Chain Grinding Technique

[Engineeringnerd]

I've been grinding chains for about 4 months now using a MAXX grinder. I found the process a little more delicate than I first expected, finding that if I get in a rush I can easily blue the teeth and even ruin the chain. I can avoid heating the chain so much by barely touching the chain with the wheel and taking the time to make several rounds, allowing the teeth to cool between hits. Certainly keeping the wheel clean helps.

Recently, almost by accident, I found another technique that seems to work very well and allows me to sharpen the chain quickly in a single pass, but may be a little unorthodox. Here goes:

1. Set up the grinder to the correct depth and set the chain pawl so the wheel just barely touches the tooth on its way down.

2. With the grinder in the full down position, gently side load the grinding wheel into the tooth, using about 5 pounds of pressure.
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What I've found is that even though the MAXX's pivot is quite tight, the arm extends out 12-16" and the side loading flexes the arm slightly and pushes the wheel into the tooth another 0.020 - 0.030 or so (guessing). So far I've found the technique to provide an amazing edge without introducing so much heat into the top of the cutter, which can curl the edge or cause the edge to blue. I don't know if this technique just spreads the heat evenly over the whole tooth in a short burst, essentially using the tooth as a heat sink, or if it simply reduces the grinding time normally experienced by the top of the cutter. Traditionally the top edge of the cutter is actively being ground from the first engagement of the wheel until the wheel is raised off the cutter.

I don't feel I'm stressing the grinder's arm and pivot much at all, so I'm not very concerned about ruining the bearing or trashing the arm. I also wouldn't expect the side loading on the wheel to provide much stress on the motor bearing as the action is very slight. The motor itself barely slows during the process, so I'm not overburdening the motor itself.

For context I'm grinding 72LG, 72DP, 30RC, 30RCS, 20SC, 30SCS, 20NK, and 95VP chains.

Feedback?

 

[Engineeringnerd]

TreeCo,

How much "float" or movement does your square grinder provide for the grinding operation?

 

[IchWarriorMkII]

Nice post... anyone try/use this method?

Seems like it should work well... makes me want to get a grinder :chainsawguy:

 

[Gypo Logger]

Your technique is similar to the way I grind. A light touch is the way to go.
Also, wheel modification is important. Since only one side of the wheel does the grinding, dress that side only and dress the bottom of the wheel flat.
A good carborundum dressing stone from a tool and die maker is much better than the ones that come with the grinder.
It's also a good idea to make sure the L & R cutters are equal, as there is a set screw in the vise for that.
John

 

[Patrick62]

Kinda like that

I use both sides of wheel, and flip it often to wear it evenly. Also keep it profiled "round".

My 511 will also go sideways, a few thousands. I don't try to get more than that. Keep the wheel clean, and if possible sharpen a clean chain. It is the dirt that causes the excessive heat.

I like to go around the chain twice on each side, maybe more if really rocked bad. I have almost convinced the local "master" of the file that the machine can do a decent job, and is way easier.

-Pat

 

[Ductape]

engeneeringnerd,
i use exactly the same method with my Northern Tool grinder. There is just a little play, enough to move the grinder a few thousanths. I too have found using it this way doesn't blue the teeth. Have you put an old stone on your grinder to play with raker depth yet?

 

[Engineeringnerd]

I have a number of stones, but doing rakers is a bit of a pain. I'm ashamed to say that I often just grind the rakers on the side of the wheel by sight and feel. The depth isn't quite as precise, but I'm able to round the leading edge and make the chain run smoother. Using the grinder usually takes several passes per gauge unless you very carefully center the raker with the wheel. I guess I could loosen the rail and just slide the chain under the wheel (my rail closes automatically when you lower the head), but this would be tedious as well.

I've thought of buying one of the $39 Northern Tool grinders for depth gauge filing, but I don't really have the room or do enough chains.

 

[Haywire Haywood]

Feedback?

This is how I do it also. I never mentioned it b/c I figured I was cheating somehow and didn't want this brought to my attention. I set it to take off just a hair, and if a particular tooth needs a little more, I flex the arm into the tooth a little.

As for rakers, since I don't have any 404 chain, I dressed the 404 wheel that came with my NT grinder flat and use that. I manually file one down with an Oregon raker gauge and then adjust the wheel so it just barely touches it. I then grind all the other rakers to match and round off the front of the raker with a file so there's no square corner to drag in the cut.

Ian

 

[hokiebob1]

I do the rakers using my Northern grinder with the 1/4" wheel, but rather than setting it at 90 deg, I set it at 75 or 80 deg--this gets the correct height and also angles the leading edge down - it works quite nicely. You can play with the angle, but the intent is to set the raker to the correct height and also angle it in one process.

 

[Engineeringnerd]

hmmm, so an angled raker from front to back works for you? I have a 1/4" wheel, which I have used at 90 degrees. Never tried it at an angle.