New vs sharpened chains.

[defensiblespace]

I have been taking my chains to a company to have them professionally sharpened. I have noticed that the resharpened chains do not stay sharp for as long as a new chain. After closely examining the sharpened vs new chain, I noticed that the cut was different. The new chains have more of a square cut and the resharpened chains are round. Is there a type of chain sharpener out there that will resharpen with the square cut? I am in the market to buy a sharpener this year. We do a lot of cutting of thick, dense brush at ground level, so as you can imagine, we need to sharpen quite often. Probably at least three chains a day. Something that I can hook up to my truck and run off a power inverter for mid day sharpens would be awesome. I have been using a dremel tool, but would like to step up to something a lot more precise.

 

[avalancher]

Learn to sharpen with a file, you will save a boatload on trips to your local shop,get a better sharpening(at least after you learn to use a file)and your chains will last a whole lot longer.
If you do a search on the boards here, you will pick up a lot of tips on sharpening by hand,Stihl also has a guide on their website to help you along.
You can also pick up a handy file guide made by Pferd,you can find it at baileys among other places.It will help you keep your angles correct.
No way I would let any shop sharpen my chains,they take off way too much metal.Plus, you can sharpen in the field,no need to switch out a chain just because its dull.Grinders have their place,but save it for a rocked out chain.

 

[BlackCatBone]

I think Avalancher makes plenty of sense here. Filing by hand is not hard after just a little practice, and it does not take very long either for routine touching up.

However for a rocked out chain, a grinder is much better than filing yourself to death. There are lots of grinders available, check Bailey's for a good selection. You can spend anywhere from $50 to $2500+ on a machine. The cheaper ones are good for taking metal off of a rocked out chain, where the nicer machines will rival about any hand filing job and are quicker too.

 

[defensiblespace]

I have been sharpening by hand for years, but found it to be time consuming and never as good as a machine sharpened chain. I have used a file guide as well, but actually found that I could do a better job without the guide. Perhaps there is a better guide that I should be using.

 

[woodbooga]

Sounds like rocking out might occur pretty often for the OP'er if he's doing a lot of cutting at ground level.

I hand sharpen, but my use pales in comparison as a firewood guy bucking up tree tops. I'd be searching about for an alternative method if I was dulling three chains a day.

 

[kruege84]

The only way to get better and faster at filing is practice, practice, and more practice. Just don't tell that to Allen Iverson... If done properly, it is possible to hand file a chain that will out cut brand new chain with the factory grind.

You said the new chains look more square. Could you be more specific? Are you talking about the actual grind of the cutter, or is the top plate coming out rounded when you get chains back? I hope you aren't buying square ground chains for brush clearing. You should be using semi-chisel in those conditions. Your chains will stay sharp a lot longer.

 

[defensiblespace]

The problem with the cutting brush that we clear is that it is often so dense that it is hard to see if a rock is lurking in there. At the level we cut, the brush is often dirty and then try cutting something as dense as manzanita all day long. The miners called it iron wood for a reason. Although I try to be as careful as possible, the occasional rock is inevitable. I often hand sharpen at lunch time to tune up, but the chains could almost always use a fresh grind by day's end. As for the angle of the sharpen, I have noticed that the angle of the teeth is square were you would run the file to sharpen it. Obviously hand files are round, so you have to turn a square cut into a round one when you first sharpen them. The square cuts stay sharp much longer though and I would like to be able to keep this same angle.

 

[Crofter]

The factory Stihl grind and now also I see the Oregon is done with the corner of a grinding wheel (intersection of rounded face and flat side so that all of the side cutter is sharpened with the face of the wheel and all of the top plate is sharpened with the side of the wheel. From projecting the path of the wheel, I feel that it has to have been done before the pieces are assembled into a whole chain. It does have a bit of the characteristics of a square ground chain. You cannot duplicate it with a round file and perhaps not with a round grinder (maybe a bit with a CBN or Borazon wheel) but you will not be able to duplicate it handily on an assembled chain. Usually where a hand filed chain outcuts the original grind it is a combination of more hook and enlarging the gullet area for chip clearance. I wonder if the stop watch would confirm a lot of claims that handfiling can outcut the original Stihl factory grind. That would have been true of chains not so many years ago but I am sceptical now.

For clearing brush perhaps you dont want a real hooky chisel chain! I like the Oregon DP as it stays sharp longer and the ramped guard link helps beeing whipped by grabbed twigs.

 

[defensiblespace]

I like the looks of that Oregon DP. I going to give it a try.

 

[2dogs]

The only way to get better and faster at filing is practice, practice, and more practice. Just don't tell that to Allen Iverson... If done properly, it is possible to hand file a chain that will out cut brand new chain with the factory grind.

You said the new chains look more square. Could you be more specific? Are you talking about the actual grind of the cutter, or is the top plate coming out rounded when you get chains back? I hope you aren't buying square ground chains for brush clearing. You should be using semi-chisel in those conditions. Your chains will stay sharp a lot longer.

I have cut a fair amount of brush in my time and I agree manzanita can be hard. It is also the worst to try to stuff in a chipper. I would go with semi-chisel too. In fact I do when I am brushing, all the way up to a 28" bar. I have a Granberg dremel type tool with out the clamp mechanism. I used to sharpen on my tailgate from the chipper battery. I prefer hand filing.

 

[wigglesworth]

It might be a just my imagination, but seems that my filed chains stay sharper longer, cut faster and last longer than ground chains. My buddy gets his ground and mine outlast his 3 to 1. No way I would take them in to get ground now, but as mentioned, a rocked chain takes forever to file.

 

[TreeWinder]

One of the reasons why a machine grind does not last as long as hand depends on the machine operators; if they are in a hurry they will overheat the chrome on the cutters and the sharpness will not last long.

 

[Crofter]

Grinding chains certainly does have a fairly large opportunity to destroy its edge holding capabilities or make it full of hard spots so you cannot file it. That is up to the operator of the grinder, and whether he rushes the job or runs a glazed stone.

Consider the cutter to be a controlled heat treat item. Heated, quenched and annealed to have it in the proper balance of hardness and toughness; my guess somewhat similar in material and treatment of a coil or leaf spring, so a bit difficult to file and probably about 50 points of carbon (medium carbon steel)

The quench temperature would typically be from above 1100 Deg. F giving a Rockwell C of around 60, followed by annealing temperature of around 600 Deg. F. to leave a residual hardness of about 45 Rockwell C. by comparison a bearing would be about 65 and a nail about 20.

Any temperature increase given by grinding that raises the temperature above the 600 degree annealing temperature further anneals to a lower and softer condition. Example an anneal temp of 900 F reduces hardness to 31 RC If that temperature increase by the grinder takes portions of the cutter up much higher than 1000 deg F. (very dull red in daylight) the subsequent air cooling as the stone withdraws, amounts to a rehat and quench and can leave that small area almost file hard at around 58 deg. Rockwell C.

Depending on the volume of metal overheated in the tooth and what maximum temperatures were reached, portions of the tooth could, instead of the design hardness of 45 RC, be at anywhere from a file hard RC 58 to a dead soft RC 22. Typical tensile strength could be then be altered from over 200,000psi. down to near 100,000 psi.

Very thin brittle edges tend to shatter quickly back to a blunter ragged edge if viewed under magnification. Alternately edges that were made soft tend to fold over at the very edge and shed the flap and wear roundish to another inefficient edge. Simply put you can simultaneously soften metal in the cutter and yet random small areas can be left with hard spots, neither one of which is good. I will attach a picture of a cutter that probably failed from being over heated, granted it was ground to quite a thin profile and knots could have been an issue but shows a good reason to be very cautious of grinding on a chain if you want the best performance. That said I still think a keener edge can be had with a grinder than hand filed but you have to be a lot more cautious of heat than most people would ever dream of being an issue.

 

[BlackCatBone]

A good anecdote supporting Crofter's post:

I realllly rocked out a brand new rsc loop. I am using an oregon mini grinder which has about a 4" wheel. The grinder does a fairly ok job for what it is, but with the small wheel it does grind pretty hot unless you tap dance with it. This chain had to have a lot of the cutter taken off, and I basically hogged most of it off and then came back with lighter taps to put an edge on it. When I was done, the chain was sharp and cut well, but it doesn't hold an edge anywhere close to what an rsc usually does and it is likely to the small grinder and hogging off a lot of metal.

 

[defensiblespace]

Lots of good info here. When I buy my chains, the only thing they are asking me is if I want full comp or skip. Looks like I need to start specifying different chains for brushing. I saw a few mentions of a chain getting "rocked". Does this mean the chisel is bent? It also looks like hand filing might be easier on a chain that does not have that square cut that I mentioned. Thanks for all the posts.

 

[BlackCatBone]

Here is what you originally asked for:

https://www.baileysonline.com/itemdetail.asp?item=46012&catID=9755

I have not used one, but Granberg makes pretty good stuff usually.

A "rocked out" chain just means you hit a rock, yes usually the tip of the cutter gets bent downward or blunted.

 

[motoroilmccall]

Grinding chains certainly does have a fairly large opportunity to destroy its edge holding capabilities or make it full of hard spots so you cannot file it. That is up to the operator of the grinder, and whether he rushes the job or runs a glazed stone.

Consider the cutter to be a controlled heat treat item. Heated, quenched and annealed to have it in the proper balance of hardness and toughness; my guess somewhat similar in material and treatment of a coil or leaf spring, so a bit difficult to file and probably about 50 points of carbon (medium carbon steel)

The quench temperature would typically be from above 1100 Deg. F giving a Rockwell C of around 60, followed by annealing temperature of around 600 Deg. F. to leave a residual hardness of about 45 Rockwell C. by comparison a bearing would be about 65 and a nail about 20.

Any temperature increase given by grinding that raises the temperature above the 600 degree annealing temperature further anneals to a lower and softer condition. Example an anneal temp of 900 F reduces hardness to 31 RC If that temperature increase by the grinder takes portions of the cutter up much higher than 1000 deg F. (very dull red in daylight) the subsequent air cooling as the stone withdraws, amounts to a rehat and quench and can leave that small area almost file hard at around 58 deg. Rockwell C.

Depending on the volume of metal overheated in the tooth and what maximum temperatures were reached, portions of the tooth could, instead of the design hardness of 45 RC, be at anywhere from a file hard RC 58 to a dead soft RC 22. Typical tensile strength could be then be altered from over 200,000psi. down to near 100,000 psi.

Very thin brittle edges tend to shatter quickly back to a blunter ragged edge if viewed under magnification. Alternately edges that were made soft tend to fold over at the very edge and shed the flap and wear roundish to another inefficient edge. Simply put you can simultaneously soften metal in the cutter and yet random small areas can be left with hard spots, neither one of which is good. I will attach a picture of a cutter that probably failed from being over heated, granted it was ground to quite a thin profile and knots could have been an issue but shows a good reason to be very cautious of grinding on a chain if you want the best performance. That said I still think a keener edge can be had with a grinder than hand filed but you have to be a lot more cautious of heat than most people would ever dream of being an issue.

Pretty decent description... One thing I noticed looking at your cutter... Whoever sharpens your chain needs to learn one MAJOR thing. TAKE DOWN THE RAKER. I'm amazed that chain will still even cut.