Pine, pitch, set, lube ... my experience

[John Bartley]

Hi all,

First of all, I am a newbie at milling, but I'm learning fast ... so here's what happened to me;

Late December ... bought a new mill ... sawed about 200bdft of frozen Elm ... all went well ... using WW with water and Pine-Sol with the stock cheapy blade that came with the mill ... sharpened the blade ... 10', .023"set

Late January ... started sawing some green, frozen White Pine ... logs about 28" x 9' ... all went well ... sawed about 200bdft ... took the blade off to check ... not bad ... might as well sharpen and set anyway (good practice eh?)

Mid February ... installed a brand new blade ... another nice green, frozen White Pine log .... about 28" x 9' ... same lube, same tension etc .... had waves you could surf on ... fast feed - slow feed - no change ... checked everything ... couldn't see anything wrong or different other than a lot of pitch buildup ... hadn't sharpened the old blade yet, so couldn't try it ... tried another new blade - same .... major depression ... had to have a hot chocolate.

Thought about it for a while ... chatted with a friend ... had another hot chocolate ... decided that the set was too thin ... took the first new blade ... checked set - was .019-.020  but still seemed sharp ... cleaned and reset at .024 ... sharpened at 10' ... reinstalled and test ran ... better, but very slow feed and any knot causes a major detour ... noticed a lot of pitch buildup again ... tried more lube - less pitch, but still some waves .

Finally ... the blade box recommended 1250psi tension, but I cranked it up a couple of hundred psi at a time until I reached 1750psi, and while it was much better, I was still getting pitch buildup ... opened the lube until the pitch went away ... so did the waves

Summary : the solution in this case was; more set - more tension - lots more lube.

When everything is working properly, we can cut about 200bdft of green frozen pitchy pine in a bit less than an hour.

I realise that I've sort of narrated here without asking any questions. I don't have any questions ... I just thought I'd lay out my experience in case anyone else can profit from reading it.

cheers eh?

[Dan_Shade]

what type of saw do you have?  how are you reading tension?

psi can be confusing when you relate it to force,  1250psi with a 1" diameter cylinder creates a different stretching force than 1250 psi with a 1 1/2" diameter cylinder (provided you are checking hydraulic pressure).

if the psi is the strain on the band, then 1250 psi sounds really low...  on my LT40, I crank up the tension to about 2700 or so on the guage.  I should do the stretch test with that and see what it comes out to.

check out this thread:  http://www.forestryforum.com/board/index.php/topic,10765.0.html

[John Bartley]

Dan,

Great reply - very informative - thank you!!  Now I have to do a bit of research on my mill and see exactly what I have.

what type of saw do you have?  how are you reading tension?

I have a Champion Mill made by Gilbert in Quebec, 25hp, 20" bandwheels, using 1.25", 0.042", 7/8" silicone steel bands with hardened teeth and back. (Note: the original cheapy band sold with the mill is described as a spring steel band - maybe uses less tension? - I'll find out...)  The band tension is set using a gauge on the cylinder as shown here :



Because I don't know the diameter of the hydraulic piston, I can't calculate the force. Because I don't know the required blade tension, I can't do the calculations for stretch .... so ... all in all, I would say that a telephone call to Champion is in order.

I'll do the research on this and post my findings here once I have the answers.

thanks again!!

John

[woodmills1]

Pine can be very frustrating I use woodmizer .045 with 30 thousanths of set.

[slider]

Try using tide ultra liquid in the orange jug ,3 cap fulls + 1 cap of pinesoll in 4 gal of water this works well for me .Almost as good as diesel but not as messy.  slider

[ARKANSAWYER]

  I have found that if you cut lots of pine a 13 degree blade with about 0.028 set is good.  For general cutting I find a 10 degree blade with about 0.021 set will get you by most of the time.  I use WM blades with 10 degree on both mills.  How thick your blades are make a differance as well.  On the LT40 we use 0.045 blades and on the LT70 0.055 blades.  I have used 0.055's on the LT40 and they do cut better but do not last as long.
  John I have to admitt you were quick to look for the cause of your sawing problem and a way to solve it.  Welcome and keep sawing with your eyes open and learning all you can, makes it more fun.

[John Bartley]

Hey guys,

Thanks for all the posts, the variety of thoughts and opinions and especially for the tech info on band tension. I made a few telephone calls last week to the two saw band manufacturers whose bands I have, and I learned a LOT!!  We've had some poor weather here and other things to do, so things were sort of "on hold", but we had a loader in today and he piled up a half dozen nice big white pine logs for us, so we're itching to get back at it. Based on what my blade manufacturers told me, I've sharpened and set a couple of fresh bands, and once I've done a few hours with them I'll be back to report what I've learned and  how my experimentation is going.

cheers and thanks all

John

[slider]

John,I don't know what lube system you are using but if you are having pitch build up don't forget the bottom of the blade.My first mill had a drip system that didn't lube the bottom of the blade well in heavy pitch.A shot of wd-40 underneath helps. Good luck   slider

[MartyParsons]

John, What about drive belt tension? On the Wood-Mizer we check it 1st 5 hours then every 50 hours. Better check with the manufacture of the mill and get the correct spec, for drive belt tension. Blade tension on the Wood-Mizer Double hard we like them tight compared to other blade manufactures. Our gauge reads 2500 to 2700 psi.
Both these issues will cause blades to dive. The belt being loose causes the blade to slow ( belt slip) as proper blade tension will let the blade gain beam strength.
Marty

[John Bartley]

Slider,

Thanks for the reminder. My mill (an inexpensive one) only has a drip lubrication, so only the inside of the band gets lubed. So far it hasn't been a problem as the only pitch buildup has been on the inside and there has been absolutely none on the outside (bottom) - not sure why that is.... but I will carry a can pf WD40 with me tomorrow - can't hurt eh?

Marty,

I checked the drive belt tension at the last band change - seemed fine, but you make a good point - I'll keep an eye on it. Band tension is a point that I'm still working on. The hydraulic band tension cylinder on my mill is 1-1/2" diameter, and when I take the  20,000lbs/in² of strain that Hakansson (they make MillMaster & TimberWolf bands) says is correct for my bands and do the math, I get approx .0035" for a 5" measurement of stretch on the band. I did that measurement a few times to test it and I come up with about 1300psi at the cylinder. The sawmill manufacturer says to use 1250psi, so it's pretty close. But ... it cuts better at 1500-1700psi (almost 30,000psi strain). I did find that the box of bands I had as spares were #86 bands, so I've pushed the set out to .025" and sharpened them at 10'. Hakansson also says that I should sharpen the bands fresh out of the box before using them. I wonder about that as they feel pretty sharp before I touch them. I'm hoping we'll see tomorrow - if it doesn't snow ... again .... dad-blasted snow!!!

BTW - I erred in an earlier post when I said that the band on the mill when new was a cheapy band - my mistake in saying that  ... it turns out that it is a Munksfor band - about the best band that the mill manufacturer sells - no wonder it cut so well - .024" set and 10' angle and sharp right out of the box.

cheers eh?

[logwalker]

Welcome John. Are you running roller guides? If so that would explain the buildup only on the top of the blade. The rollers roll the pitch laden sawdust onto the blade. No roller on bottom and no buildup usually.

[John Bartley]

Welcome John. Are you running roller guides? If so that would explain the buildup only on the top of the blade. The rollers roll the pitch laden sawdust onto the blade. No roller on bottom and no buildup usually.

Logwalker,

Yes, I am running roller guides, and they're the style where the roller is on top only and is flanged to act as a thrust bearing also. The band stays clean if I use a lot of lube and fortunately warm weather is coming so I'll be able to pour the water/soap to it and keep it clean. I've been using a WW fluid/water/pine-sol blend, and I'm sure there's better, more efficient and planet friendly solutions to blade lubrication. As I gain experience and learn some more about these things I'll change my ways, hopefully for the better both financially and environmentally.

cheers

[logwalker]

John, there is a wonderful, naturally occurring bacteria in soil that loves to digest the small amounts of diesel and bar oil that I feed them. If I was to stop I think they would get upset. Sure don't want to upset Mother Nature. 

[Skip]

If you can find a product called Ballistol try it  cut with water no sap ,pitch, rust, all I use. Amishman who sharpens my blades always comments on how clean they are

[John Bartley]

Skip and LogWalker,

Thanks for the suggestions guys!

Here's a bit of an update ... these are mistakes that only a newbie like me could make I think. I checked my grinder setup and as it came to me from the factory it was set at 12^o so I adjusted to to 10^o. I also checked the set on a "new from the box" band, and they're at about 0.021"-0.022". The original band on the mill (which cut well) was set at about 0.024". I took three new bands, set them at about 0.025" and then sharpened them (yes, the new ones) at 10^o. Yesterday and today we sawed about 600-700 bdft (estimates only - didn't measure). I used two bands and didn't have a single wavy cut. I cut five logs, averaging about 24"diameter and 12' long and spent about three hours of motor time (Tiny Tach on the motor).  I'm using just enough lube to keep the bands clean of sap, and in two days we used 16 litres of 50/50 WW & water mix with a bit of soap also mixed in. I'm also using much less tension on the band. I'm down to the 20,000psi that Hakansson recommends, there is much less effort required by me to push the band thru' the log, and I can hear the band "singing" in the wood.

So, tooth set and grind angle, as well as an appropriate amount of lube was the final solution to my wavy cuts in fresh White Pine.

Finally, pushing the set out to 0.025" has NOT left any tooth marks at all, something thaty I was a bit worried about.

Sorry to be so long winded, but maybe someone else will benefit from my experience.

cheers all !!

[Dan_Shade]

I think you'll find that as long as your set is pretty consistant, you won't get marks.   one tooth that's pushed out will leave marks.