Washboard surface when milling

[glennschumann]

I've got several bars for my Alaskan set up with an 066, but I consistently get a very rough "Washboard" surface with when I use my 24" bar. It is very used, but I have closed and ground the rails, and I still get a wavy surface (It is an Oregon 3/8" 0.063 sprocket tip. I've used one chain ground to 10* and a new one ground to 30* with the same results. The only time it clears up is then the chain is dulling, and I have to put pressure on the mill to get it to cut. Then, sometimes, I get a reasonable smooth surface. I have one 36" Stihl bar that really could use rail closing, but it gives a smooth cut. My 42" bar is new (Oregon powermatch) and leaves a smooth cut. Before I go get a new bar, does anybody have any thoughts?

FYI the tip is securely fastened, and turns easily. The rails are also well aligned with the bar rails. It isn't so warn that the bottom of the drive links are hitting the bottom of the track.

Any thoughts?

Many thanks in advance to the wisdom of AS.

 

[timberwolf]

Maybe a light stoning on the chain. (rubbing a large gritstone on the outside edges of the cutters). Takes the side attack off the teeth so the pull into the wood less on the sides. Maybe try a chain filed closer to 0 to 5 deg.

 

[BobL]

I've got several bars for my Alaskan set up with an 066, but I consistently get a very rough "Washboard" surface with when I use my 24" bar. It is very used, but I have closed and ground the rails.

It sounds like that bar is well beyond its use by date. Even if you close the rails you cannot close in very inside of the rails close to the groove. This still allows the chains to wobble.

A is the normal groove. B is a well worn (ie throw away) groove. C is B with the close up groove, chain (especially used chain) can still wobble.

The used chain with the 10º angle will behave the same as a new with 30º chain.
Running new chain in that bar will not be good for it. It's hard to do, but toss that bar and get a new bar and sprocket to go with your new chain.

BTW we have less of a washboard problem with our hardwoods here is Australia. No amount of grunt can slice thru the timber fast enough to creat washboards of many of our trees.

 

[BlueRider]

twisted/bent bar

I have the same problem with the 32" bar on my 038M. I am pretty sure my problem is a bent bar. My bar has a slight twist in it. It looks ok on the saw but when I take it off and lay in on a flat surface you can see a 1/4" twist.

 

[johnb]

change your grind

use a 15 degree/ 25 degree hand grind on your chain. file against the chrome edge on the cutter opposite of what is normally recommended. This will sharpen the chrome and give your chain a slight pulling effect to draw in the saw. Don't over do the rakers!! happy milling The Hoosier

 

[motoroilmccall]

One other thing nobody has mentioned thus far... Make sure you're using semi-chisel chain. Chisel has a tendency to pull to the side a lot more than semi-chisel does.

 

[slabmaster]

I think BobL is right! Time to toss the bar.THey only are good so long for milling anyway.Save that bar for crosscutting.THat 1/4" twist is what's causing the washboard as it's rocking back and forth as you cut. Mark

 

[2506]

Not the Bar ?

I have a brand new set up. New 066 with a new 42" Oregon Powermatch bar, new 375/.063 ripping chain from Baileys. I get the washboard effect as well. The bar has a slight "S" curve in it due to being dropped by FedEx in shipping although I am not sure if it is enough to cause this. When milling with my Rancher 455 and a 24" bar, 375/.050 ripping chain, it results in a smooth finish. The only difference except for the slight curve in the 42"er is that the 24" bar was covered up in the log, where as the 42"er was mostly exposed due to milling only an 18" oak log (rocking?). I am going to try a shorter bar on the 066 and see if it makes a difference.

 

[slabmaster]

.063 is not good for milling..050 is the best i have found through experience.If your bar has an s bend in it, that would cause the washboarding.I don't think dropping a bar could bend it. Mabey the fedex man ran it over with the delivery truck.It was probably bad when sent.I've had no problem milling with .050 and strait bar in any size length.

 

[BobL]

To a certain extent washboard depend on how fast the milling happens. In very hard wood I can still get a smooth finish with 404 30º top plate chain, while in very soft wood I can get washboard with 3/8 if I put too much top plate angle on the cutters.

One can think of the chain as making a series of circular gouges like this.

On the left hand side the wood is green - cutting is quicker so the chain makes a deeper cut with each pass, by the time the next tooth passes that lengthwise line along the log there is a little ridge left behind.

On the right hand side the wood is hard and so a tooth only nibbles with each pass but removing more of the timber normally left on the ridge. The top and bottom rows are the same except I have removed the black lines around the circles.

Same thing happens in large circular saws that cut wood too quickly.

The outcome of all of this is, provided your bar and chain are all ok, if you want a smoother cut just cut slower or get a higher revving saw !!

 

[deeker]

Keep posting guys.... I am learning....

 

[BlueRider]

.063 is not good for milling..050 is the best i have found through experience.If your bar has an s bend in it, that would cause the washboarding.I don't think dropping a bar could bend it. Mabey the fedex man ran it over with the delivery truck.It was probably bad when sent.I've had no problem milling with .050 and strait bar in any size length.

Please explaing. I don't see how the guage of the chain would have any effect on milling.

 

[glennschumann]

Thanks for the thoughts... I haven't checked to see if the bar has any sort of slight twist or bend. I've ruled out the major bends, but I'll look more closely tomorrow.

The chain really didn't wobble after I closed the rails, but again, I'll look more closely tomorrow.

I have used both 0.050 and 0.063 with good success. It was a couple of years ago, and it is hard to remember, but I thought I had good luck with this bar when I first used it. Of course that is when I didn't know squat about milling, you know, I didn't know the difference between an 026 and an 066. Hee Hee, now I have a pair of 066's and a 3120.

On a side note, I was at a lumber yard the other day.. quite a display of bookmatched crotch walnut, 24" oak and a few others including a 48" wide slab of willow. That slab was nice, but us$750? zowie! I'm in the wrong business.

 

[slabmaster]

Please explaing. I don't see how the guage of the chain would have any effect on milling.

I found that .063 took power from the saw and cut slower than .050.I mainly cut hardwood . It might work better in softwood.My 394 husky labored alot more using the .063 set up milling hardwood.So i found that .050 works the best because it is easier on the saw and is faster cutting.

 

[BobL]

.063 is not good for milling..050 is the best i have found through experience.

It's not the 063 bar groove that slows you down but the chain that rides in the groove. Some 050/063 chains have the same ties and cutters and only the drive link thickness is different eg stihl RSC and RSC and you won't see and difference in milling with these chains. 050 does have a nice range of low profile chains available, these have a smaller kerf and thats what makes the difference.

It also depends what you are milling. I found I can use the low profile 050 chains up to 24" in aussie hardwood ( many of our hardwoods are harder green than your Osage Orange is dry!) above that length they stretch too much and so I stick to 3/8" - 063. I expect you can go to much longer lengths in north american timbers.

 

[BobL]

Here are some pics of some more lemon scented gum I milled today. Sections of this log were over 40" wide (9 ft long) but I decided to stay with the 42" bar (39.5" cut) so I trimmed off the sides. Did I say how hard this timber is - using a brand new chain it took two full tanks of fuel to cut this slab.

Here is the washboard difference between 30º chain (Bottom RH side) and 10º chain (Top LHS)

 

[BlueRider]

nice looking slab. It looks a lot like chinese elm, and as hard as chinese elm is I suspect that slab of yours is a bit harder. If you were a few 1000 miles closer I would try to work out a swap for some of that stuf.

 

[glennschumann]

Bob, that wood is beautiful... thanks for wetting it to show what it will look like finished. Thanks also for the thoughts about low profile chains. I'm considering using a Stihl low profile chain when I have to replace the 3/8 0.050 RSC loop for my 36" bar. Maybe that is too long? I'll keep thinking about it.

My washboarding is much more radical. Sorry, I don't have a picture right now... I dropped the girlfriends laptop and I had to go the library computers to order new parts to get it working again... when that is back up an running, I'll try to post a picture... if she ever lets me near her machine again...

 

[BobL]

nice looking slab. It looks a lot like chinese elm, and as hard as chinese elm is I suspect that slab of yours is a bit harder. If you were a few 1000 miles closer I would try to work out a swap for some of that stuf.

Just a bit harder . . . . . .Dry Janka hardness for Chinese Elm is 1690 lb, whereas for spotted or lemon scented gum its 2473.
For comparison, Hicory/Pecan is 1820, and Dogwood is 2150.

Even when green, spotted gum is as hard as hickory is when its dry (12%)!

The logs I'm milling logs are already partially dry, certainly the ends are, and they are like cutting stone! Its actually is worth docking 6" of the end of the log before starting to mill otherwise you immediately blunt the chain in that first inch. It's less important at the end of the long because I resharpen again anyway. I'd say right now inside the log would be like cutting Osage Orange.

Bob, that wood is beautiful... thanks for wetting it to show what it will look like finished. Thanks also for the thoughts about low profile chains. I'm considering using a Stihl low profile chain when I have to replace the 3/8 0.050 RSC loop for my 36" bar. Maybe that is too long? I'll keep thinking about it.

it depends what you are cutting and how cool you can keep the chain. If it's mainly softwoods and you have good oil delivery you can probably do it.

My washboarding is much more radical. Sorry, I don't have a picture right now... I dropped the girlfriends laptop and I had to go the library computers to order new parts to get it working again... when that is back up an running, I'll try to post a picture... if she ever lets me near her machine again...

The degree of washboarding depends on what you are cutting and the angle of the top plate. Soft wood and higher angles will usually give the most washboarding.

 

[glennschumann]

Forgive me for asking what seems like a silly question, but with the low profile chains (Stihl picco), does one need to change the rim sprocket and roller tip to acomodate the 0.365 pitch or can I still use a 3/8" tip and rim sprocket? I ask because I see they advertise it as 3/8" picco, but qualify it as 0.365. Are these close enough to overlap, or are they really to far apart... 4 drive links wrapped around rim sprocket does add up to 0.040 difference, and even though I design buildings several hundred feet long (with a bunch of other folks), that seems like a lot in this application.