Why does PMN cut better than RSC3?

[xhibit4]

I have been very disappointed with how quickly RSC3 chain becomes dull. Have cut down & bucked 8 80'-100' red oak and ash with the same results. the chains do not last long. The chains are sharpened on a Stihl grinder at the dealer.

Today I inadvertently did an odd comparision. 20" dia. red oak felled on Sunday, 018 16" bar with PMN thin kerf made 15 cuts which actually was more because I had to cut from the other side to get through the whole log, so 15 full and 15 small, with a couple that were 30" because of transition to triple main branches. The chain surprisingly still had some life left to it and gradually started to dull.

Next up was my MS361 25" ES bar with the RSC3, the first 3 cuts were fine, saw did the work, the rest were me digging the bumber spikes into the bark and arcing the bar down to cut and then moving the bumber spikes down to do it again. Really it was obvious the chain was considerably duller after the 3rd cut.

Both chains end up contacting the ground although I go slow at the end of each cut to avoid this as much as possible, and both chains are anti kickback and anti-vibration (green label).

I can't imagine the kerf .043" PMN/.050" RSC3 could make up for the difference.
Also, "micro" (PMN/RMC) is better for dirty wood but have seen many posts about "Square ground chisel" (RS) being only for clean wood and rounded ground chisel (RSC3) is for dirty, so some ground contact is expected.

I've spoken to the dealer on more than one occasion and they have no explanation. I am switching to RSC but can't imagine it will make that much of a difference over RSC3.

Opinions are appreciated, I have a 120' 30" red oak to cut up in the next weekand would like to spend more time cutting and less time changing/sharpening blades.

 

[Jtheo]

I am running 33RSC in oak with no problem with the chain getting dull fast.

You will have to keep it out of the dirt though.

And be safe, 33RSC is not low kickback, but if you have experience you know that.

 

[ntsarborist]

all i can see the problem with the chains is either dirty wood or coming in contact with the ground or hitting steel. dont let your chain within an inch from the ground unless you cant help it. the wind from the chain coming close to the ground can pick up dirt therefor you get a dull chain. a new chain will last a long time without it being sharpened if it is taken care of.

 

[woodlotguy]

Did your dealer adjust your depth gauges accordinly.Sometimes this gets overlooked.Itried to cut a tree in a fire situation and I think I could have knawed through it faster.Turns out that was the problem.

 

[woodchux]

Sounds like you might need some carbide tip chains... :greenchainsaw:

 

[ntsarborist]

Sounds like you might need some carbide tip chains... :greenchainsaw:

speaking of. how good are those carbide chains. never used one but heard they are expensive. have a groundie that likes to run the saw into everything and could use one but was never sure how good they are. thought about buying a cement saw for him. cutting into his pay for new chains dont work

 

[woodchux]

They are expensive and slower cutting... but great for flushing stumps and dirty logs.

 

[xhibit4]

Thanks for the input everybody, looks like I need to be more careful about dirt contact.

Unfortunately I had the same problem with a freshly sharpened RSC3 on the first cut into what was left of the still standing red oak. I cut a 14" piece that was 23" in dia. so I still had 2" of unused bar. I know you do not get the same bite when cutting horizontally but the chain really struggled from the git go, and it had nothing to do with the weight of the log as that does not come into play until way into the cut and I had wedged it when it came time.

I addressed grinder set-up with the Stihl dealer when I picked the chain up and they said this was a common chain for them to sharpen so you would assume they had the grinder set with the proper parameters.

At this point either they did not have the angles set right or RSC3 is not meant for Red Oak. I'll have to tactfully talk to the dealer again about the grinder set-up and ask to speak to the person who actually does the sharpening.

My concern is when I switch over to RSC I'll have the same problem if they are not settiing up their grinder properly, what do you all think?

 

[treemandan]

Thanks for the input everybody, looks like I need to be more careful about dirt contact.

Unfortunately I had the same problem with a freshly sharpened RSC3 on the first cut into what was left of the still standing red oak. I cut a 14" piece that was 23" in dia. so I still had 2" of unused bar. I know you do not get the same bite when cutting horizontally but the chain really struggled from the git go, and it had nothing to do with the weight of the log as that does not come into play until way into the cut and I had wedged it when it came time.

I addressed grinder set-up with the Stihl dealer when I picked the chain up and they said this was a common chain for them to sharpen so you would assume they had the grinder set with the proper parameters.

At this point either they did not have the angles set right or RSC3 is not meant for Red Oak. I'll have to tactfully talk to the dealer again about the grinder set-up and ask to speak to the person who actually does the sharpening.

My concern is when I switch over to RSC I'll have the same problem if they are not settiing up their grinder properly, what do you all think?

Well, since you asked: I think you are beating the crap outta your chains, not paying attention, hitting the dirt and whatnot. I don't think you have figured out how to sharpen either. Don't feel bad, its not as easy as it looks. Neither is sharping a chain.
You should post some pictures of the chains... and your bar too as they go hand in hand. That would be the best place to start. There was a time when I had no idea either.
Yes, the shop knows, round chain on the small saws, not-round chain on the big saws. Its a no- brainer but there are some really aggressive types who put the square stuff on the 20's, I seen it.

By the way, I am in Phoenixville. What shop you go to? I usually have the big chains done for me if they are real bad and sometimes when I get them back they aren't that great. As you sharpen a chain the grinder wheel wears...

 

[xhibit4]

I get the "watch out for the dirt" advice, I guess I did not realize how little dirt it takes to dull a chain but this last chain was freshly ground and never touched dirt, it should have cut right through that oak. I use CDI in Collegville and am going to order a bench mount filing tool so I can start to learn how to do my own sharpenings.

 

[treemandan]

I get the "watch out for the dirt" advice, I guess I did not realize how little dirt it takes to dull a chain but this last chain was freshly ground and never touched dirt, it should have cut right through that oak. I use CDI in Collegville and am going to order a bench mount filing tool so I can start to learn how to do my own sharpenings.

For hand filing I used Pferd guides.

 

[bagaman]

The best thing I ever did was to learn how to properly sharpen a chain by hand. I feel it is far superior too a grind. I will grind only if the chain is seriously beat up, and even then I will fine tune it it with a file. Dont forget the rakers, probably the most overlooked part of sharpening a chain.

 

[Maldeney]

The best thing I ever did was to learn how to properly sharpen a chain by hand. I feel it is far superior too a grind. I will grind only if the chain is seriously beat up, and even then I will fine tune it it with a file. Dont forget the rakers, probably the most overlooked part of sharpening a chain.

I agree with the hand filing. I have not had much experience with chain grinders but after you file a chain or two you will start to see the results of what you are doing. Before I bought my saw 6 months ago I had never filed a chain..... First time was kinda ugly! It wasn't long until I decided that you don't have to file your guts out to get it sharp and not alot of pressure is required either. Take 10-15 minutes with your chain on your bar after you have cut and think you are dulled out, and put a file to it and see if you can make a difference.


On another thought.... Are your saws tuned right? If you are making three cuts then noticing a change, that would be about the time everything is warming up and your mix will change a little. Maybe not.

 

[ntsarborist]

one other thought. the bars on your saws. how old are they aand how often are they used. look at them and feel the edges. if they feel like there bowed out you might have to grind the bar down. just a trick on how to save a junk bar.

 

[Brushwacker]

Up in the limbs I would guess is where you mostly cut with the 018 and the wood is usually much cleaner then the lower trunk + you probably cleared the ground far enough with no or little contact. Lower parts of the tree are just exposed to more dirt, dust etc.,from wind,animals and this and that and some dirt ends up embedded ine bark or wood usually in very small amounts but it affects the edge of a chain. Bumping into the dirt affects it a lot more.

 

[Tim Carroll]

You could try switching to RM chain over the RS. I have found it holds an edge longer than the RS. It is not as fast cutting but will handle dirt a little better but it's always best to avoid the dirt as much as posible.