Taking depth gauges down past spec.

[njc110381]

Hey guys. This may seem like a stupid question but I'm not sure about it and it wasn't covered in any detail when I did my training, so I figured it's better to ask than wade in uneducated.

 

Every time I sharpen my saws I use the Stihl depth gauge tool and take the rakers down too. But it seems that once I touch the chain it doesn't cut like it did when it was new. I can get a good edge on the chain and all the teeth are the same length, but it just seems like I'm not taking enough off of the gauges? Anyway, I used a saw sharpened by someone else the other day and it cut so much better. He was saying that he takes the gauges down a bit past where the guide tool allows.

 

Is this a good plan? I understand the more the chain digs in the more likely it is to bite and kick back but I didn't have any negative feeling with my mates saw. There was an obvious difference in the feedback I was getting from it but it wasn't violent, it just cut better! I'd like to do the same to mine but thought I'd ask opinions first. Does anyone else here do it? I know some makers have different specs for hard and soft wood, so there must be some room for adjustment. I just don't know how much!

[Rob D]

Big J will love this thread if he catches it!

 

 

It's all a bit of a piece of string questions as depth guage reduction and how you tweak it depends on what wood your cutting, saw choice, bar length, chain type, have you ramped or just flattened them etc etc...

 

... so one persons experience may not match anothers even though they have said they have tried the same thing.... so you really need to learn it yourself...

 

 

If you're really interested then go here:

 

http://www.arboristsite.com/community/threads/raker-depths.264395/ as over the pond they are a long way ahead of us....

 

 

It's the angle of between the working corner of the chain and the top of the depth guage that you need to maintain ie. so as the tooth gets smaller you need to reduce the depth guage more than .025" to maintain the angle....

 

 

BobL on there knows his stuff - the cutter rocks its way into the wood - a reason why chain tension is more important than you think in the way a chain will cut:

 

It doesn't matter whether it's cross or end grain cutting a CS cutter does not work like a wood plane. The cutter rocks its way into the wood as determined by the cutter angle and chain tension. The raker and a constant cutter depth is maintained during the life of the chain the amount of "rock" available to the cutter decreases and it just cannot bite enough wood no matter how sharp the cutter is.

 

 

It's a combination of factors with how a chain cuts - if the saw does not feel like a live thing in your hands then the chain can be improved! I struggle with getting it right by eye and have to use a guide to get a chain spot on...

 

 

[wyk]

Factor chain is set up to be as smooth and efficient for as many variables as possible. A chain set up for one job may not do another terribly well. Here is my 044 set up with a chain that I use for conifers and Rhododendron. Low rakers and less acute angle so it lasts longer cutting dirty wood. It becomes grabby in Beech:

 

https://www.youtube.com/watch?v=K-uMkEhRNAE

Edited November 29, 2014 by wyk

[Gerbutt]

That sounds and looks like a right beast!!!

[Big J]

Big J will love this thread if he catches it!

 

You know me well Mr Dyer!

 

Chains come out of the factory at a general purpose and excessively safety orientated setting. Even on smaller saws, you could afford to take the depth gauges down. When I was doing more cutting, the first thing I'd do with a new chain is sharpen it and take a lot off the depth gauges (that was a 550xp on a 13 or 15" bar cutting hardwood). Factory spec chains are slow.

 

Now at the other end of the scale and the double ended mill, you have to take so much off the depth gauges (to make use of the 17.4hp on tap) that an angle grinder is required.

 

The long and short of it is that you will find a set up that works for you. If lower depth gauges is preferred, go with that.

[agg221]

Whilst I agree with what has been said, one thing to add:

 

But it seems that once I touch the chain it doesn't cut like it did when it was new.

 

The chain out of the box is general purpose. Your original question suggests that you start getting this problem as soon as you sharpen the chain, even from the first go? If this is the case, the chain certainly shouldn't get worse than it was out of the box after sharpening, even if you don't touch the depth gauges.

 

If this is the case, it suggests that at least some of the issue may be with your general technique? One way to check - next time you are seeing your mate, take a chain you have just sharpened and are not happy with, and ask him to sharpen the teeth but not touch the rakers. If it cuts better, you know it's not the rakers; if it doesn't, it is.

 

Alec

[miker]

taking the rakers down too much will make it grabby and you will constantly bog the saw down, not enough and you wont cut anything, its a fine line between the two, get a depth gauge for rakers to keep a happy medium between tooth and raker height

[Mull]

Been struggling with rakers for last few weeks, this thread has helped me out loads!!👍

[Macpherson]

Hi, it seems to me that assuming that you`ve tuned the saw engine to run at it`s optimum and you can rely on it to perform the same each time that you use it, then it becomes a good test bed for experimenting with the sharp end, after all, a drill for example, needs different angles and cutting speeds for different materials, so a chain is the same. If your chain is real sharp, at your chosen angle, then if you take the depth gauges down in small increments, till it starts to bog down, you`ll soon get a feel for just how much you can expect of the saw. It`s called tuning, but nothing to do with the carb !!

[Logan]

Very good posts from all, I can only add to Alec's spot on post that on stihl RS 3/8" chain, on a 60cc 362, new chain can be grabby for bore cuts when new out of box, when checked with gauge the rakers were lower than 0.65mm new and before touching with file. One pass with file on cutters made that chain about right in ash and birch. But they were still a touch below gauge.

 

So njc, you could also check a new chain on the bar with your gauge and see where they sit when it's running good.

Filing definitely changes shape from original factory grind, so I agree that best way is to develop your own process until "your" tuning produces a working chain, and then adapt chain for cutting different woods if you're in different species for long periods.

 

Cheers, John.

Edited November 30, 2014 by Logan
illiterate mess