Chainsaw Repair
Chain - Grinders - Filing - Wood Milling - Tools - Welding - Machinist - Mowers - Tillers => Chain - Bars - Grinders - Filing => Topic started by: John Mc on April 18, 2013, 09:49:43 am
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Several years ago, I ran into a problem with some Total chain (made by Carlton, I believe) where a couple of the teeth on a loop were so hard I couldn't do much with a hand file. The rest of the teeth filed normally. I had a similar problem with a couple of depth gauges that would ruin my flat files. I chalked it up to bad heat treating of the chain, and when it happened again, I stopped buying the Total/Carlton brand chain. (It was only a couple teeth each on two loops of chain, out of maybe a dozen chains, but it was a pain in the neck.)
I didn't think much more about it until it happened with an Oregon chain recently. There are a couple of teeth on the loop that the file just slides past, without doing much. Switching to a brand new Pferd file makes no difference. It's very noticeable, since the rest of the teeth on the chain sharpen so easily. What was odd was that this chain was already filed halfway back to the witness marks. It had been a while since I used this chain (still mounted on the saw from the last time I used it), but I'm sure I would have noticed when I last used it.
I have a theory on this: I almost always hand-sharpen my chains, but occasionally if they get rocked, I'll take them to a shop with a very good reputation in my area and have they owner sharpen them for me on his grinder. This last Oregon chain had been sharpened at the shop. I'm wondering if he might have hardened the tooth by getting it too hot with the grinder. (It's been too long ago for me to remember whether the Total chain was grinder sharpened.)
I worked for a good bit of my life for a company that makes and heat treats high carbon steel wire, and some chrome alloys. All of the steel alloys with which we work need to be heated, then quenched to harden them (we then heat the wire back up to "temper" it, otherwise it's too hard and brittle to do much of anything with it.) This shop does not quench the chain, or do anything to cool it other than let it sit. Ordinarily, I would expect heating the steel and letting it cool in air to soften it (annealing the steel). However, I do know there are such things as "air hardening" steel alloys that basically quench in air (and small parts such as a chain tooth will tend to cool rather quickly anyway). You'd have to get the metal a good bit hotter than the minimum needed for annealing to have even a chance at hardening it, but I suppose it's possible to get that contact point with the grinding wheel hot enough. Does anyone know what type of steel these chains are made of? If I knew that, I could figure out if "air hardening" after grinding is a possibility.
The guy at the shop is very experienced. Has been in the business for decades. He's one of the ones the pro's in the area bring their saws to when they need repairs. He is getting older, though (he's well past "normal" retirement age), and I suppose it's possible he occasionally hits a tooth too hard, overheating it.
Have any of you guys run across a hard tooth in the middle of an otherwise normal loop?
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I have only seen this on a hardened tooth that has been over heated on a grinder. Never by hand or factory that way.
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I'm thinking that this was form a grinder. This most recent chain was grinder sharpened before I put it away last time I used it. The previous Total/Carlton Chain was so long ago, I don't remember.
I'm so used to dealing with steel that requires a water or oil quench to harden, that it never crossed my mind that this could have been "air hardened" until now. I just assumed that over heating during grinding would have softened it (softening is still possible if it's not overheated beyond a certain critical temperature).
I'm still curious what the alloy is in a chain... but not curious enough to pay to send a piece out for chemical analysis...
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If you worked in a metal heat treating plant, they should have several people that can grind a stream of sparks from a tooth and tell you exactly what metal alloy it is.
I used to work in a steel mill and metal identification was a critical factor as we worked mostly with alloyed steels. I would take parts from the machine shop down there for alloy I.D.
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I've seen plenty of folks who can get get pretty close guessing the carbon content of the steel (I used to be half decent at that myself, but far from an expert, and I've been away from it for long enough that I wouldn't even hazard a guess now). I've seen a few who can make a decent stab at some of the other alloying elements.
I've never met anyone who could get the actual grade of steel with any real reliability (i.e. that's a 1050 grade, or that's 4140 grade, 9254 etc.) If you've got access to folks who can do that you're lucky. It seems to be a vanishing art. With all the liability concerns around these days, we always have to do an analysis if there is any doubt, or if a customer comes in with a question or claim.
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I can get pretty close to the classification by the chips a lathe makes but certainly not to the true alloy .
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When I would get one sparked, he would spark it against know samples.
One thing about it, I know D2 tool steel at a glance.
I also know AMPCO Bronze when I see it and when I try to drill or torch steel, I know of it is manganese plate.
Armor plate is a new one for me. It came along after I left.
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I'm real close to AMPCO 18 as I have a sliver buried in my thumb .
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at what point does the hardness have to be where that piece of metal is so small that you almost can't see it, hurts like you just lopped off the tip of your finger and jammed it into a salt shaker >:(
i did tires for almost 5 years at the local popular tire shop and can tell you from accute experience that the little steel belts hurt worse than a nail or piece of glass much larger in size.
hell. it didn't hurt near as much when i nearly cut my left thimb off.
well. the needle in the cut for the freezing hurt like hell. but again. it's a little tiny steel needle :-[
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I had some Carlton chains here that I sold them come back hard as glass.
I found they had run hot.
It is likly just surface. If it is one or two teeth it is easy to do by hand, but if it is a hole chain I grind it first, then file.
To get this harder surface of it is not easy, but a stroke with another filr might crack it enough to get correct cutting again.
Vibration doing this kills/dulls files so try to make sure file doesn't vibrate, instead cut as it should.
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This chain had 3 or 4 teeth hardened. I tried multiple times with the file I had been using with no luck. Pulled out a brand new Pferd file, still no luck. Both files subsequently did OK on another tooth in the same chain.
I know a grinder would probably do it, but I don't fancy bringing it back in for that, since that's probably what caused the problem in the first place.
John Mc
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hit those teeth with the dremmel a bit to get rid of the surface.
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hit those teeth with the dremmel a bit to get rid of the surface.
Now WHY didn't I think of that? I forgot I even owned one. It might even be worth picking up the appropriate sized bit for the dremel...
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Whatever that brand of files that Baileys sells has a finely toothed surface which I have found works better for me on hard chain like Stihl .It's not as agressive as say Pferd files .
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I had been using Oregon files. Just started the box of Pferd files a month or so ago. I thought I'd also try some of the Save Edge files next time around.
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I have the first Carlton chain that I bought in 20 years on my workbench that I bought from Bailey's last fall, and it has one cutter that is as hard as heck right out of the box.
Good luck removing the case hardened surface with a dremil, will only keep the cutter hard. Good idea if you want to remove foreign hard metal stuck in the gullet.
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It's probabley not just case hardened .I'd imagine the whole cutter is hard .Well I suppose in some freak way just one cutter might have over heated while it was being ground and cased it a tad .
If they factory grind it like I assume it's done with coolant .Periodically the wheel needs dressed for two reasons .They get out of shape or they get loaded up .A loaded grinder wheel coolant or not will really drive heat into the steel .It's a form of tool steel and can it ever get hard .
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It's possible for a 'hard' link to come from the factory if they screw up in the heat treating process. But most of the time they are the result of overheating or 'blueing' on the grinder.
Good news is that the cutters will still cut, and you can grind past this to make the cutters 'file-able' again.
Philbert
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A couple of years back I bought some loops of Sabre '880' 3/8 chain for a Homelite I was running. I was intrigued by the shape of the cutter because it isnt quite semi chisel nor is it full chisel. It has an odd groove running down the side of the cutter. Even though its new chain, its very hard and difficult to sharpen. Thinking it was the chrome plating, I used it when in dirty wood. The aggressive Save Edge files wont clean it up unless you push it. If I can get a couple pics to come out, I will post them up.
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Lesson learned..Carleton is crap and always has been,QA is not there strong suit.
Stihl is tough to file also but a good tooth. Oregon is the only chain worth a darn as far as I'm concerned. Stihl is better but hard to file and is hard on files.
Lately Woodsman pro has a 73LGx tooth, which is the best, on a Carleton chassis, which is fine, already narrow if you want to race, for like 14 bucks or whatever a 20inch loop.
Ask before you buy though.
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I tried the Woodsman pro when Baileys first started selling it .It did fine until I tried to file a compound angle like Oregon 72 then it got bad .Now dang it I can file a chain as good as anybody .Made me mad and I quit using it until good ole "Crofter" Frank ,TW's Dad showed me the error of my ways .That praticular one or at least so at the time only took a 90 degree straight accoss not a 10 compound because of the way the top plate met the side plate .I learned something I didn't know .
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I remember you pointing that out to me some time ago, Al. It made a huge difference - larger than I would have thought. I've since stopped buying the Woodsman Pro -- not because I didn't like it, but because I kept forgetting to check what kind of chain I had on when sharpening in the woods, and would end up sharpening my Woodland Pro chain with the 10 degree compound angle.
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I think in this case its not a 10 degree down angle thing it's the fact you take the sharpest file there is, use all of your strength, and the file just scrapes over the tooth removing zero metal. It's harder then the file.
Then the next tooth you remove an 1/8th" in two strokes because its so soft.
I would two of each teeth per loop....That's when it was 11.99 at Baileys in 2003 ish.
Even Baileys realised they had a problem,kept the chassis probably because it was cheaper and purchased decent teeth.
I'm just guessing, but something positive changed because Baileys chain is pretty good. I was told by someone at that company about the Oregon teeth.
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I got some chains in trade and I swore some looked like oregon cutters on a carlton or WP chassis. Guess I'll snap a pic next time thinking about it. Then again I could be FOS and my mind dont remember what I saw.
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it has no witness mark but is a 73/72 lgx ;) a file will tell you exactly what you have
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That stuff I got wasn't praticularly hard as I recall .They are hanging on a nail some place in my garage I'd imagine .I've got so many loops of chain and use them so little here that last several years I'd be a hundred before I'd ever needed to buy any more .
I'll bet I've got over 20 loops of Stihl chain I never paid a dime for .Wrecked chain a trimmer gave to me which I repaired or cut down for smaller loops .What the hey cheap is good free is better . ;)