Case hardening of cutters?

[Dave Shepard]

Yesterday I tried to sharpen a chain that had been sharpened at the saw shop on a grinder. With a brand new file I was unable to properly sharpen the cutter, and with a new flat file I couldn't take down the rakers unless I came at them from a 45 degree angle. Once I got the top taken off, I could then file as per usual. This is a chain that I had hand filed a few time before no problem, but got sharpened when it was in the shop for other repairs. I think the grinding is case hardening the cutters and rakers. They take the rakers down on a bench grinder. Is this an accurate concept? This is a work saw, and one of the reasons I usually provide my own saws. Chain is marked "husq".

 

[SkwerI]

Yup, you got it right.

 

[Dave Shepard]

Well, that sucks.

I've been using some of the work saws this spring, as well as borrowing a 372 and 385. I've been taking the bars off and using my own b and c, as I know what I'm working with. My boss offered to buy a big saw when my 394 blew up, but I figured that was pointless, as I would not have control of it and it would be dull or not where it was supposed to be when needed and that would just piss me off. I'll be sure to keep my chains away from the grinder. I've always hand filed anyway.

 

[sawinredneck]

Yup. seen it before! The guy sharpening the chain doesn't give a rip, just set it up so it hit all the cutters, no matter how hard it hit them! Leaves a nice blue or sometimes black, on the edge of the cutter. Makes the chain useless IMO!

 

[NeTree]

I agree; and I think hand-filing does a better job most of the time, anyways.

 

[flushcut]

That's why nobody sharpens my chains but me.

 

[NeTree]

 

[Al Smith]

Lawdy they get like 7 bucks a pop to grind chains around here .In addition to hardening the cutters they take so much off you'd be lucky to get more than 5 sharpenings out of a chain .I'll take my file any day .

 

[Cobleskill]

Moroons that don't know anything about metal, or don't care.

 

[brendonv]

"Hey kid, go sharpen this!"

 

[Al Smith]

While I'm thinking about it Baileys sells a file ,Arbor-Pro I think which is a less agressive type and it works well for hard chain ,like Stihl branded .I would assume it would work for burned cutters also .

I can't remember the number on it but a little search on Baileys site should lead to it .

 

[Cut4fun]

Yep done it myself when learning to use my grinder on rocked out chains. Take to much off in single pass to get all cutters the same. Saves time but ruins chains like you mentioned above.
Learned to take as little as possible on several passes on rocked chains to keep from over heating the cutters.

 

[Al Smith]

Every so often I have to "Dremel " a rocked cutter .Not the best practice but it works .

 

[cory]

Sometimes if I cut into metal etc, some of the teeth seem to get hardened and hard to file until you manage to file through the hardness to get back to softer, more filable metal... is this like instant case hardening?

 

[Dave Shepard]

In this instance, I think you might be fighting some chrome that has been bent over. Once you've filed that back into shape, it's usually good going again. Stihl chain seems to be much worse for this than Oregon in my experience.

 

[Al Smith]

Speaking of metal ,I did just that yesterday .Nicked a freakin chain link fence with one of the 200's and had to put the thing in the vise to save it using an Arbor- pro file .

It does just exactly as described, bends the chrome over .

 

[wiley_p]

like anything, if it isn't done right stuff gets screwed up. I've been grinding my chain for over 20 years. Super sharp, perfect corners. Most folks who are under the illusion that they can file chisel, dream about chain that a Silvey can turn out.

 

[Peter]

I've been grinding my chain for over 20 years.

Bloody hell it only takes me about 15 minutes to do it by hand.

 

[HolmenTree]

That metal you find in the cutter's gullet after you cut a nail etc is just that ..... a piece of the nail. If you're getting chrome in there then you're putting way too much hook in your side plates, just my opinion.
Try using a 4 1/2" angle grinder to bring back those rocked out edges, the coarse disc is quick and doesn't put the heat on the cutter like a fine stone Dremil does. With the chainsaw in the bench vise and the chainbrake on touch the cutters with the angle grinder in intermittent strokes so as to not burn or heat up the cutters. Then finish off with a hand file. Works real slick.
I believe everyone should learn to touchup a chain in the field with a file. Whether its chisel bit or round ground.

 

[Dave Shepard]

What I'm seeing on a rocked chain is the point of the cutter being bashed downward. This can be hard to file at first until you have reshaped the cutter.

 

[Cut4fun]

I used grinder the other day on a 3/8lp chain used to cut up a couch.

 

[Al Smith]

It's just a fact that if you run a saw long enough you will hit metal, rock or the dirt sometime .

 

[Jed]

Peter: Good one man!

Dave S., Cory, Al and Williard: If you guys hit a nail, and there's pretty big damage, or if a new guy sticks it in the dirt or rocks it hard; try using--with the bar in a bench vise, or at least, a well-seated stump vise--a regular mill bastard, held vertically (not horizontally) to restore a factory-like angle to the cutter. If you get the saw really secure w/ the bar in a bench vise, you can just reef on that son of a gun, and all that hardened metal will peal off in about three strokes. This saves your round or double-bevel files, and it cuts WAY quicker. Then the round or double-b will eat through the gullet like butter.

 

[cory]

Good ideas here.

A question: the chrome mentioned that can get wacked/ rounded over into the gullet- does that mean only the top plate is chromed, not the whole tooth? I should already know this....

 

[HolmenTree]

The upper top end of the cutter's side plate has a layer of chrome continuing into the top plates layer which makes a strong "working corner".

With a rocked out or rounded over cutting edge its not so much the chrome making it hard to file the cutting edge back to shape, its the large mass of bent up metal that needs to be filed away.
In this situation what helps ease the filing difficulty is first have a brand new file at the start and file the damaged corner off at 0 degrees angle [less length of cutting edge to file] then after the rounded corner is gone then file in your 30-35 degree angle.