the mud, I was constantly having to sharpen.
 
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Spinny

New Member
Dec 26, 2012
83
I also ask because I run a millroom and I wonder if dirty rough lumber dulls planer blades to the same degree it does chainsaw chains.???
 

Ralphie Boy

Minister of Fire
Feb 12, 2012
1,165
Rabbit Hash, Kentucky
Dirt is an abrasive containing many elements, as mentioned by basswidow, harder than a chain or planer blade. I would think it would dull a planer blade fairly quickly, but maybe not as fast as a chain because the planer blade is a different, much harder alloy. I would think dirt from different areas would dull at different rates, depending on the mineral content of the soil in a given area.
 

JP11

Minister of Fire
May 15, 2011
1,452
Central Maine
RPMs of the chain are REALLY fast.

Dirt is the same as sandpaper.. in fact usually really gritty sandpaper.

Doesn't take long with that little edge on that little tooth.

JP
 

tsquini

Minister of Fire
Jan 8, 2009
707
North Shore, MA
Wood dulls my chain too. Wood is a consistent density and smooth. Typically, I'll hit dirt when sawing wood. Ripping sand and rocks through a small space jerks the chain through the wood. The slight hesitation and pull on the chain again creates dull spots. They only get worse with use.
 

Backwoods Savage

Minister of Fire
Feb 14, 2007
27,812
Michigan
I also ask because I run a millroom and I wonder if dirty rough lumber dulls planer blades to the same degree it does chainsaw chains.???
Yes, but perhaps not as fast. That dirty lumber no doubt just has some loose dirt on it but not like hitting the ground with a saw chain. Have you ever watched anyone milling lumber? If the log has been drug or dropped in some dirt, they put a de-barker on. Not so much to remove the bark but to remove the dirt before the saw hits it.
 

Spinny

New Member
Dec 26, 2012
83
Yes, but perhaps not as fast. That dirty lumber no doubt just has some loose dirt on it but not like hitting the ground with a saw chain. Have you ever watched anyone milling lumber? If the log has been drug or dropped in some dirt, they put a de-barker on. Not so much to remove the bark but to remove the dirt before the saw hits it.
Interesting.
 

dmmoss51

Feeling the Heat
Oct 28, 2013
355
Michigan
dirt is made up of a mixture of organics - dead and rotting plant and animal parts and inorganics - small bits of minerals ie rocks. If you ran you chainsaw against a rock you wouldn't guess why it was dull. Why would dirt be different?
 

Backwoods Savage

Minister of Fire
Feb 14, 2007
27,812
Michigan
It also can have different effects depending upon what kind of soil it is. For example, sand is more coarse than loam, etc. But really no matter, if you hit the dirt, sharpen the chain.
 

rwhite

Minister of Fire
Nov 8, 2011
1,612
North Central Idaho
Dirt is not softer than wood. Although there is a great amount of organic matter, dirt is just rocks that have aged a bit longer. The geologic makeup determines the content but it is basically still rock (just smaller).
 
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CenterTree

Minister of Fire
Sep 15, 2008
1,045
SouthWest-Central PA
I can understand why dirt dulls a chain,,,,

but to me the real mystery is how the heck does GRASS dull a mower blade??
_g:confused:
 
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CenterTree

Minister of Fire
Sep 15, 2008
1,045
SouthWest-Central PA
Many years ago, when I first started using a chainsaw, I haphazardly would run the bar into the ground on a lot of cuts. Never thinking it was doing any harm, I was young and stupid.

Was always frustrated that I had dull chains. As I got older (and more educated) I soon realized my mistake. Now I never let the chain hit the dirt. (well, almost never)
.;)
 

Spinny

New Member
Dec 26, 2012
83
Many years ago, when I first started using a chainsaw, I haphazardly would run the bar into the ground on a lot of cuts. Never thinking it was doing any harm, I was young and stupid.

Was always frustrated that I had dull chains. As I got older (and more educated) I soon realized my mistake. Now I never let the chain hit the dirt. (well, almost never)
.;)
I think all of us who are self taught in this area learn that the hard way through experience.
 

Bigg_Redd

Minister of Fire
Oct 19, 2008
4,153
Shelton, WA
We all know that dirt dulls chainsaw chains but what is the science behind it? Dirt is soft, wood is much harder, why does dirt instantly make a chain dull?

Your premises are incorrect - dirt is composed of very hard bits (tiny rocks, sand, ect) in addition to the organic bits, and it is those very hard bits that dull chains.
 

Thistle

Minister of Fire
Dec 16, 2010
4,205
Central IA
I also ask because I run a millroom and I wonder if dirty rough lumber dulls planer blades to the same degree it does chainsaw chains.???
Yes it does.Circular saw blades,band saw blades,any cutting edge.Old paint,varnish & glue will have the same affect,sometimes more severely.
 

Paulywalnut

Minister of Fire
Nov 29, 2012
2,659
Kennett Square, PA
Why does a shaving blade get dull? If you put a small amount of dirt in a glass of water, spin it around
and fine sift it. A lot of small stones and sand. Enemy of the chainsaw.
 

BurnIt13

Minister of Fire
Jun 10, 2010
623
Central MA
Many years ago, when I first started using a chainsaw, I haphazardly would run the bar into the ground on a lot of cuts. Never thinking it was doing any harm, I was young and stupid.
Sometimes you don't have to be young to be stupid. When I moved into my house 6ish years ago we had a burning party. There were some overgrown shrubs, plenty of crap in the woods, plenty of saplings, and some small trees that needed to be taken down.

Well my father in law wanted to help so he borrowed his friends brand new chain saw. After I cut down the trees (with my own chain saw) and moved the rounds out of the way....he wanted to show me an easy way to get rid of stumps.

He dug a little bit around each tree and fired up his buddies chain saw. Plunged it into the earth near the roots and begun cutting through the roots. Then he started cutting up saplings. It got to the point that he couldn't even cut a twig before he stopped and wondered what was wrong. Meanwhile my dad and I are shaking our heads.

He goes to his truck and brings out a cordless drill with a circular file in it and starts running it through what was left of the chain. Yup. And not the file you or I would use, but just a generic rat tail file. But wait...It gets worse.

He brought his own gas too. Filled her up and went back at it. 30 seconds later the saw quits. You guessed it. Gasoline straight from the pump.

Did I mention he never put any bar oil in the brand new chainsaw???

So in about 30 minutes he destroyed a chain, burnt up a bar, and seized the engine of his buddies brand new chain saw. I don't remember what model saw it was, but it was a Stihl. He and his friend don't talk anymore.

You don't need to be young to be stupid.
 
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NH_Wood

Minister of Fire
Dec 24, 2009
2,602
southern NH
Ahh....in-laws! That's a great (bad) story and is why I now avoid letting people borrow my saws - always return in worse shape - especially the chain, but I'd be super pi$$ed if someone ran straight gas in my saws - they are like family. Cheers!
 

Backwoods Savage

Minister of Fire
Feb 14, 2007
27,812
Michigan
I can understand why dirt dulls a chain,,,,

but to me the real mystery is how the heck does GRASS dull a mower blade??
_g:confused:
That mower blade spinning does stir up some dirt too. Regardless, whenever you cut anything there is friction and any blade will dull in time. Otherwise there would be no market for all those files. ;)
 

BrianN

Feeling the Heat
Aug 30, 2012
285
Central BC
I also ask because I run a millroom and I wonder if dirty rough lumber dulls planer blades to the same degree it does chainsaw chains.???
Yes, dirt will dull, and some times destroy planer blades/heads. I work in a planer mill, and am very careful to not put dirty wood through. Makes every ones life easier.
So basically. Dirt, soil, rocks, anything not wood, should not be cut by a chainsaw or planer, if at all possible.
 

Bocephous

Member
Oct 16, 2012
45
Smiley, NEPA
If you are of a mind to do so, take a handful of dirt and rub it on a metal or glass surface you don't care about. Then do the same with a handful of sawdust. The dirt will probably produce swirls on the metal or glass, and the sawdust shouldn't.
 

HDRock

Minister of Fire
Oct 25, 2012
2,239
Grand Blanc, Mi
I also ask because I run a millroom and I wonder if dirty rough lumber dulls planer blades to the same degree it does chainsaw chains.???
Dirty lumber well dull your planner blades at light speed
 
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