Now time for First sharpening

[oldsaw]

Andrew, look at it this way. There is no "perfect" cutter, only approximations to it. It's always a trade off between speed and durability. You are trying to strike a balance on geometry, while maintaining some semblance of order on cutter length and rakers. Kind of like "organized chaos." You do the best you can, and a real high end grinder can get you consistency on tooth size and raker height, but can't do anything with the natural compromises of cutting angles, except make the compromise consistent.

 

[BlueRider]

In my previous post about hook angles I forgot to mention a vary important effect hook angle can have on chain performance, quite possibly THE most important one to understand. Bob touched on the fact that a more acute hook angle will cause the chain to self feed. in the extreme it can cause the chain to be "grabby" excess power can cancel this out and this is the direction race chains go. In the other extreme of an obtuse hook angle the chain can become more prone to bouncing out of the cut. this can be very dangerous and this it is one more consideration of why milling chain should only be used for milling.

Andrew touched on how a chain can be tailored to optimise the power of the saw. This is can be true but I still run my rakers at .035" with a hook of around 50*. I am however runing this on an 075 which has the torque to pull this combo and by going to the deeper rakers I can gain a bit of cutting speed that I lack in rpm's.

 

[Andrew96]

There is no "perfect" cutter, only approximations to it. It's always a trade off between speed and durability.

That's what I didn't know. I thought there was a 'perfect' cutter if I did enough research to find all the proper numbers, then used some solid techniques to get consistant and accurate dimensions.

a real high end grinder can get you consistency on tooth size and raker height, but can't do anything with the natural compromises of cutting angles, except make the compromise consistent.

Of course any grinder or filing guide cannot alter the compromise in the geometry you choose.....I kind of thought I would be able to make a nicer job of a cutter with a good quality guide when compaired to a grinder (the one fact....no grinding heat on the cutter!). Of coures, I'd spend more time doing it..... Fair assumption?

Bluerider....

In the other extreme of an obtuse hook angle the chain can become more prone to bouncing out of the cut. this can be very dangerous

I understand this....yes, that would be dangerous having a cutter that required pressure to keep it cutting.

and this it is one more consideration of why milling chain should only be used for milling.

I assume you mean..."any" chain ground to such an obtuse hook angle that it doesn't even self feed, is not good for any cutting, never mind milling. However, I cannot see why I would need milling chain (currently I don't have any).
From what I gathered, milling chain has different top plate geometry. With the top plate angle at 10deg, not 25-35deg, to minimize the side forces on the cutter...giving less clearance in the kerf, and create a better finish. The drawback to milling chain...the low cutting angle (top plate) would require more power to pull through the cut....it still has the inherient hook angle comprimise (since I now know...there isn't just one proper angle).

So I bet my cutter has more hook than a stihl factory one. Mine are nice and sharp...seem to last a long time, throw nice chips...BUT are not as smooth feeling while cutting. Hmm....so you think hook angle is the key? You say less grabby...I find out that means not as smooth vibration wise during a cut.

 

[BobL]

From what I gathered, milling chain has different top plate geometry. With the top plate angle at 10deg, not 25-35deg, to minimize the side forces on the cutter...giving less clearance in the kerf, and create a better finish. The drawback to milling chain...the low cutting angle (top plate) would require more power to pull through the cut....it still has the inherient hook angle comprimise (since I now know...there isn't just one proper angle).

So I bet my cutter has more hook than a stihl factory one. Mine are nice and sharp...seem to last a long time, throw nice chips...BUT are not as smooth feeling while cutting. Hmm....so you think hook angle is the key? You say less grabby...I find out that means not as smooth vibration wise during a cut.

Reducing your top plate filing angle will make the cutting smoother.

 

[oldsaw]

That's what I didn't know. I thought there was a 'perfect' cutter if I did enough research to find all the proper numbers, then used some solid techniques to get consistant and accurate dimensions.[/quote

Again, it's a balance. A miller needs a more durable cutting edge, a racer really wants speed, so the chains are filed differently. The thinner profile cutting edge on a racing chain will blow through a log in no time flat and throw huge chips. Outside of a few short cuts, durablility isn't that important. That's why race chains don't work in the field either.

Of course any grinder or filing guide cannot alter the compromise in the geometry you choose.....I kind of thought I would be able to make a nicer job of a cutter with a good quality guide when compaired to a grinder (the one fact....no grinding heat on the cutter!). Of coures, I'd spend more time doing it..... Fair assumption?

A high quality grinder will give you consistency that a guide can't give you. Not saying you can't get excellent results from a guide and sharp file, but it can't give you the accuracy of the grinder. When done correctly, the grinder will not burn your teeth or hurt their durability. That's the way the factory does it.

 

[AaronB]

Counting strokes is ok for touching up but you do have to at some stage actually measure the lengths of the cutters, usually after every few days milling is when I do it.

Once I settled on my working cutter parameters, I'm not all that concerned about them being too exact. I try to get raker depths within 0.005", cutter lengths within 0.010".

Is there a difference in using a caliper vs micrometer when measuring the teeth, as you had in step 3. I don't own a micrometer so I am not sure how they work, so that's where this comes from.

 

[mtngun]

Is there a difference in using a caliper vs micrometer when measuring the teeth, as you had in step 3. I don't own a micrometer so I am not sure how they work, so that's where this comes from.

Caliper is fine for measuring lengths.

 

[Andrew96]

A high quality grinder will give you consistency that a guide can't give you.

Thanks for your comments Oldsaw. I guess I'll have to revisit the high quality grinder again ...research the choices available for ones that fall into a the 'high quality' category. I like accuracy and consistancy...but of course would need to pick the best one for me.

 

[excess650]

I'm assuming a 3/8 chiain? For the first half or so of the tooth you might want to use the 7/32" file and then go to 13/64" as the tooth gets shorter. Stihl specs 13/64" on their 3/8" chains.

I have a cheapo file jig, but it works pretty well. The Granberg appears to be more substantial. Generally, I touch my chain up by eye, and save the grinder for straightening, evening things up after its been hand sharpened many times., or has been rocked.:censored:

Often times I'll touch up my milling chain while the 36" Alaskan is still attached. One side gets filed fromt he inside, and the other from the outside. Filing from the outside doesn't leave a burr.

 

[BobL]

Often times I'll touch up my milling chain while the 36" Alaskan is still attached. One side gets filed fromt he inside, and the other from the outside. Filing from the outside doesn't leave a burr.

I can easily touch up my chain on the mill. I have this nice table that I lay the mill over on its side as shown and then clamp it to the table.

Filing the cutters facing away from underneath is dead easy - I even sit down to do it.

Filing the other side is little trickier but the long tubular handle that runs the full length of the mill is sufficiently far enough away from the bar for me to get access from the top/side of the mill. To file the other side I stand behind the mill in this photo and lower my chest onto the tubular bar and the left arm goes over the top and the right one comes up from underneath to hold the file. I sounds awkward but it is quite a comfortable position to touch up from.

 

[stipes]

Pic #6....

I have the Granberg File-n-joint but have some questions about filing in general. Per the Oregon box I am to use a 7/32 file, which I did.

My question is how to you know how high the file is to be above the cutter. I have read 1/5 or 1/10th of the file above the tooth, but when I set the file to what I think that is, based on pictures I have seen, the file makes a 'dip' in the gullet.

I didn't think having that dip was correct, so I raised the file up so the gullet would have the flat bottom that it does now, or at least real close to flat. So any suggestions or pictures/illustrations that you guys have the would help me on how the file sits in the tooth. I did see some pictures but for the file to sit the way they showed it it would have to be a smaller file.

Anyway, here is some pictures of the setup and of some teeth I did. Let me know if you see any major issues. The last four I think are the way it should look after sharpened, but I have never done it, so I am not sure.

Thats the type of hook I like...For me cutting tru dirty red oak if I get too much hook,,it wont last long till ya have to sharpen....Not enough hook,,you'll spend most of your time pushing...I think your really,,close on this....I'd run that chain!!!

 

[DRB]

Just thought that this maybe of some interest to some of you that use a file-o-pate. Pages 18 to 20 were interesting to me.

http://www.baileysonline.com/PDF/carlton_fileoplate.pdf

I did not know that the cutter tooth tipped back while in the cut? If this actually happens then this explains why I have always been able to make a chain cut till the teeth are gone. I have seen half worn chains that friends have told me would not cut so they buy a new one. I have always use a file-o-plate to set raker depth but did not know about progressive raker depth.

Just thought that this fit into this topic.

 

[BobL]

Just thought that this maybe of some interest to some of you that use a file-o-pate. Pages 18 to 20 were interesting to me.

http://www.baileysonline.com/PDF/carlton_fileoplate.pdf

I did not know that the cutter tooth tipped back while in the cut? If this actually happens then this explains why I have always been able to make a chain cut till the teeth are gone. I have seen half worn chains that friends have told me would not cut so they buy a new one. I have always use a file-o-plate to set raker depth but did not know about progressive raker depth.

Just thought that this fit into this topic.

It sure does - huge gory details about FOPs (and some of their possible small failings) here http://www.arboristsite.com/showthread.php?t=114624

 

[DRB]

Now your hurting my head I will have to abandon the family and and read up on my chain sharpening. I just spent the last 2 days in the shop correcting all my field sharpened chains. Correcting a 50" bar chain with calipers by hand takes quite awhile. I am fairly happy with the way my chains cut but always looking for a better and faster cut.

Thanks for the info Bob

 

[Andrew96]

I too have been reading too much about sharpening, angles, wear. I recently found out I was inadvertantly doing it wrong (hook angle a bit much)....and I need (OK I want) a grinder to get more repeatability and consistancy.

What I cannot quantify is the chain tension adjustment. I think it would affect the porpoising that the cutter does during a pass through the wood.

This past summer I learned that the cutter 'dives' into the wood. Tips in if you would.

My assumptions here:
In order to do this..it's needs some slack in the chain. Bigger bars need more slack as more cutters need to be tipped in along the length of the cut (I assume more than one is cutting at any given time). Now I understand that the rakers only allow the cutter to tip so much...but if the chain tension itself is too high...or rather not loose enough...wouldn't all this tipping up, porpoising use up all my slack and bind..loosing power? Possibly impeding multiple cutters from tipping up?
Since I'll confess I don't know what the h*&% I'm doing.....Has anyone hung a weight off a properly tensioned chain and measured the deflection? It's how you set anything tensioned repeatedly. Around here everyone has worked over all of the geometry for the cutters. I would think chain tension has an important role....deserves more attention than I've given it.

 

[mtngun]

I need (OK I want) a grinder to get more repeatability and consistancy.

I have better luck with a grinder, but many swear by filing. Either way, there is a learning curve. It took me about a year to get good results with the $30 chinese grinder. It may take me another year to master the Jolly Star.

I can touch up a chain with a file in between grindings, but it's nice to rely on the grinder to restore consistent angles and lengths.

What I cannot quantify is the chain tension adjustment. I think it would affect the porpoising that the cutter does during a pass through the wood.

I believe the side of the bar that is doing the cutting will be in tension, because the saw is pulling it through the wood. The slack will be on the opposite side of the bar.

If a chain is too loose, it is prone to derailing. If a chain is too tight, it creates excess friction. My rule of thumb is to snug it up until the drivers are inside the bar, yet loose enough that I can grab the chain and pull it away from the bar.

Andrew, you worry too much. As you spend more time milling and playing with saws, you'll gradually find techniques that you are comfortable with.

The only urgent issue, IMHO, is to learn to tune your saw a little rich so you don't burn it up.

A while back we had a member who had just started milling, and like many newbies, he was using a mid-sized saw, a new MS361 if I remember correctly. He assumed the dealer had tuned it correctly and then proceeded to fry the new saw while milling. So ya gotta learn to tune your saw. No hurry on the other stuff.

 

[BobL]

If a chain is too loose, it is prone to derailing. If a chain is too tight, it creates excess friction. My rule of thumb is to snug it up until the drivers are inside the bar, yet loose enough that I can grab the chain and pull it away from the bar.

Yep, the bottom of the ties should just make contact with the bar. Then spin the chain and check the tie strap bottoms are still making contact.

 

[Andrew96]

OK, so I've been doing the chain tension correctly all along. It can't hurt to ask....It's these longer bars and the way the cutter cuts that got me thinking. I've been hand filing chains for a long time..... back in the day when my Dad told me I had to learn to sharpen a saw before I could cut with it.

It's not that I worry so much about stuff...just don't want to miss some little detail when I have so many experienced people around here. You can read old posts for hours and still learn stuff.

The only urgent issue, IMHO, is to learn to tune your saw a little rich so you don't burn it up.

Well...that's the least of my problems. I'm confident in is setting up the saw to run rich under load. It's ruch but I also did a plug chop just to make sure. Very good point though. If others don't understand, you could ruin a nice machine quickly.

 

[BobL]

Now your hurting my head I will have to abandon the family and and read up on my chain sharpening. I just spent the last 2 days in the shop correcting all my field sharpened chains. Correcting a 50" bar chain with calipers by hand takes quite awhile. I am fairly happy with the way my chains cut but always looking for a better and faster cut.

Thanks for the info Bob

No worries, I just posted more geeky sharpness ideas on the Chainsaw FOP sticky - see here - http://www.arboristsite.com/showthread.php?t=114624