Ripping chain grinding questions

[BobL]

Most people don't realise that rakers penetrate very slightly into the wood so the shape as well as the depths are important.

Few people realise that CS chain cutters don't act like mini-planes during cross and end grain cutting. During each pass the chain porpoises on the bar so only every 3rd or 4th cutters grabs substantial amounts of wood. These cutters and rakers actually "rock" their way into the wood - final amount of "wood grabbed" by a cutter is determined by cutter geometry and raker depth a profile. The softer the wood the more the rakers penetrate.

If the rakers have flat tops - or even shallow angled tops - they cannot penetrate as far, so cutters cannot penetrate as far either. If flat top rakers are used the rakers need to be dropped even further than usual.

Flat top rakers also usually means more of a corner at the end of the raker top. This adds unncessary friction/laod to the chain.


The raker above looks pretty good, the raker angle works out to about 7.5º which should make nice chips in software woods. Not sure about the cutter - looks like some bits are hanging off it. I would definitely clear out the gullet to assist with sawdust clearance.

 

[Mad Professor]

I'm in bennington County myself. Billy is enjoying retirement so far, I spoke with him a few weeks ago & he is doing well. I miss his shop as well.

Glad to hear our friend Billy is doing well! He was a better dealer, and mechanic than any of the larger "certified" dealers in the area. He knows all the old saws inside out. I used to spend a 1/2 hour talking with him most times I stopped to get parts.

I don't have the fancy Stihl seal puller, and Billy would install seals for $15 labor, sometimes same day, if you brought in a clean saw with flywheel/clutch off and cleaned up in there too.

Billy's closing caught me by surprise. I wanted to ask him about the piles of parts saws he had in the cellar workshop. I still have his cell # maybe I'll give him a call.

Good to hear from a fellow Vermonster too! Where is your favorite saw shop now that Billy has retired? I have lots of old Stihls, and some Homies and Huskys too. PM me so we don't derail this thread.

Take care. MP

 

[vtfireman85]

Most people don't realise that rakers penetrate very slightly into the wood so the shape as well as the depths are important.

Few people realise that CS chain cutters don't act like mini-planes during cross and end grain cutting. During each pass the chain porpoises on the bar so only every 3rd or 4th cutters grabs substantial amounts of wood. These cutters and rakers actually "rock" their way into the wood - final amount of "wood grabbed" by a cutter is determined by cutter geometry and raker depth a profile. The softer the wood the more the rakers penetrate.

If the rakers have flat tops - or even shallow angled tops - they cannot penetrate as far, so cutters cannot penetrate as far either. If flat top rakers are used the rakers need to be dropped even further than usual.

Flat top rakers also usually means more of a corner at the end of the raker top. This adds unncessary friction/laod to the chain.

View attachment 1014744
The raker above looks pretty good, the raker angle works out to about 7.5º which should make nice chips in software woods. Not sure about the cutter - looks like some bits are hanging off it. I would definitely clear out the gullet to assist with sawdust clearance.

How do you recommend filing or grinding them to be rounded? Or is it a multi step process take the tip down and then round the front? Particularly difficult I have found out recently is stihl chain. I bought a bunch of them from my local dealer for use in my Husqvarna saws. I find the rakers extremely difficult to file and have been venturing into doing them
On the grinder.

 

[link]

The chain stop on your grinder looks better than mine.

That's because it is DIY made on my CNC router.
I'd recommend one of the Jollys, you can get them more affordable than Oregon and they are pretty decent as I have heard/read. Better be a full size grinder - not the small plastic frame hobby stuff with fixed angles.

 

[link]

Not sure about the cutter - looks like some bits are hanging off it.

Thats a melt edge, I usually don't get them since I use my cloth with water with my left hand about every second. But if the wheel is saturated with steel residue and really needs dressing - and I need to grind away a lot like .020 (done in multiple takes at about 1 sec. on and 1 sec. off), this might happen. The paper thin metal flaw will brake off with the touch of your finger nail, definitely if you put it through wood at 25m/s. And for the record - thats not a rip chain.

 

[link]

I know you all hate this video that I made; takes too long, too much work, etc...
But this chain is twice the thickness of your regular chainsaw chain, and - it is a good place to start.

 

[BobL]

How do you recommend filing or grinding them to be rounded? Or is it a multi step process take the tip down and then round the front? Particularly difficult I have found out recently is stihl chain. I bought a bunch of them from my local dealer for use in my Husqvarna saws. I find the rakers extremely difficult to file and have been venturing into doing them On the grinder.

I usually use Pferd or Valorbe files for rakers. I keep these files protected in a plastic sleeve or short piece of hose so they don't get damaged. Tap the file regularly while filing the rakers to keep them clear.

This is how I do mine. Sorry the vid is not very sharp (ha) it was taken on an old phone 10 years ago but you should be able to just see the digital angle finder (DAF) screen to see I'm setting the raker angle to ~6.5º. The base of the DAF is placed on the top of a cutter and rotated to touch the raker.


Couple more comments
I don't set the raker angles with the digital angle finder as shown in that video very often. I usually do them when the chain is new *new rakers are always too high) and then when milling I touched up *2-3 swipes) the cutter after every tank of mix. The rakers get touched up (2-3 swipes) after every 3-4 tanks of mix. Then I might check a few raker angles when I get home and touch up if required.

I usea a raker angle of 6.5º for 42+" chains and 7.5º for <42" chains - this is for our Aussie hardwoods - higher angles can be used for your softer woods. There is a trade off, greater vibe and wear and bar an chain tear. Auxiliary oiling on a chainsaw mill helps minimise this. Also greater kickback potential when not used in a chainsaw mill.

 

[vtfireman85]

I usually use Pferd or Valorbe files for rakers. I keep these files protected in a plastic sleeve or short piece of hose so they don't get damaged. Tap the file regularly while filing the rakers to keep them clear.

This is how I do mine. Sorry the vid is not very sharp (ha) it was taken on an old phone 10 years ago but you should be able to just see the digital angle finder (DAF) screen to see I'm setting the raker angle to ~6.5º. The base of the DAF is placed on the top of a cutter and rotated to touch the raker.


Couple more comments
I don't set the raker angles with the digital angle finder as shown in that video very often. I usually do them when the chain is new *new rakers are always too high) and then when milling I touched up *2-3 swipes) the cutter after every tank of mix. The rakers get touched up (2-3 swipes) after every 3-4 tanks of mix. Then I might check a few raker angles when I get home and touch up if required.

I usea a raker angle of 6.5º for 42+" chains and 7.5º for <42" chains - this is for our Aussie hardwoods - higher angles can be used for your softer woods. There is a trade off, greater vibe and wear and bar an chain tear. Auxiliary oiling on a chainsaw mill helps minimise this. Also greater kickback potential when not used in a chainsaw mill.

Thank you for the input, I willlook for those. I also have access to Swix and SVST files , perhaps they would be high enough quality to cut. Inhave a similar angle finder and will give it a try to figure out what i am dealing with. You mention Australian hardwoods. I wonder how they compare to our oak, maple, ash and walnut. Considering i am usually using a double bar with 2 390xp saws would you suggest anything different for raker angle?

 

[BobL]

Thank you for the input, I willlook for those. I also have access to Swix and SVST files , perhaps they would be high enough quality to cut. Inhave a similar angle finder and will give it a try to figure out what i am dealing with. You mention Australian hardwoods. I wonder how they compare to our oak, maple, ash and walnut.

The softest timber I would mill is about as hard as the woods you mentioned. The average would be as hard or harder than hickory, while the hardest would be harder again. Some Aussie hardwoods from really dry parts of the country also contain a lot of silica which is a rapid chain blunter which is one reason why I run a slightly steeper top plate cutting angle (ie less hook) but for woods the manufacturers recommendations would be fine.

Considering i am usually using a double bar with 2 390xp saws would you suggest anything different for raker angle?

The best thing is to determine the optimum for yourself using the "old school raker setting method"

Take 3-4 swipes off the rakers - try milling, repeat until the chain starts to grab or vibe becomes unacceptable in the cut. If you go too far take a few swipes off the cutters.

Then measure the raker angle and that's the angle to use for that particular setup (wood, power, cut length, chain type, drive sprockets etc)

 

[Husky77]

It seems most are looking at the chain as a whole, in fact each cutter should be treated as a single unit. If you hit one cutter do you take everyone back to that length? Been there and learnt many years ago the hard way. If your doing it for a hobby fine just carry on as you are but if your doing it for a living you soon learn and cut faster for longer by looking at a cutter & rake as what they are, single cutters. Of course they all cut as a unit but each on their own if that makes sence. A grinder will give you good results of every one the same, but if your at it long enough you maybe left wondering why some people cut faster than others. Lifes a learning curve, every day we learn and when we stop learning its time to move on.

 

[056kid]

As the post above me outlines,I was always under three impression that chisel length variance does not matter so long as each chisel bit is in orientation with it's own individual raker. I know this is true with cross cutting as I've hit plenty of crap that trashes one side & not the other leaving me with no choice but to file off a good chunk of that entire side. After setting the rakers, no problems. The Carlton File O plate accomplishes this task as well as putting a forward rake on the raker. The softwood depth sounds appropriate from what I read here.