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questions and help with ripping chain

Started by ethanbrush, April 10, 2014, 11:17:19 PM

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ethanbrush

So I got into sawing up some 34" wide maple slabs  today, 7' long.  ITs an old sperber mill run by an 075, woodsman pro 3/8 ripping chain, sharpening with the granberg rotary grinder and jig.  I think I am not sharpening correctly but i am not sure what I am doing wrong.  Here is what is happening:  After I sharpen, it seems real "bite-y".  It cuts fast but just seems maybe too aggresive and doesnt cut that smooth and then it seems to dull quick.  I only get one slab per sharpen, sometimes less. Is this typical?  I havent milled hardwood at this width before so maybe this isnt out of line...what would you guys expect for sharpening interval for this?  Would a different grind perhaps hold an edge longer?  Right now I am doing perpendicular to the width of the bar and 10 degree angle.  I put machinists blue on the teeth before I grind so I can see clearly what I am doing so i think I am doing a good job and getting the whole cutter sharp and I am using the wax on the stone.  Rakers started out at .030 and are down to .025 or so now so that is in the ballpark from what I read.  Another big question I have is how does the height that the top of the stone/file is above the cutter effect things?  I usually see 10-20% stated in sharpening instructions  but I dont have a spec on that for this chain.  Any recommendations on that measurement?

It seemed to cut real nice the first cut (I had sharpened it, not factory), but went downhill from there.  the first cut wasnt full width though.  I am thinking of maybe trying a granberg chain.  When I lowered the rakers on this chain  I did it by hand with a file and there seemed to be a lot of inconsistency in their hardness.  Any recommendations of comments would be appreciated.  Despite the troubles, and all the time sharpening, We did get 5 cut.  I try to post a picture.  I dont think Ill ever flinch or complain about sharpening my 18" bar now after all the sharpening I did today!
Timber Harvester 30HTD25
Stihl 075 w/ Sperber 36" CSM
Husky 550XP
Uniforest 45M
New Holland TC-45

ethanbrush

Timber Harvester 30HTD25
Stihl 075 w/ Sperber 36" CSM
Husky 550XP
Uniforest 45M
New Holland TC-45

scsmith42

Ethan, what you describe is similar to what I would expect from a chainsaw mill on a log that size.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

backwoods sawyer

Over filing your rakers will make a chain grabbby.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

VT-Woodchuck

I found that there was a difference in brands of chain. The Stihl was by far the best - it stayed sharper longer. I always used a gauge when filing the rakers. The 075's slower rpm is great for chainsaw milling. Your pictures make me want to get back at it! ;D

Hilltop366

A thought that may or may not apply to this situation.

If your taking too much metal off the under side of the cutting edge it will cut aggressively but because the tooth is so thin at the edge it might not stay sharp long.

ethanbrush

Quote from: Hilltop366 on April 11, 2014, 01:01:03 PM
A thought that may or may not apply to this situation.

If your taking too much metal off the under side of the cutting edge it will cut aggressively but because the tooth is so thin at the edge it might not stay sharp long.

I think that may be what is going on.  I should raise the stone to get less of a "Beak" shape.  I think that is the side plate angle.
Timber Harvester 30HTD25
Stihl 075 w/ Sperber 36" CSM
Husky 550XP
Uniforest 45M
New Holland TC-45

jclvsall

Great question!  I have spent quite a bit of time in the jungles of the south pacific milling some huge and hard as a rock stuff with a chainsaw so I can relate to your issue. 

Several questions.

#1 How are you filing your rakers?  If you are not using a guide and flat file you should be.  They all need to be exactly the same.  The "bitey" symptom could very well be that the rakers are different.  You say the rakers are at .025ish  I usually took mine to .035 with good results.

#2 Are you biased with your decision to file at 10*?  I ask this because I was.  I was very skeptical to take the advice on this website http://www.sawmillchainsaws.com/sawchains.htm to file them back to 0*.  You read that right! 0*!  I decided to try it out one day in the jungle and was amazed how well it worked.   

#3 Are all your teeth the same size?  This question relates to the length of the cutting tooth.  If some are filed more aggressively than others and are shorter they will actually be different heights.  It will get real bitey if you have some tall and some short teeth.  It seems a waste but you really need to take every tooth down to the size of the smallest one on the chain!

#4 does your saw bar lay horizontal or does it stand up vertical when you are cutting?  I had some oiler problems when we were cutting big logs with the bar vertical.  The bar and chain were heating and dulling quickly. 


   This is Benson training a worker to run the mill in some Whitewood.

   This is Benson cutting 25mm planks for our kitchen table.

   This is some Merbau we cut for our solar panel array framework. Merbau has a janka hardness of 1925! Killer stuff to cut.   Hickory is only around 1820.  Hard maple is about 1450.    You can see how smooth the 0* teeth cut.  BTW the nail is to check the angle of the sun so my boys could rotate the frame to keep the sun @ 90* to the panels.  I took this pic to show them they were slacking!  The shadow was almost off the wood!  boys

GREAT looking crotch planks by the way!

Brian



Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well armed lamb contesting the vote.  Ben Franklin

Seaman

Every thing above! I found a full comp chain WAY too grabby, super skip works much better for me when cutting 24in and wider. The carlton file-o-plate is perfect for rakers, more on that in some of the Lucas mill post. It is essential the rakers be alike, otherwise you have tall and short cutters.
I need to look back thru some old post to see about the beak angle, you are on to something there.
Beautiful wood, I love slabbing!

Frank
Lucas dedicated slabber
Woodmizer LT40HD
John Deere 5310 W/ FEL
Semper Fi

Seaman

JC, that was a good read you posted a link to.
I cut with a SUPER-SKIP chain, 11 links between each pair of cutters, and get a wonderful bandsaw finish. I am sure differences apply between Lucas slabbers and csm's.
Frank
Lucas dedicated slabber
Woodmizer LT40HD
John Deere 5310 W/ FEL
Semper Fi

jclvsall

Seaman, that website is a good basic lesson in milling sawchain theory.  I did resist the 0* filing until I tried it.  Then I switched all my chains over. 

I can't stress enough how important it is to get your teeth the same height as well.  

I see you are in Old Fort.  Is that the Old Fort on I40 near Black Mt?  I see the sign every week on the way to my mill in TN. I live in NC but mill in TN. 

Brian
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well armed lamb contesting the vote.  Ben Franklin

Brucer

Before I sold my CSM stuff, I had settled on:
full comp chain
0° top angle (90° to the bar)
0° side angle (file level)
45° tooth angle (as opposed to the usual 85° tooth angle.
Counterweight on the outboard end of the mill, to offset the weight of the head.
Kerf wedges behind the saw to keep the top board from pinching down on the back of the chain.

I still have a piece of birch in my basement, cut with that mill. It's 8" wide, 0.020" thick, and was originally 12' long before I started using it for veneer. The finish is smoother than a bandmill will cut. One little trick -- I cut the piece of the bottom of the cant ;D.

Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

ethanbrush

Quote from: jclvsall on April 12, 2014, 12:34:17 AM
Great question!  I have spent quite a bit of time in the jungles of the south pacific milling some huge and hard as a rock stuff with a chainsaw so I can relate to your issue. 

Several questions.

#1 How are you filing your rakers?  If you are not using a guide and flat file you should be.  They all need to be exactly the same.  The "bitey" symptom could very well be that the rakers are different.  You say the rakers are at .025ish  I usually took mine to .035 with good results.

#2 Are you biased with your decision to file at 10*?  I ask this because I was.  I was very skeptical to take the advice on this website http://www.sawmillchainsaws.com/sawchains.htm to file them back to 0*.  You read that right! 0*!  I decided to try it out one day in the jungle and was amazed how well it worked.   

#3 Are all your teeth the same size?  This question relates to the length of the cutting tooth.  If some are filed more aggressively than others and are shorter they will actually be different heights.  It will get real bitey if you have some tall and some short teeth.  It seems a waste but you really need to take every tooth down to the size of the smallest one on the chain!

#4 does your saw bar lay horizontal or does it stand up vertical when you are cutting?  I had some oiler problems when we were cutting big logs with the bar vertical.  The bar and chain were heating and dulling quickly. 


GREAT looking crotch planks by the way!

Brian

Brian, thanks for the advise.  Regarding your questions:  Overall everything should be quite accurate.  I check the rakers with a straightedge and feeler gauge and periodoically check the cutter length uniformity with dial calipers.  The rakers started out at about .032 and after a bunch of sharpenings are down to .025 now and I havent lowered them yet.  Maybe I will try the 0 degree grind, I am doing 10 just because that it what the factory spec is, but as you and  others have said, 0 may be preferable.  I think my lube is ok.  I dont have an aux oiler, but the saw does in addition to the auto and I pump it a lot when I cut. 

QuoteI cut with a SUPER-SKIP chain, 11 links between each pair of cutters, and get a wonderful bandsaw finish. I am sure differences apply between Lucas slabbers and csm's.
Frank

Interesting that less cutters would give a smoother cut.   I feel like I am not getting a smooth finish at all. 

QuoteBefore I sold my CSM stuff, I had settled on:
full comp chain
0° top angle (90° to the bar)
0° side angle (file level)
45° tooth angle (as opposed to the usual 85° tooth angle.

Wow, 45 degree.  That held an edge for a reasonable time?  I was thinking mine is too low and thats why its only getting one slab per sharp.  I did a 30 inch wide, 7' long spruce today on a fresh sharpen and it cut fast thru half of it then slowed down.  That just seems quick especially for soft wood.  Thanks everyone again for all the comments.
Timber Harvester 30HTD25
Stihl 075 w/ Sperber 36" CSM
Husky 550XP
Uniforest 45M
New Holland TC-45

ethanbrush

Timber Harvester 30HTD25
Stihl 075 w/ Sperber 36" CSM
Husky 550XP
Uniforest 45M
New Holland TC-45

Brucer

The 45° hook angle was a suggestion by Will Malloff in his book, Chainsaw Lumber Making. I also set my depth gauges to 0.035" -- the chain still cut smoothly.

I did make a point to keep my logs clean. Some species such as WRC are hard on teeth so I suspect I was doing a little more sharpening than if I'd stuck to the more conventional angle.

So you gotta decide -- do you want to spend extra time pushing the saw through a log, or sharpening chain  ??? :D .
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

Chop Shop

Ive cut tons of WRC with my chains at 20-25 degrees.   I can cut about a dozen ten foot long slabs with out sharpening.  I cut some fir and hemlock too.  Same results just a little slower is all.   I can cut a 10-12 foot long 24-30 inch wide cedar slab in under 5 minutes.    I use a ladder for my start/guide slab.

I run 3 foot alaskan mill on a 066 magnum.

I can get cuts as smooth as a bandmill.  Nice easy smooth push, never rocking back and forth making zigzag cut marks.



  

  

  

  

  

  

 

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