How Concerned Are Chain Manufacturers?

[Gypo Logger]

Since I have been using square chain lately, I have been wondering why chainsaw chain manufacturers use 25 thou. as their standard raker height?
Case in point: wouldn't 3/8 chain on a 50-60 cc saw be better with 20 thou rakers, than a 325 chain with 25 thou. on the same saw? We might think this is 6 of one, 1/2 doz. of the other, but with the bigger pitch and higher raker, wouldnt the 3/8 be less suseptable to damage and be easier on everything?
If chain manufacturers are really concerned with safety, why dont they start their raker height at say 20 thou., leaving the lowering of them to the discretion of the saw operator?
Its been my finding that casual users pay little attention to raker height or simply file them off indescriminatly.
The only problem with my theory, is that we cant add to raker height, only file back the cutter to get the height we think best.
In my 20 years of round filing, I always used 25 thou. on every saw as standard issue, now I find this was wrong in most cases, and that 20 thou. is better when we have the saws to drive it.
John

 

[Gypo Logger]

Or even better,why doesnt all chain start at 0 raker height, with witness marks on the raker at 5 thou. increments?
I guess to answer my own question, it is because raker height varies with cutter length.
Are raker gauges available that allow 20 thou. raker reduction?
I am back to free hand reduction till I find one.
Am I talking to myself again? I tell myself jokes once in awhile, but I only laugh at some of them, cause I have heard them before.
John

 

[tony marks]

good question brother.hope some of the gurus will hazard an opinion.but not me cause i aint a guru. still like to hear answers.

 

[Crofter]

JOHN: I think it has to do with the sad but true fact that the casual user runs dull chain. To make dull chain cut at all takes a higher angle of attack ( lower raker). Also lower rakers feel like the chain is really cutting! I agree that 20 thou rakers is way faster on my 260 Stihl than 30 thou. The 30 thou setting pulls hard and makes you think it is really cutting, but the stopwatch tells the truth. I think because of these two things, the lesser raker clearance on new chains wouldn't sell.

Frank

 

[z4lunch]

rakers

Steve here...
I had a friend tell me last week that he sometimes runs rakers at 35 to 40 thou, on his ms440.....I said nothing.
Like Frank said. The only way to prove it to them is to put it on the stop watch.
Steve

 

[eyolf]

This dovetails nicely into some of the other chain discussions around this joint.

I bought a loop of that Oregon safety chain with the bent-over rakers. Dern stuff cut smooth, but slow. I didn't have any kind of guage that worked to set the rakers, although they seemed high...around .015 by feeler guage and straight edge. I took the chain to work and clamped it in a tooling vise, used a height guage with indicator on a surface plate, and learned that the stuff was set, factory, to .0138-.0157, which I thought was pretty good tolerance control, but not enough raker reduction. Taking the rakers down to the witness mark leaves about .030, but apparently because of the geometry of the chain, it seems to work OK with .030 raker.

This is 3/8", 24" bar on a 395XP...it is entirely possible that the 395 has enough extra power to drag that chain around while a smaller saw wouldn't, but it does seem to cut smoothly. I did mount this combo on a Jons 625, and noticed immediately the power diff, but it still cut fairly smoothly.

I've taken a lot of time to make my point, but the point is, really, how many people will really care? How many will take a little time to play with things and find out what works best? Probably only those of us that have been reading the Art martin thread and goading each other on to find out where to get an extra little bit...

 

[Chainsaw_Maniac]

Most people don't even own a gauge to measure raker height. They either don't file them at all, or file them by the number of file strokes per raker.

For those chainsaw owners that actually measure the raker height, and carfully file them........there's no "perfect" raker height. Depending on the size of the saw, the length of the bar, and the guys skill level at cutter sharpening the best raker height can be anywhere between 0.015-0.035. (I'm still experimenting myself).

Gypo's right about the best out of the ox chain for a skilled sharpener. But for the average joe who wants a chain that's ready to cut with on an average saw out of the box, I guess they must think 0.025 is best.

 

[Crofter]

Adjustable raker guage

My Stihl dealer showed me an adjustable raker guage, I believe 0 to 60 thou. in a catalogue. I asked him to order me one but don't know who makes it. Around 10 bucks. In the meantime I have made something similar to the one Art Martin showed a pic. of. No numbers on it so have to use a feeler guage to set it.
If you can get a piece of 5 thou brass shim stock you can epoxy it to the underside of your 25 thou fixed guage. The brass is a little easier on that hopefully razor sharp tooth point too.

Frank

 

[Crofter]

adjustable depth guage

I just got a call from my dealer and went and picked up the guage. It has Oregon Part # 010-400 on it and a tag on the bag says Theo Turgeon. Guage is stamped Made in CanadaIt goes from less than 20 to 32 thou and there is a dimple preventing further travel this direction. It is L shaped fitting down the side of the bar about 2 1/2 in. and hooks over the top of teeth resting on 1 tooth ahead and 1 behind the raker you are working on so it is just as easy to use on either side. Slick $11.00 plus tax (Can$)
I think it is possible that the older lower rpm saws maybe harnessed the power better with lower rakers than the newer free revving saws.
Question how small an area should you leave as the tip of the depth guide. If it is brute flat it will have a different control factor than a tip contour that is rounded up and tapered from both sides like it is on the factory chain. A little more pressure then will force it down into the wood some and act like a lower setting. This is guessing on my part.

Frank

 

[z4lunch]

Hey Frank,
Steve here... How 'bout a pic of that gauge
Steve

 

[Crofter]

Digitally Challenged

Sorry Steve; I am going to fiddle around to see if I can get some close ups with my film camera of some of the chain I'm dinking with and will shoot the adjustable depth guage too and scan it in. No promises though. It is the easiest depth guage I have used as it really stays put since you can squeese it against the side of the bar and it is then not sliding all over your freshly sharpened teeth like with the little ones you perch on top of the teeth.

Frank

 

[Kneejerk Bombas]

Frank,
Break down and buy a digital camera.


They are loads of fun.

 

[Fish]

So where are the gurus?

 

[Tony Snyder]

Fish you are the guru, you are just trying to bait someone.

Back to depth gauges; when I find someone who seems to care about them, I try to sell them Carlton Chain and the file-o-plate.

I got a logger customer who runs the biggest saws he can buy, he is not real brand particular but its just gotta be big. He immediately knocks his drags down to .040 or more.

 

[Gypo Logger]

Walt was never around when you needed him. I think he went back to fly tieing.
John

 

[Crofter]

Adjustable Depth Guage

Got a pic of this guage; don't know how new it is or where all its available but it seems much nicer to use than the little hold on toppies.

Frank

 

[Kneejerk Bombas]

That looks like it depends on an average of the heights of the teeth in front of and behind the depth gage, rather than just the single tooth you are working on.

 

[Crofter]

You are right Mike in that it is a factor of the two teeths height but not an average as you are much closer to the tooth whose raker you are guageing. The same relationship is there with the other type that also rests on top of two teeth; the one you are working on and the one behind it.

I'll try another pic of the square filed tooth here.

Frank

 

[jokers]

Hey Frank, it looks like your doing really well on your square filing. Russ

 

[crowe]

Crofter,
That is a pretty neat depth guage I might have to try find me one of those. Talking about raker clearence though I have always been partial to .30 th in the summer and .25 th in the winter. If it wasnt for a few hardnosed trees like hickory and hard maple I would probably run .30th all the time. Most days I file once in the morning and I am good for the rest of the day I generally cut anywhere from 40-60 trees depending on what the ground is like. I also keep trees clean of moss and dirt with my axe. Moss can trap a lot of dirt. Anyway later....Wade