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Saw does not draw itselt into cut

Started by mpuste, June 28, 2010, 01:00:41 PM

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mpuste

I have a Stihl MS280 with RMC3 chain (.325 pitch) that does not draw itself into the wood while cutting.  When I touch the bar to the wood the saw makes sawdust and shavings until I apply pressure after which nice chips will result.  For reference, I have a 021 with PMC3 chain (.375 pitch) that feeds itself into the wood with little pressure.  The end result is that the 021 is much less fatiguing to use.

I sharpen both chains by hand using a round files and Stihl file guides and the depth gauges on both are set at .025 inches.  I've been fiddling with the chain on the 280 for several months and just can't get it to cut like the 021.  Setting the depth gauges a little lower (.025 + couple file strokes) has helped but not eliminated the problem.  Any other suggestions?

Thanks.

jteneyck

Try measuring the depth gages with a straight edge and feeler gages.  As the tooth gets shorter the depth gage actually needs to be set lower than when it's new, so even if it was supposed to be 0.025 inches new it might need to be 0.040 when the tooth is half gone.  I think Carlton's website has a discussion on this.  Anyway, it noticed that the RCM3 chains didn't cut so well either on my MS290 after I sharpened it.  When I checked the depth gages they were more like 0.010" using a straight edge across adjacent teeth and feeler gages.  After I reground them to an honest 0.025" (more like 0.030") it cuts great again.  I also found that Oregon's depth gage file guide does not really lower them 0.025" as printed on the thing, at least not the way I measure.  Something to consider, and reason enough to verify with your own measurements. 

GASoline71

Could also be that the 280 is spinnin' the chain a little faster that the 021.  Saw chain won't "self feed" right from the get go.  Especially on more powerful saws.  You need to add some pressure to get it to cut.  Then you'll get that "sweet spot" where the saw and chain is doing all the work, and you,re simply guiding it down.

Try a loop of RMC instead of the RMC3.  The raker design is different.  The RMC3 is basically "safety" chain... or Stihl's idear of a low kickback chain.  The rakers have a slope to them and are set a little higher.  Regular RMC will toss chips right from the get go. 

If you don't want to stray away from the RMC3... then make sure it is sharp, and check your raker height.

Gary
\"...if ya mess with the bull... ya gets the horn.\"

mpuste

Thanks for the feedback.  Unfortunately, (or perhaps fortunately) the problem is now academic.  I was at my Stihl dealer yesterday and he had an MS 361 in stock.  I've read good things about the 361 on this and other forums and I was finding myself cutting larger trees with the 280 than I originally expected so I traded the 280 for the 361.

Gary, regarding the low-kickback versus standard chain, I had a similar thought so I purchased both RSC and RSC3 chain with the 361 so that I can experiment.

Jteneyck, thanks for the tip regarding feeler gauges.  I also have the Oregon depth gauge and agree it seems a bit crude.  I'll  check it with feeler gauges.

Rocky_J

Your problem has everything to do with the chain and nothing to do with the powerhead. You might be able to pass off that excuse to the old lady as to why you needed to buy a new saw but it won't fly here.  :D If you run the same chain on the new saw and file it the same way then you will have the same problem.

Al_Smith

It's all how you sharpen it no matter who made the chain .

I have no idea about Stihl chain numbers .However the most important thing no matter if it's chisel,semi or chipper is a good working corner .This is where the side and top plate transition .

If for what ever reason this corner gets rounded off from the side plate it will not cut worth a hoot .It has to be square in regard to the side plate which is what does the cutting .The top plate just clears the chip .

BTW ,most if not all cutters have a built in back angle on the tooth .In other words as the tooth gets filed back it gets shorter .As such from the front edge of the tooth to the depth gauge does not change .If it's 25 thou on a new tooth it will be 25 thou when it's worn out .

40 or so thou might be a grand plan on a 120 cc race saw but not so good on a working saw of 70 cc.Makes for a danged jerky chain .Even on 1/2" chipper used on torquey old gear drives it's only 35 thou .

Ed

Quote from: Rocky_J on June 29, 2010, 09:11:18 PM
Your problem has everything to do with the chain and nothing to do with the powerhead. You might be able to pass off that excuse to the old lady as to why you needed to buy a new saw but it won't fly here.  :D If you run the same chain on the new saw and file it the same way then you will have the same problem.

Now that there's funny as . True as 'ell, but still funny.

Ed

JohnG28

Well Id say you did good grabbing the 361.  I swapped out the RSC3 for RSC shortly after I bought mine, and am happy I did.  With clean wood it really cuts nice, but with not so clean wood the RMC semi-chisel is good.  I have a couple Stihl brand and WoodlandPro of each type and like them.  Use a file guide and make sure your filing to the proper angle a spec. for the chain.  For Stilhs chain I like the 13/64" they say to use.  Some say a regular 7/32" is fine but I think the 13/64" gives me better results.  Good luck with the new saw, keep that chain sharp and youll love it.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

JohnG28

Another thing to consider also with the RSC3 chain is that the bumper link in front of the raker may need to be filed too to keep the proper clearance.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Kevin

Are you using the bucking spikes?
.025" should be plenty on the depth gauges but if the top of the cutters are rounded from being in the dirt then the cutters need to be filed back beyond the damage.

mpuste

If bucking spikes = dogs then I typically only use them when the nose of the bar is buried in a log.  Otherwise I prefer to let the saw feed itself through the cut -- easier on both of us.  I'll have to pay closer attention to the top plate next time.  I thought they were all sharp but it makes sense that if the depth gauge is correct then the only other part of the cutter that would impact the chains "bite" is the top plate.

Al_Smith

Probabley the best thing you can do for yourself is to spend 8 bucks and buy an Oregon file guide which comes with one file and the instructions for use .Use the correct file size and you shouldn't have any problems .

Some people catch on to free hand filing quickly and some never do but anyone can do a good job using a file guide .

HolmenTree

Many people new to hand filing don't put enough "hook" in the cutters side plates. Sometimes their lazy filing have more backslope then hook. Especially while filing the right hand cutters.
Years ago new sawchain off the roll or out of the box had to be filed or reground for it to cut properly. Now today Oregon and Stihl put alot more aggressive "hook" and a better edge on their  cutters.
A little hook [not too much] makes a better self feeding chain. I remember years ago the forestry company I worked for gave us fallers Oregon file guide holders to use. I ended up putting  toothpicks between both ends of the file and file guide holder to get a better hook in the cutter. The guides setting wasn't aggressive enough.
Willard.
Making a living with a saw since age 16.

Al_Smith

 I kind of agree with you a tad bit . However the guide will give the less experianced filer at least the proper angle and depth . Certain little tricks like opening the gullet up a tad bit and compound angles can be learned later .

Everybody that operates a chainsaw should be able to at least file a standard chain .The only way this will ever happen is to do it .

mpuste

Quote from: Al_Smith on July 01, 2010, 02:21:14 PM
Probabley the best thing you can do for yourself is to spend 8 bucks and buy an Oregon file guide which comes with one file and the instructions for use .Use the correct file size and you shouldn't have any problems .

Some people catch on to free hand filing quickly and some never do but anyone can do a good job using a file guide .

When I bought the 021 around 10 years ago I also purchased a Stihl file guide and have hand filed since then.  The only exception is when I hit stone or metal and then the chain goes to the dealer for grinding.  I've been happy with the results.  It's a good feeling when the saw feeds itself into the wood and produces a shower of rectangular chips.  I bought the 280 (with a different style cutter) around two years ago and did the same thing with satisfactory results until this past winter when for some reason the saw stopped feeding itself into the wood.  Now I am searching for explanations from others who have had a similar experience or who have a more advanced understanding of cutter geometry/sharpening.

jteneyck

Madsen's website has a very good discussion on sharpening.  I believe it's at

www.madsens1.com

mpuste

Great web site.  Lots of interesting information about saws in general.  Thanks for sharing.  The Carlton web site you recommended earlier also had an informative handbook on saw chains.  I did not realize that each cutter pivots (rocks back) as it enters the cut.  That explains why you cannot just file down the depth gauges but must also maintain the original gauge angle.  Never heard that one explained before.

Thanks again.

northern

I find it a good idea to bring your chains in to be sharpend on a grinder every so often (maybe once a year) depending on how much cutting and hand filing you do.  It helps bring them back to "spec" so to speak.  For about $5, it can save a lot of frustation.

John Mc

Quote from: northern on July 07, 2010, 07:41:25 AM
I find it a good idea to bring your chains in to be sharpend on a grinder every so often (maybe once a year) depending on how much cutting and hand filing you do.  It helps bring them back to "spec" so to speak.  For about $5, it can save a lot of frustration.

If you take it to someone who knows what they are doing, that can help. Your typical local hardware store with a chain grinder may not have someone trained on how to do this properly (or the one person that knows it well might not be on duty when you bring it in). If it's not done properly, it can cause you more trouble than it solves.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

northern

Quote from: John Mc on July 07, 2010, 08:34:54 AM
Quote from: northern on July 07, 2010, 07:41:25 AM
I find it a good idea to bring your chains in to be sharpend on a grinder every so often (maybe once a year) depending on how much cutting and hand filing you do.  It helps bring them back to "spec" so to speak.  For about $5, it can save a lot of frustration.

If you take it to someone who knows what they are doing, that can help. Your typical local hardware store with a chain grinder may not have someone trained on how to do this properly (or the one person that knows it well might not be on duty when you bring it in). If it's not done properly, it can cause you more trouble than it solves.

True enough.  I should have specified a reputable place.  A saw dealer, or sharpening specialty shop, or something of the sort.

John Mc

Quote from: northern on July 07, 2010, 08:54:12 AM
True enough.  I should have specified a reputable place.  A saw dealer, or sharpening specialty shop, or something of the sort.

I hope I didn't come across as picking at your post. I was just trying to give a heads up that not all grinder operators are created equal.

If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

northern

Quote from: John Mc on July 07, 2010, 11:04:54 AM
Quote from: northern on July 07, 2010, 08:54:12 AM
True enough.  I should have specified a reputable place.  A saw dealer, or sharpening specialty shop, or something of the sort.

I hope I didn't come across as picking at your post. I was just trying to give a heads up that not all grinder operators are created equal.


Not at all!  You made a good point, that I missed.  Thank you.

mpuste

I should have included a link to the Carlton chain handbook I referenced in my last post but was in a hurry.
http://www.sawchain.com/images/complete%20book.pdf

Page 5 describes the dynamics of saw chain during a cut and page 19 describes the "progressive method" of setting depth gauge height.  The short story is that Carlton does not recommend a constant differential height between the cutter top plate and depth gauge (such as .025 inches) but one that progressively increases as the cutter tooth shortens.  Judging from the number of fixed height gauges on the market I suspect this is not universally accepted.

mpuste

Quote from: northern on July 07, 2010, 07:41:25 AM
I find it a good idea to bring your chains in to be sharpend on a grinder every so often (maybe once a year) depending on how much cutting and hand filing you do.  It helps bring them back to "spec" so to speak.  For about $5, it can save a lot of frustation.

Agree.  I just like to know why a problem is occurring, even if I am unable or unwilling to fix it myself.
Personal issue...

Al_Smith

 :D Oh my gents you're making mountains out of mole hills on this chain stuff now .

I personally have not had a chain ground in probabley 35 years but some how I get by without it . I'm not the only one either .

Now maybe if you were a western faller on the slopes of Washington state or Idaho and using square ground chain that might be a valid reason for  grinder .Round ground any thing, chisel, semi chisel, chipper file real easily . No need for a grinder but you have to learn to file and the only way that will ever happen is to do it ,so get with it . 8)

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