Granberg G-106B Chain Sharpening Questions

[clarksvilleal]

I have a Granberg G106B sharpening jig. I have sharpened several Oregon 20LPX chains with it, but I am confused about one of the angle settings, and also have a question about cutter lengths.

First, the Granberg instructions say that you should set the tilt dial to zero and the filing angle to the mfr. specified filing angle, e.g., 25 degrees for the Oregon 20LPX chains I am using, before beginning to sharpen the cutters. But the Oregon chart also shows an angle (designated "B" in their chart) of 10 degrees, which appears from the picture at the top of the chart to correspond to the tilt angle.

So my question is do I set the tilt angle to 10 degrees as Oregon shows,or to zero as the Granberg instructions specify? I have just sharpened 4 chains with the Granberg tilt angle set to zero, and used one of them today. It appeared to cut very well. But I want to be sure I am doing it the best way possible.

The second question is more of a general question about cutter length. The Granberg instructions agree with other sharpening instructions I have read that say that all of the cutter should be sharpened to the same length. Granberg says to start with the shortest cutter and set the tooth length gauge accordingly so that all of the cutters will end up the same length as the shortest cutter after sharpening. I understand that in principle this is correct. However, a couple of my chains had a small number of cutters - 2 or 3 - that were damaged from hitting metal objects embedded in logs. In order to sharpen the damaged cutters well I had to remove a large amount of the cutter - maybe 1/4 to 1/3 or so. I did not want to remove that much of every cutter just to make them all equal length. Not only would it be very time-consuming, but it would also shorten the life of the chain. So I removed enough tooth from the damaged cutters to completely eliminate the damaged part. Then I sharpened all of the other cutters much less - though I did sharpen them all to the same length. As far as I could tell in cutting logs today there doesn't seem to be any problem with a few short cutters on the chain.The chain cut just fine. So how critical is the equal cutter lengths, and what problems could arise when cutting with a chain that has different length cutters?

 

[2dogs]

The G-berg sharpening jig is a great tool. The angle and tilt you choose are what fits your chain and your cutting conditions. For my use with square ground chains I sharpen at 10 degrees up and a 25 degree cutter angle. With semi-chisel I sharpen at 0 degrees tilt and a 35 degree cutter angle. Use what works for you.

 

[Currently]

Perfection costs a
lot of money with little
return on results.

Common sense dictates a couple of damaged teeth will have a marginal impact on the overall chain performance. A whole side will have major impact.

I keep damaged but re-sharpened chains in a separate Tupperware container for crappy jobs that I know will kill a chain.

 

[ErrolC]

Agreed...a couple of teeth won't hurt...a test'll tell you...better to cut the affected cutters out & re-rivet a couple of new ones in than to grind/file them all back...you'll be able to get some new cutters from you shop (they'll have a heap in a tray from left overs for a buck or 2) if you don't have a roll on hand!

 

[clarksvilleal]

The G-berg sharpening jig is a great tool. The angle and tilt you choose are what fits your chain and your cutting conditions. For my use with square ground chains I sharpen at 10 degrees up and a 25 degree cutter angle. With semi-chisel I sharpen at 0 degrees tilt and a 35 degree cutter angle. Use what works for you.

Sorry for such a dumb question, 2dogs, but I am still obviously a novice: is my Oregon 20LPX chain semi-chisel or square ground chisel? There is nothing on the box that the loop came in that specifies which it is. However the angles are given for 20LPX filing are 25 degrees cutter angle and 10 degrees up, so does that mean it is square ground chisel?

 

[clarksvilleal]

Agreed...a couple of teeth won't hurt...a test'll tell you...better to cut the affected cutters out & re-rivet a couple of new ones in than to grind/file them all back...you'll be able to get some new cutters from you shop (they'll have a heap in a tray from left overs for a buck or 2) if you don't have a roll on hand!

What tool or tools do I need to cut out and re-rivet cutters. I imagine I will have a chain at some point that is so damaged that it would make sense to cannibalize it for the good teeth.

 

[Thomas Venditto]

I'd do what you said. File the broken teeth separately. Someone may want to correct me, but the shorter teeth will basically be doing nothing until the rest are as short. Therefore, you're making a skip chain until that time comes.

 

[sundance]

Sorry for such a dumb question, 2dogs, but I am still obviously a novice: is my Oregon 20LPX chain semi-chisel or square ground chisel? There is nothing on the box that the loop came in that specifies which it is. However the angles are given for 20LPX filing are 25 degrees cutter angle and 10 degrees up, so does that mean it is square ground chisel?

20LPX is a .325 x .050 chisel chain, not a semi-chisel. Note that square chisel terminology would normally indicate a square ground chain (whole different animal). A Granberg to my knowledge will not sharpen a true square ground chain. It will do fine with chisel or semi-chisel chain.

I would address the damaged cutters the same way you have. Changing out cutters would require a breaker and a spinner. Then you end up with a couple long cutters which will be a bigger issue than a couple short ones (pretty much need to file back to match).

For myself, I typically just sharpen the same number of strokes on each tooth without trying to find the shortest cutter and match all to it. Haven't had much problem with this approach. If something gets well out of whack I'll work to correct it.

 

[clarksvilleal]

Thank you, Thomas and Sundance. So I'll continue as I have, cutting most to the same length except for the damaged ones which I grind shorter, as you both have also confirmed does not seem to cause any problems.