Cutters the same length

Gary_C · August 03, 2005, 09:47:29 PM

I have the Oregon standard sharpener and sharpen a lot of .404 harvester chain. I have always noticed if you keep the same settings for both left and right cutters, they do not look to be the same length. The cutters closest to you as you sharpen look shorter. It probably does not make much difference after the first sharpening, but I always believed it was best to keep the cutters the same length. A guy that worked in a local saw shop told me once they used a different angle for one side but that doesn't seem right to me.

Should I compensate for this difference or just not worry about it?

Oregon Engineer · August 04, 2005, 10:55:28 AM

What's the part number on the sharpener? If you have a caliper, measure the difference between the cutters and let me know.

SawTroll · August 05, 2005, 04:57:52 AM

If that condition was on a saw chain, it would start cutting crooked sooner or later.
I don't know anything about harvesters, though.

Gary_C · August 05, 2005, 10:38:14 AM

The sharpener is a Model 511A. The cutters are .025 longer on the right side which is the side closest to me when I sharpen the chain.

I first noticed it when I first sharpen a new chain. If you start on the right side, it grinds too much off when you switch to the left side. After that first sharpening, the amount taken off is the same on both sides, but the right side remains .025 shorter.

jokers · August 05, 2005, 12:53:54 PM

Gary,

What you are seeing is almost universally true with all models of grinder which have a pivoting head. The problem also magnifies as the diameter of the wheel decreases. You can compensate to a certain extent by how you center the chain vise under the wheel but I don`t have a tried and true method for you. Trial and error I suppose.

What works for me is to first completely grind the side with the most apparent damage, then swap to the other side, starting long and working my way down to where the teeth are even from side to side. To check for equal length from side to side, just fold the chain in your hand with the backs of two opposing cutters against each other. Grind accordingly until they are even.

You could also invest in a Borazon wheel which will not lose diameter through use and then do a painstaking initial setup. Over the long haul the borazon is cheaper but the initial investment is higher than most home shops or shadetrees are willing to make.

Russ

Russ

Oregon Engineer · August 05, 2005, 03:06:40 PM

Gary,

If you are cutting smaller diameter trees (under 18") you will not notice the .025" difference between right and left hand cutter lengths. As the tree diameter goes up so does the likelihood of getting a leading cut. Harvester bars will lead off a bit and then jam in the cut where a hand operator will adjust to the lead and finish the cut.

For 18H chain on a 511A, I usually have to move the center of the rails towards the operator by .030 with a new grinding wheel. Otherwise the right hand cutters are shorter.

Take a length of chain just for setup purposes. Put the chain in the vise and pull the chain back against the stop each time with equal force. Grind two or three cutters on both sides, measure the average difference. If the right hand cutters (closest to you on a 511A) are shorter than the left hand cutters then adjust the rails so they move closer to you (away from the back of the grinder). If the right hand cutters are longer then move the rails away from you (towards the back of the grinder).

The adjustment for moving the rails on a 511A grinder is a small allen screw and lock nut located on the back of the grinding vise. Please see the picture that shows an allen wrench being inserted into the screw.

You may need to loosen the two allen screws, one at each end of the rails, so the chain will have the clearance to slide through the rails after adjusting the rail centering allen screw.

Joker is correct, grind the cutters with the most amount of damage first. For a harvester it is usually the side of the chain closest to the ground because they hit the rocks first. Joker is also correct that the rails need to be adjusted as the grinding wheel diameter changes.

If you switch between .063 (16H) and .080 (18H) chains then the rails will need to be readjusted each time.

What type of chain and what type of harvester head are you operating????

donbingham · August 05, 2005, 04:46:56 PM

Oregon Engineer, I have noticed that some slightly higher priced sharpeners, i.e. Bellsaw, have a switch to reverse the rotation of the grinding wheel so that the wheel is always approaching the cutter from the same direction. It seems to me that this might have some effect on the amount that opposite cutters are ground as well as always grinding into the chrome from the same direction. My question is do you think it would be worthwhile from me to wire up a reversing switch to my Oregon grinder? I am not asking for a company position and know that I would void the warranty which is of no concern to me. I haven't checked to see if the motor is of a type that I can reverse. On the other hand I have the grinder but do not use it. I sharpen by hand with a Pferd filing device that has two files and sharpens the cutter and depth gage at the same time.

Oregon Engineer · August 05, 2005, 06:32:51 PM

Donbingham,
The reversing switch is used to keep the grinding burr on the inside of the cutter side plate and off the chromed outer surface. When the burr breaks off the chromed side it can take a very small amount (around .001") off the side plate.

The advantage gained by keeping the burr always to the inside of the cutter (ie. having a reversing switch) is outweighed by the hazards of wheel bursts and grinding debris thrown into the eyes and lungs.

High speed video work done on wheel breaks (even with the proper guarding installed) show it is safer to have the wheel rotating so the debris is directed away from the operator.

Look at the back of a grinder and you will see a cone shaped pile of debris, way better to have that debris on the grinder than in your eyes or lungs.

Hard to use a chain saw if you can't see or breathe.

Please don't alter the grinder, you won't notice a difference in performance but you do increase your risk of eye, face and lung injuries.

Gary_C · August 06, 2005, 01:09:48 AM

Oregon Engineer

I have a Valmet 546H with a 960 head. I am using the Oregon 18H087E chains on the wide belly bars with a 13 tooth drive sprocket. I may have to switch back to the 12 tooth sprocket because it is very difficult to put a new (non stretched) chain on the bar.

I am just finishing a first thinning of a pine plantation so there is nothing over 8 inches. However in about a week I will be starting a job with over 600 cords of hard maple pulp along with 100 MBF of Red Oak, Sugar Maple, and Basswood saw logs. I generally do not cut Oak or Maple trees over 14 inches with the harvester unless they are low quality. I sure don't need a chain that will not cut straight and there is some blowdown to be cut up and that is going to give the sharpener a workout.

Thanks for the information. I am about ready to put on a new wheel so I will change that and check the cutter lengths and adjust from there.

Thanks

Gary

Oregon Engineer · August 12, 2005, 02:38:28 AM

Gary,
Are you going to the Lake States Logging Congress in Marquette, MI during early September???

Gary_C · August 12, 2005, 11:50:37 AM

Oregon Engineer

No, it is just too far and I have a large job that has to be done by late October. I did get to last year's show in Green Bay only because I had to look at a trailer.

I may try to get to the "North Star Expo" in Grand Rapids, MN on September 16-17, but even that is not for sure.

On this subject of cutters, I was checking all my settings and found the box that the chains comes in has a setting for side plate angle of 80 deg while the insert in the box shows side plate angle of 85 and top plate cutting angle of 60 deg. So what do I set my top head angle at on the grinder?

Dan_Shade · August 12, 2005, 01:03:38 PM

I grind all the teeth on one side, then I check the length of the teeth with a caliper, then reset the stop and grind all the teeth on the other side. the instructions are not the clearest on how to set it up, i may give the adjustment another spin next time I have it out.

Oregon Engineer · August 12, 2005, 04:47:15 PM

Gary,
The back of the chain box has the correct settings. The insert put into the box with 4 langauges is being revised to match the information on the back of the box. The grinder head should be set to the 60 degree mark for 18H to get the proper top plate cutting angle.

Drop me a personal message with your address and I can send you the Mechanical Timber Harvesting Handbook which has a lot of information on issues common to harvester chains/bars/sprockets.