slow going milling

[Rosss]

I was milling today and roughly timed out how long it took me to mill a seven foot length of spruce 21 inches wide.
It took around 20 minutes and seemed very slow.

It was the second cut after cutting 14 feet of the same log. I had sharpened the chain prior to beginning the day using a file and a grandberg guide and set the raker depth at .030.

It is a Laser brand grandberg stye ripping chain where there are two kinds of teeth wide ones and skinny ones. I have never been able to get the actual specs to sharpen it from laser so went with 0 degrees for the wide teeth and 30 degrees for the skinny teeth. The chain may have been set at 35 on the skinny teeth at manufacture. It is my understanding that raker depth is set at different levels for different teeth on this kind of chain and I ignored this and set them for all for .030
I am still figuring out/experimenting with how to sharpen this chain and what settings work.

Apart from any sharpening issues, the saw seems to cut much faster when not in the chainsaw mill. I am wondering if something is off alignment wise with the mill. There was more vibration that usual today and the surface was less even than previous.

I have never timed it before but it has seemed to be slower lately, but I don't have background with similar logs to compare with.

I am milling with a Jonsered 2095 and it power doesn't seem to be an issue.

Does anyone have the sharpening specs for grandberg ripping chain?

What is a reasonable amount of time per foot of log?

Thoughts? Advice?

 

[BobL]

The more you mill the s- l- o- w- e- r it seems to get.

20 minutes for a 21", 7ft long softwood log sounds too long

I reckon dedicated ripping chain is of limited benefit in small wood.
Specialised ripping/skip chain is maybe only needed in much wider logs on much bigger saws to help take the strain off the power head.
After trying a few different skip patterns on bars up to 60" I still reckon its better to use full comp chain and adjust the rakers to suit the width being cut
On small wood, full comp chain with more teeth in the cut is the way to go.

Your extra vibe could be due to the lowered rakers.

I have never been able to get the actual specs to sharpen it from laser so went with 0 degrees for the wide teeth and 30 degrees for the skinny teeth. The chain may have been set at 35 on the skinny teeth at manufacture. It is my understanding that raker depth is set at different levels for different teeth on this kind of chain and I ignored this and set them for all for .030

I have never used Granberg chain but this is what it says on their website:

Most of the time, 3/8 and .404 chain will be sharpened at 10 degrees for both scoring and clearing. Occasionally however, the usual stock of 3/8 chain will be unavailable and we will have to use a different modification process. This 3/8 chain will be sharpened at 20 degrees for the scoring and 0 degrees for the clearing cutters.

I'd suggest do them all at 10º.
You might want to book marks their FAQ
https://granberg.com/frequently-asked-questions/

 

[Marine5068]

The more you mill the s- l- o- w- e- r it seems to get.

20 minutes for a 21", 7ft long softwood log sounds too long

I reckon dedicated ripping chain is of limited benefit in small wood.
Specialised ripping/skip chain is maybe only needed in much wider logs on much bigger saws to help take the strain off the power head.
After trying a few different skip patterns on bars up to 60" I still reckon its better to use full comp chain and adjust the rakers to suit the width being cut
On small wood, full comp chain with more teeth in the cut is the way to go.

Your extra vibe could be due to the lowered rakers.

I follow most of what you're saying Bob, but how do you mean 'adjust' the rakers?
What do you do for a narrower log as opposed to wider one, with regard to the rakers?

 

[BobL]

I follow most of what you're saying Bob, but how do you mean 'adjust' the rakers?
What do you do for a narrower log as opposed to wider one, with regard to the rakers?

Most members will know I am nuts about rakers and are probably sick of me hearing about this - so with apologies to those that have heard all this before.

Optimising the cutting speed in narrow cuts can can be done using greater raker depths and VV.
However, if you use the same chain with the lower rakers on wider cuts you may end up bogging the saw/chain down.
Using the same shallower raker depth chain used on wide cuts for narrow cuts won't cut as fast as it could.
In practice most folks select a raker depth that accommodates the widest cuts they will encounter and wear the less than optimum cutting speeds in the narrow cuts.
The alternatives are to change the drive sprockets and/or chain loops with rakers to suit the width because adjusting the rakers on the same chain to suit the cut width is a PITA and wastes cutter and raker metal.
Remember, its easy to drop rakers but to raise the rakers requires metal to be removed from the cutters, even of they are already sharp ie a wasteful process.

To bring on a "How much to lower the rakers" discussion requires knowledge of progressive raker depths. If you are not aware of this I suggest first reading the Sticky in this forum, or for an extra nerdy and detailed treatment of this look up this thread in the "Hot saws/chain sharpening" forum https://www.arboristsite.com/commun...ly-progressive-depth-raker-generators.114624/

RE: the OP's raker depths
How worn is your ripping chain? Even 0.030" deep rakers may not be deep enough is the gullets are too wide.
Maybe post a side on close up photo of your cutters and I will check them out for you.

As a general guide, stock new chains have raker depths that are 1/10th of the gullet width.
New 3/8 chains typically have a 0.25" gullet and a raker depth of 0.025"
If the gullet is 0.4" wide then the rakers need to be 0.040"
If the gullet is 0.5" then the rakers should be 0.05"
BTW The 1/10 of gullet width figure produces a raker angle of 5.7º - which I consider on the wussy side.
This angle has nothing to do with the top plate cutting angles. Chain manufacturers, probably think this is too complicated for the average punter and besides high raker angles carries some risks as you will see below.

I use a raker angle of 6.5º on 3/8" on my 880 with 60" bar in hardwood.
I also use 7º on a 3/8 loop for running in narrower wood, which I hardly ever use.
For my 441 with is used in narrow hardwood I run Lopro @ 7.5º with a 25" bar.
One AS member used 9.5º to mill all the softwood for his barn using a 36" bar on a 660.
Maintaining the appropriate raker angles throughout the life of the chain means you can use than chain till the cutters start to fall off and maintain close to the new chain cutting speed.
There is no free lunch with all this, expect greater vibe and much more meticulous B&C maintenance to stay on song.

If you use this concept on a bucking saw you will be amazed at how quickly really old chains can still cut but there is a greater risk of kickback. However, kickback is a non-issue on a milling saws so I feel OK about promoting this.

 

[Brian72]

I'm on the opposite end of the spectrum from Bob. He's very precise and I'm a bit lazy. Lol. (No disrespect intended Bob. I highly value your input and appreciate you sharing your knowledge.) I use Stihl RS chain and also have a few loops of Woodland Pro ripping chain from Baileys. With good sharpening and raker maintenance, any chain will do a good job. The ripping chain does leave a slightly better finish. Getting one end up and milling downhill makes a big difference. Let the weight of the mill do the work. Dropping the rakers will cut more aggressive. I did get a Granberg ripping chain but never used it. Don't want the hassle of sharpening two different angles and it's also more expensive.

Sent from my Moto E (4) using Tapatalk

 

[BobL]

I'm on the opposite end of the spectrum from Bob. He's very precise and I'm a bit lazy.

I'm sort of precise because I am lazy. As an unfit, overweight 60+ year old, when it comes to the crunch I don't have the grunt I once had to use to solve problems by brute force so try to physically find easy ways of doing things. I'm retired so time does not matter much and get my kicks of making gizmos, testing and experimentation. Making things easier often speeds up processes, leads to less wear and tear, and makes me smile.

In practice I'm way more casual than what I write. I rarely measure cutter lengths, if one cutter looks a bit longer than the others I give the cutter a few extra swipes. Cutters are filed by hand with a file guide so cutter top plate angles are approximate. Hook angles are set by choice of file and guide sizes. Raker angles are set with a digital angle finder but only to ~ +/- 0.5º in the quiet of my shop. When I'm in the field I don't usually bring out any measuring instruments and there's a fair bit f winging it. A few file swipes here, a few file swipes there seems to keep things humming along. I touch up the cutters to remove glint after every tankful of mix and swipe the rakers twice after every 3-4 tanks. If cutting is still not fast enough I swipe rakers twice again after the next tankful. I work slowly mainly because I get tired quickly and I'm in no rush. If I was doing this for a living I'd go broke real quick.

 

[Brian72]

I don't think any of us do this for financial reasons Bob. Lol. We all just love doing it. I certainly mean no disrespect towards anybody. I just find we all tend to over-think things. Milling is very much a hands-on learning process but these forums offer great beginner advice too. The feel of the saw will tell you alot about what works. Good sharpening is certainly the key.

Sent from my Moto E (4) using Tapatalk

 

[RajElectric]

My 066 with a 29" wide cut in sugar maple would take 15-20 minutes (hand winch pulling the mill, with the same chain you have) depending on grain.

Is your saw spitting out lots of dust?

 

[Rosss]

My 066 with a 29" wide cut in sugar maple would take 15-20 minutes (hand winch pulling the mill, with the same chain you have) depending on grain.

Is your saw spitting out lots of dust?

Yes to dust.
Prior to "sharpening" and setting the rakers at .030 had less dust and more 1" -1.5" pieces that looked liked grated cheese.
Some of the rakers had quite a bit of material taken of them.
I would have guessed they were at .020 or less.

 

[Rosss]

diagram of ripping chain with different raker heights for scoring and clearing teeth.
I am sure I saw a diagram where the first clearing tooth had a higher raker than the second clearing tooth coming behind it.

https://www.loghomestore.com/wp-content/uploads/2017/03/ca0010-ripping.gif

 

[RajElectric]

Lots and lots of dust?

I've only been milling a very short time, I kind of gauge the sharpness of the chain by the amount of dust coming out. There is certain size "cone" of dust I see coming out of the saw when the chain is good, and what the pile looks like. Small small chips, more dust like. If I cut into a branch union or some other grain it'll come out a bit stringy, but still a fair amount. I've hit a hidden pocket of dirt, or small nail, and I can see there is a noticeable drop in dust coming out, and more resistance to cutting and the saw RPMs not dropping.

 

[BobL]

Excess dust means the chain is not set up correctly with either too steep a top plate cutting angle and or rakers set too high (raker angle too low).
Feel free to post "side on" close up pictures of your cutters for a diagnosis.
Like this if you can - or at least as close as you can (no need to worry about a ruler)

 

[ChoppyChoppy]

I didn't realize chainsaw mills are THAT slow. Wow.

I thought ~2 mins a board on the Woodmizer was slow!

I like watching big mill videos that the log is bzzzz, bzzzz, bzzzz and boom done.

 

[JTM]

To me the cutter/ raker angle is no different than a planer. Its optimum is determined by the power of the saw, the hardness of the wood, and the number of cutters in contact (width of the cut) with the wood. Keep a systematic approach and you will learn pretty quick what works best for the setup. I have never used milling/ripping chain but get a decent finish using technique, not seesawing in the cut and easing back in the cut after setting wedges. I practice these things BobL discusses and has made my milling experience rather enjoyable. Good luck.

 

[BobL]

To me the cutter/ raker angle is no different than a planer. .

A chain only acts like a plane when noodling otherwise it is somewhat different from a planer.
In a planer there is no raker (although in some ways the sole of a plan can be considered a sort of raker) and the blade is held at a fixed angle to the wood.
In cross grain cutting chain, cutters cutting rock their way into the wood and tear rather than shave out chips.

It starts by the top plate cutter edge taking a bite which forces the cutter backward and lifts the cutter link off the bar slightly (increasing the chain tension) the until the raker makes contact with the wood, the cutter edge bite in further rocking it back until teh raker starts trying to dent the wood, This continues until the combined vector sum of the engines force and the chain tension tears out the chip. Its actually a quite savage process (this is also why chain saw injuries are very nasty - flesh is torn more than cut out!)

Its not necessary to understand all this provided you understand that rakers play an important role in the cutting process and for optimum cutting should have as much attention paid to them as the cutters

 

[Rosss]

I spent some time sharpening the chain and then took it off to make sure the oiling hole is clear as it clogs, more so when it is cold out.
After setting the tension in the chain the, chain would actually kind of get stuck in the slot it runs in and would be grabby, catchy when pulling it up to check tension.
It also didn't run well in by hand on the bar. It was difficult to put on and just seemed out of kilter. I wondered if I had got a .063 guage instead of .058 but is says 58 on the drive part of the chain.
Anyways I put a new bar I had bought to modify to fit on a poulan 850 and got a chain that I had stopped using till I learned how to sharpen these milling chains and put it on and major difference. It slides easier on the bar, it is easier to install and get right in the rim drive, the chain will move both forwards and backwards, quite a major difference.
I sharpened it, but left the rakers for now. I am pretty sure they need to get lowered as it has been sharpened a number of times but they have never been adjusted.
I don't know what is up with the other chain, it didn';t seem to fit well on the new bar. The older bar is not old at all. the rails seem in good shape but there are little nicks out of the metal just before and after the nose sprocket, in the actual metal of the nose sprocket where the rails are in it.
Not sure what caused that. I have mostly milled with the bar but did use it to cut off one stump.

I will post a picture of the current chain so you can provide some input Bob, and thank you I appreciate the time and effort you take to provide input and assistance!

 

[BobL]

I spent some time sharpening the chain and then took it off to make sure the oiling hole is clear as it clogs, more so when it is cold out.
After setting the tension in the chain the, chain would actually kind of get stuck in the slot it runs in and would be grabby, catchy when pulling it up to check tension.
It also didn't run well in by hand on the bar. It was difficult to put on and just seemed out of kilter. I wondered if I had got a .063 guage instead of .058 but is says 58 on the drive part of the chain.

Even a really worn 058 chain should not really be able to fit into a really worn 063 bar.
It could be the bar rails are slightly mushroomed? - have you got a micrometer caliper to measure the groove with? It does not take much mushrooming to restrict chain movement.
If so, the mushrooming should be removed from the outside and inside of the rails by dressing the bar. As many of the nicks on the bar rails as possible should be ground away or they will propagate and break off enough of the rails to render the bar useless.

I made myself a proper bar dressing tool but the easiest way I found was putting a thickish cutting wheel in a small table saw (make sure there's no sawdust around) and lay the bar on the table saw table and make very light passes against the side of the cutting wheel and move the bar along is natural arc. You must keep the bar moving at all times or the wheel will grind a flat spot on the bar.

 

[Rosss]

How would I check to make sure the chainsaw bar is at 90 degrees to the mill rails?
I am concerned that the clamps that hold the bar are not aligned with each other and leaving the bar a little out of kilter.

 

[M.R.]

Easy enough, tougher to put into words/print.

A couple straight edges... 2’, 3’, or 4’ rulers
Like an H on its side ... w/the chain removed
from the bar measure (a few points along the length of the bar) the ends of the ruler (centered on bar) other on rails.
In tune / parrel will be equal distance on the
Ends of rulers/straight edges, shimm
adjust till they are.

A couple small clamps with a short piece of angle iron
Or even a piece of wood to clamp & hold the straight
Edge true on the bar will take less hands and frustration.

 

[BobL]

I would use a digital angle finder(DAF) - place the DAF on the bar in the right orientation and zero the DAF. Move to the DAF to the mill upright and check the new DAF reading.
The bar also needs to be parallel (not twisted) and placing the DAF at each end of the bar can check that
The bar also needs to be parallel to the mill rails in the direction perpendicular to the bar, if not the chain will be constantly under a sideways force in the groove and this can lead to long term problems.
Small angle difference can be corrected using washers or shims.

DAFs are useful for several aspects of milling and I keep one in my milling tool kit.
The main thing I use it for is to check the raker angles.
I also use my DAF to quickly check for twist in any piece of milled timber (Yes I know how to use winding sticks too)
The other regular use is to check the log rails are not twisted.
I used to carry a piece of ally to lay across the rails so that I had a place for the DAF as shown in the pic below but I now just use the tops of the log rail angle iron clamps as shown.
If the rails are twisted I lift one of the ends of one of the Unistruts with thin wedges

A DAF is really useful for setting and checking stuff on a BSM is parallel