To square or not to square

[bonesaw]

Hello everyone! I've  been  a lurker for a few months now and have finally built up the courage to register.

I have an ms661c which I love to bits. I've put a 42 inch bar on it made by GS forestry. My main use is to make slabs out of fallen timber at our property and there's plenty to go around so far. I'd needed a skip tooth chain and my dealer only had a square cut Stihl 36 RSLF which I have been using so far.

I've been trying to figure out how to sharpen it and have finally discovered that I'd need a pretty expensive grinder if I really need to keep the square cut. I tried hand filing with a triangular file that stihl sell but it just didn't do the job properly. So the question that I really wanted to ask was, is it ok to go to a regular circular cut?

I do have a half decent grinder, but I'm not sure what thickness wheel would be best suited to achieve this.

Sorry if this post seems amateurish. I'm just starting my chainsaw journey.

[doc henderson]

RS uses a round fie or grinder.  you can use a file or a disc on a grinder.  a 3/8th or a 0.404 uses the same diam. file or thickness of disc.

[lxskllr]

You can convert square ground to round, and then back again if you chose to. Square filing, and/or using a grinder would be a hassle milling. Doing oak, I had to sharpen about every 15', though I pushed it to 22' just to finish the cut. It would take a case of chains to do a milling job if I didn't want to sharpen in the field.

[bonesaw]

Thank you for the advice!

I've been doing mostly pine so far and its good for a couple of slabs. I give it a quick hand sharpen eveytime I fill up which is quite a bit when slabbing. The other kind is Redgum though, very hard and dense. Need a really sharp chain to cut it.

Guess I'll just convert to round as it just makes it easier. The chains have gone up in price recently from 180aud for a 25 foot box to 240 now!

[charles mann]

Iv used factory cut square for csming but since i dont know how to square file, i convert to round. I see no difference in sq vs. round in quality of cut, except that the sq dulls faster esp in hardwood. 
Have you tried madsens to get rolls of chain? I know you said price is in aud, so assuming you are down under, shipping and the currency conversion, but you might be able to buy per 100' roll cheaper in the end and possibly in the profile you want. 

[hedgerow]

bone saw Welcome to the forum. Seems like in the US the western part does a lot of square grind chain. About ten years ago I was on a trip out west and stopped at Madsen's saw shop. Talked to them a lot about square grind as I was thinking about buying a grinder and changing over. I bought a few square grind chains and just didn't like them for the wood I cut which is a lot of locust and hedge. I just converted those chains back to round. Its tough to file square grind chain. 

[Old Greenhorn]

Well, this is like the "what oil mix do you use and how much?" conversation. It comes up a little less often though. There are plenty of discussions on this in the forums and everybody has an opinion they are pretty firm on. 
 Firstly, if you are CSMing, why wouldn't you use ripping chain rather than standard square or round grind? 
 As for square sharpening, I have my (firm) opinion also. That is that I have seen no evidence that the chain gets dull faster then round. I have no trouble filing square chain and in fact can do it faster than round. It IS dang hard to learn, especially in the absence of someone who can teach you hands on, but once you learn it, it's pretty simple, provided you get the tooth geometry correct. You don't need a grinder to do square chain. But to file, you do have to work on the skill quite a bit before you get good, and I say again, learning is not easy without a guru. I tried on my own for weeks with poor results. Then I found a guru and he set me straight in 5 minutes. Madsen's has a good set of instructions in the back of their catalog, worth looking into.
 I have converted from round to square (LPX chain) and back again. The filing in the conversion takes a bit of time, after that, it's simple. I like the profile and it cuts like mad. I use a 6 corner file which can also do the rakers.
 These days I use X-cut on all my saws and am quite happy with that.
 No matter what you do, YMMV.  Good Luck.

[charles mann]

@Old Greenhorn
What grind is on a ripping chain if its not a square or round? Iv ordered both square and round grind ripping chain. Is there a special grind for them, not just the 10° profile? 
When i ordered my chains from madsens, they asked the type of wood i would be primarily cutting (felling and csming) and even they recommended round for hardwoods and or dirty wood bc the sq grind doesnt hold up as well. 
Now, your experiences will differ just like anyone else's and not one experience is any more right, wrong, good or bad. If i could learn to sq file, id like to give that grind a better chance than just 1 pass through a log, then reprofile the grind to a round now that im felling more pine than hardwood. But with the logging industry in my area what it is, which is none and no one in my area or the area in east tx where i do cut, to show me the correct or as correct as the human hand can be, how to file a sq grind, i will error on the recommendations from other pnw timber fellers and madsens, that dont have a financial dog in the fight, other than just making a sale no matter what. 
If sq works, keep on keeping on, if round works, keep on keeping on, just find a grind and ° profile that works for each user, bc one is no more right or wrong than the other, its just personal preference.

[Old Greenhorn]

Yeah, sorry Charles, just a mis-communication there. The OP mentioned square and round and never mentioned ripping chain in either. So I was trying to find out if he was using rip chain or not. Nothing special beyond what you are aware of. Yeah, I know Madsen's takes the company line on the square "dulling easy", but they are just parroting what's in their literature, which traces back to when there was an industry drive, lead by Oregon, to phase out the square chain completely. There really is no merit to it and it was just marketing guys that came up with it. However, because it made it into print, it is still persistent all over. I call it an unfounded rumor. ;D I ran square for a year and kept an eye on that trying to prove it one way or the other for myself and saw no evidence of that EXCEPT that square has an acute corner on it which does not last very long before your eye can detect a reflection telling you the corner dulled. However, the cutting ability of the chain is not reduced for quite a while after that corner gets the shine on it. I watch my chips and listen to and feel the saw to determine dullness, and I saw nothing different than round. No chain likes dirty wood regardless of tooth form.

 I really had a hard time learning to square file. I tried and tried and read everything. But there are some things you just can't learn from published info. I finally found a guy who could put it in simple terms an old cutter grinder could understand and it worked for me. The key is that the inside square corner in the tooth MUST come out at the same point that the top plate and the side plate on the tooth meet. If you can hit that, you've got it made. Once I learned that, life got really good.

[ehp]

Square is faster and smoother than round , it is harder to file but its not that hard to do , down here I donot square cause first so much dirt in the wood from the wind blowing it off the sand fields and next is the amount of fence or steel in the trees is lots in some bushes  but up north I square filed for years for falling timber and race chains

[barbender]

Why don't mechanical harvesters run square ground chisel chain instead of the semi-chisel that they use?

[lxskllr]

I *always* see terminology errors when this discussion comes up. There's two aspects to the discussion. Semi chisel vs full chisel, and round ground vs square ground.

 One can round grind a full chisel chain. That's the "normal" way of sharpening. I don't believe a semi chisel chain can be square ground. If you could even get something to work, it would defeat the purpose of semichisel.

So... When you're talking about "square grinding" it means you have a weird looking file in your hand, and you're definitely using full chisel chain. If you're "round grinding" you have the standard round file, but nothing can be inferred about the chain. It could literally be anything aside from archaic chain styles. It could be chipper, semi chisel, or full chisel.

[ehp]

You cannot square file a semi chisel chain and make it work, you need the corner of the tooth to base the square off. Next the machine has alot more power to drive the chain than a saw . A square ground chain on a harvester would be pretty fast . If it is setup with .080 gauge in .404  you could square a chisel chain . It would be fast but lots of work and you would not want to touch the ground with it . Thing with square is it does not feel as fast cause it cuts smooth when filed correct but time it on a camera and you see its a fair bit faster . The easiest way to learn is just do it , file a tooth and then study it and look at under the top plate so under the tooth and see where your line on the tooth are and then see what happens when you change your angle of the file to what happens to your tooth . Biggest thing is make sure you hit the top corner correct , to low on the corner and you end up with a peek which will dull pretty fast , If your to high on the corner you dull corner where is will not bite into the wood

[barbender]

 The point I was trying to make is that there is a difference in edge durability in the different tooth and grinding methods.

[ehp]

I'm not sure you would really need square on a machine . Would be harder for lots to sharpen in the field but could be done .  On 3/4 inch I do not know of any chisel chain made but somebody could of made it .  I ran the chain serts chain on the firewood processor I had for a while but switched it to .404 and was alot happier with that . Lot faster and less than half of the sawdust 

[barbender]

 Maybe there's no difference in longevity between round ground chisel and square ground. I have no idea as I've never ran a square ground in my life, or even seen it in person. There is definitely a difference in edge holding between full chisel and semi-chisel though, in my own experience.

 I don't mean to be vague, I was trying to address OGH's assertion that square ground dulling faster was propaganda put out by Oregon. I've seen a difference in all if the other tooth styles I've had experience with, I don't have a hard time seeing how a square ground may have less durability but like I say, zero experience with it.

[barbender]

 So could I try square grinding a round ground chisel chain, with the correct file? Or do you need to start with a square ground?

[Old Greenhorn]

Yes, barbender you can. It needs to be full chisel, not semi and the top plate and side plate should meet at a 90° angle. I made my .325 square from LPX chain. Can't buy square around here and I don't think they even make it for .325. My first attempts crashed and burned until I learned that key point mentioned above. 
 It does take a LOT of filing to get the square shape from round. For sure I would never consider 'switching back and forth'. If you want to try it, start with an older chain, convert it and stick with it. If you don't like it just get another chain and go back to whatever is your next flavor would be my advice.

[bonesaw]

Wow! Thank you everyone for this wealth  of knowledge!

The square grind just happened accidentally as that was the only skip tooth chain that my dealer had. I have the admit the cuts are super smooth and really good when milling as finishing the piece is easier. But I did feel that the chain does dull faster.

The problem was that very few people had seen this kind of grind in the wild. Even my dealer suggested that I use the round file to sharpen it which confused me as that will definitely change the geometry of the tooth.

I am terrible at sharpening the square grind though. I managed to get a triangular file that Stihl sells presumably for a square grind but I did it so bad that the saw started pulling towards one side. I'm decently good at sharpening with a regular round file though.

So much to learn!!

[barbender]

OGH, most Oregon round chisel specifies a 10° horizontal angle on the top plate. I don't know if the top plate is actually angled, but if it does have the 10° angle the top and side plates would not be square to each other. Therefore not a candidate for square grinding, correct?

[Al_Smith]

Regular round filed chisel chain rips a lot faster than so called rip chain .You just use a different angle of attack so it doesn't jam up with noodles .Besides that if it's to be finished lumber it will be planed .   

[Old Greenhorn]

BB, that refers to the angle of the file, not the top plate. I there is a largish radius on the OUTSIDE between the top and side plates that would be your no-go signal.

[bonesaw]

So I got a bit of a chance to experiment the last couple of days. I had the original chain the saw came with, gave it a bit of a sharpen. And then i used my originally square and now round 10 degree skip tooth and the difference was still night and day!

The skip tooth was noticeably a much smoother finish. And it felt like it was cutting faster.

The other thing was that it felt like the saw went faster if I backed off the throttle just a bit, it seems to cut faster. Maybe I'm imagining it?