Chainsaw milling novice- cut not running straight, chain sharpening issue?

[Layne]

Hi everyone,

I've read threads on here numerous times and they've been incredibly helpful so thankyou all for that. I'm just starting to do a lot more chainsaw milling so that felt like a great time to join and be able to ask for guidance as there's a lot for me to learn for sure.

I've been working with my Granberg small log mill for the last couple of days, using an MS 241c with an 18" bar and granberg milling chain. I bought the chain new earlier in the year and milled a couple of dozen larch boards for cladding, so it was time to give it a first sharpen before using it again this time. To do that I've just bought the granberg 12v precision grinder and a diamond file from Rob at chainsawbars. So I got it set up and had my first go using it - after a couple of tries the chain was cutting pretty ok I thought so I headed off to the woods to mill some larch trees around 11" in diameter in 3m lengths.

The first day milling yesterday went ok, the cuts were running straight and producing nice boards. Towards the end of the afternoon it felt like the milling was quite slow so I timed it and it was taking me around 20-25 minutes to mill one board, refuel (the saw was getting through a tank per board) and get going on the next one. Since I'm new to milling I don't have many references yet but that seemed a bit slow to me and I felt like I was pushing on the saw harder than felt optimal so I decided this morning to give the chain another light sharpen on the grinder and headed off again to do more milling. I'll attach photos of what I'm describing so hopefull that will help you all to see what I'm trying to explain.

With the first (top) cut the saw started to struggle and take some pushing through around halfway along the log, and was clearly getting hot, so I took a step back to have a look what might be going on. I discovered that the cut had ran off line and was diving deeper into the log (see photo), so no wonder the saw was struggling. I had a look online for what the problem might be and found a post somewhere with 3 suggestions- the chain was not sharpened correctly, the bar might have burrs or be bent. So I took the saw to the workshop and found that the bar did have burrs on it, slightly more on one side but there were some on both, and the bar had a little wiggly bend on it (at around the point where the mill screws onto the bar). So I files off the burrs and straightened out the bar to pretty straight. Since the first cut had ran straight for the first metre and the cuts were running straight yesterday, I didn't resharpen the chain and went to a new log to try again. This time I found that the saw became hard work to move through the log within the first few inches of the cut. When I stopped and took a look I could see that the cut in the log was again veering off downwards (see photos - I've held a tape measure to extend the line so the angle can be more clearly seen). I also took some photos of my setup at this point with a tape measure held up in a couple of them to try to see if the saw was somehow not lined up straight in the mill - it seemed to be ok to me.

At this point it felt like my issue might be more with the chain sharpening, so I headed back to the workshop. As a further test I took the mill off the saw and stood a firewood log on end and cut through it to see if the cut ran true. It curved off increasingly to one side and exited the log partway down (see photo). 

So this leaves me with a few questions I'd appreciate any advice on:

- was my chain poorly sharpened the first day to be cutting at the speed described above? I've also attached a photo of the sawdust, which is definitely fine and not like the large strands I get when using ordinary chain for general tree work. I couldn't remember what the sawdust had looked like when the chain was new so I went to the site of my first milling and that too looked pretty fine.

- what do you think is the most likely problem causing the cuts not to run straight?

- if it's the chain sharpening, would this be due to the teeth not being exactly the same length (I've measured a few and they are pretty similar but not all exactly the same) or something else?

- does anyone have any tips for using the precision grinder? I've watched a few videos on youtube including one from Rob to get started.

 

Apologies for the slightly random order of the photos below, this is my first post and I'm just figuring out how to sequence them properly.

 

Any replies would be much appreciated, thanks for reading this..

 

[trigger_andy]

Hello and welcome.

 

The main issue with the Granberg Grinder is when you grind one set of teeth at say 10 degree's (or 30 if cross cutting) is you cant always just swing the Grinder from one set of 10 degrees to the opposite and expect the cutters to be the exact same length. So when I use it I do one set of teeth then swing it around for the other set of Teeth, grind the first tooth then measure with a vernier caliper then adjust the Granberg Precision Grinder to suit. See step 5 in the picture below;

 

Its not easy to see in your picture of the chain, but to me it looks blunt. 

 

I see you've taken the rakers down, but its hard to see if you've taken them down to the correct depth. In the Granberg Instruction manual it shows you how to set the Percision Grinde up to take the rakers down and how many 'clicks' of the height dial and setting the cutting angle to 0 degree's. You can use this in conjunction with a depth gauge or follow the instructions in the instruction manual, Ive added the section in the secon picture, the section is called 'Jointing depth gauges'

Edited August 25, 2021 by trigger_andy

[AJStrees]

1 hour ago, Layne said:

Hi everyone,

I've read threads on here numerous times and they've been incredibly helpful so thankyou all for that. I'm just starting to do a lot more chainsaw milling so that felt like a great time to join and be able to ask for guidance as there's a lot for me to learn for sure.

I've been working with my Granberg small log mill for the last couple of days, using an MS 241c with an 18" bar and granberg milling chain. I bought the chain new earlier in the year and milled a couple of dozen larch boards for cladding, so it was time to give it a first sharpen before using it again this time. To do that I've just bought the granberg 12v precision grinder and a diamond file from Rob at chainsawbars. So I got it set up and had my first go using it - after a couple of tries the chain was cutting pretty ok I thought so I headed off to the woods to mill some larch trees around 11" in diameter in 3m lengths.

The first day milling yesterday went ok, the cuts were running straight and producing nice boards. Towards the end of the afternoon it felt like the milling was quite slow so I timed it and it was taking me around 20-25 minutes to mill one board, refuel (the saw was getting through a tank per board) and get going on the next one. Since I'm new to milling I don't have many references yet but that seemed a bit slow to me and I felt like I was pushing on the saw harder than felt optimal so I decided this morning to give the chain another light sharpen on the grinder and headed off again to do more milling. I'll attach photos of what I'm describing so hopefull that will help you all to see what I'm trying to explain.

With the first (top) cut the saw started to struggle and take some pushing through around halfway along the log, and was clearly getting hot, so I took a step back to have a look what might be going on. I discovered that the cut had ran off line and was diving deeper into the log (see photo), so no wonder the saw was struggling. I had a look online for what the problem might be and found a post somewhere with 3 suggestions- the chain was not sharpened correctly, the bar might have burrs or be bent. So I took the saw to the workshop and found that the bar did have burrs on it, slightly more on one side but there were some on both, and the bar had a little wiggly bend on it (at around the point where the mill screws onto the bar). So I files off the burrs and straightened out the bar to pretty straight. Since the first cut had ran straight for the first metre and the cuts were running straight yesterday, I didn't resharpen the chain and went to a new log to try again. This time I found that the saw became hard work to move through the log within the first few inches of the cut. When I stopped and took a look I could see that the cut in the log was again veering off downwards (see photos - I've held a tape measure to extend the line so the angle can be more clearly seen). I also took some photos of my setup at this point with a tape measure held up in a couple of them to try to see if the saw was somehow not lined up straight in the mill - it seemed to be ok to me.

At this point it felt like my issue might be more with the chain sharpening, so I headed back to the workshop. As a further test I took the mill off the saw and stood a firewood log on end and cut through it to see if the cut ran true. It curved off increasingly to one side and exited the log partway down (see photo). 

So this leaves me with a few questions I'd appreciate any advice on:

- was my chain poorly sharpened the first day to be cutting at the speed described above? I've also attached a photo of the sawdust, which is definitely fine and not like the large strands I get when using ordinary chain for general tree work. I couldn't remember what the sawdust had looked like when the chain was new so I went to the site of my first milling and that too looked pretty fine.

- what do you think is the most likely problem causing the cuts not to run straight?

- if it's the chain sharpening, would this be due to the teeth not being exactly the same length (I've measured a few and they are pretty similar but not all exactly the same) or something else?

- does anyone have any tips for using the precision grinder? I've watched a few videos on youtube including one from Rob to get started.

 

Apologies for the slightly random order of the photos below, this is my first post and I'm just figuring out how to sequence them properly.

 

Any replies would be much appreciated, thanks for reading this..

 

From past experience (which is not as much as many on here) but I have had some. Teething problems I had as a novice miller. I have attempted to explain this simply so hopefully you get what I am meaning. 

 

00. It is hugely important to make sure your chain is perfectly sharp and it goes without saying, definitely a well sharpened chain will be the first thing to look at. 

 

0. the straight edge bar one uses on top does need to remain straight while cutting. I normally use a metal ladder and this bends and moves very little if at all. 

 

1. In the past I found that the cross bar on the mill was slightly off on one side due to a nut that was not properly tightening up, this led to the mill becoming wedged between the straight edge on top of the log and the chainsaw bar and the cutting became increasingly hard to do. I took the mill apart and put it back together with a better nut and this solved the problem. 

 

2. On another occasion I was using a lo pro bar and after some time milling with it the teeth on the sprocket nose had broken off and the bearings inside the nose has jammed into one side of the sprocket nose, this started to make the cutting uneven. It was not obvious that there was a problem until I took the chain off. The bearings on the lo pro bar were particularly small so it did not seem obvious until I took the mill and saw apart. 

 

I learned these points the hard way. Potentially if there was a course and a troubleshooting manual for milling, life would be more simple. In the meantime you can always read the Will Mallof book on milling and get some advice from millers on here. 

Edited August 25, 2021 by AJStrees

[trigger_andy]

You should also remove all the burned on sap off of the top of the cutters each time you sharpen as well. Thats not gonna help your cutting at all You're pushing the cutting edge away from the Log you're milling and just generating more and more heat. 

[Doug Tait]

If I understand your post correctly, it makes me wonder if you hit metal.

 

It was cutting well from new, and after the first sharpen. When you noticed it struggling you found bar damage which you sorted but didn't sharpen chain again and got no improvement in performance. It could be that you've cut a foreign object.

[openspaceman]

1 hour ago, Layne said:

 

Any replies would be much appreciated, thanks for reading this..

The above chain is blunt

[Layne]

Thanks tigger andy - I'm pretty sure I didn't get an instruction manual with my grinder, I'll double check that in the morning and find a way to get hold of one so that's really helpful.

I heard a guy on a youtube video say about the dial and how many clicks to lower it. I was really surprised how much it took off though, I felt like I might have just ruined a chain when I ground the first one down. I backed off a bit from doing three clicks as a result and about halved that for the rest of them.

How do I remove the burned on sap? I wondered about that.

 

Thanks AJStrees, I'll look over the mill for any potential misalignments anywhere. I used a ladder before, and have been using one with our 48" Panther horizon mill I've also been learning to use recently. The length of 6x2 has seemed to work pretty well when I've used it though I did notice the potential for it to bend when being screwed to the log today. Does everyone think a ladder is the better way to go?

I've got the Will Mallof book, working my way through that at the moment.

 

Thanks Doug - I didn't notice catching anything while cutting.

 

Thanks openspaceman. I'd like to get really profficient at being able to see when a chain is sharpened well. A friend mentioned today about a jewellers bit of kit he was using to inspect the edge on a knife he was sharpening - that sounded worth finding out about. How do you tell - just by eye or by taking a photo/anything else?

[Layne]

Does the sawdust look ok to you guys? Did I get it reasonably sharp? It did seem slow going to get through a log when it was cutting straight, but I believe the MS 241c is slightly underpowered for the small log mill?

[Layne]

@ tigger andy I've been trying the method used on the granberg instructional video for the precision grinder to measure the tooth length - a bolt with a couple of nuts attached which are adjusted to set the measure. Is it worth me getting a vernier caliper? I'm just getting a sense of how accurate this all has to be, is it a case of the more accurate the better?

[trigger_andy]

Just now, Layne said:

Does the sawdust look ok to you guys? Did I get it reasonably sharp? It did seem slow going to get through a log when it was cutting straight, but I believe the MS 241c is slightly underpowered for the small log mill?

The Precision Grinder when used correctly gets the teeth razor sharp. But when you have what looks like a rounded over leading edge like in your pic then just taking a 'kiss' off the tooth is not gonna do anything. For such a small chain Id only use the Precision Grinder if I'd have hit metal, its simply not needed for a quick re-sharpen. But with your chain as blunt as it looks then try taking a bit more meat off the tooth with the Precision Grinder and then make sure you're taking the same off the other side with a vernier caliper. Once you're all square again then when you empty the tank of fuel or two give the chain a few licks with a hand file. Just count how many you give each tooth and make sure they all get the same. Then every few sharpens check the rakers with your Depth Gauge, you do have one, right?  

 

As for the sap, a screwdriver or better yet the file you have for taking down the rakers will soon get rid of that.