Skiptooth chain

[ripplerider]

What are the pro's and con's of using full skip chain? I've always used full comp but I'm open to change. Less teeth to sharpen would be a big plus for me, especially since I broke a finger last weekend. Thinking about putting a 24" skiptooth bar-and-chain combo on my 660. I would definitely be cutting a lot of hardwood with this setup. Any advice?

 

[MacLaren]

To me personally I would stick with full comp on a 24 cuttin hardwood. I may use a full skip on a 28. I think its personal preference that counts. You would prolly be fine goin with a full skip on a 24. Maybee you could go with a half skip. I honestly think you would be fine with either full half or full just as long as you keep your chain sharp.

 

[MacLaren]

Im no expert but I imagine the cons to a full skip would be just a hair slower than full comp but on the other hand less teeth to file as you mentioned. Thats about all I can think of. Gve it a whirl. I like full skip, as Ive even used a full skip on a 20" bar and it cut like a madman

 

[imagineero]

there's no such thing as a free lunch.

Using full skip chain only gets you half as much work done between sharpenings as full comp, so it's not of great benefit. If my saw has the power, I'll choose full comp every time. The real benefit to semi or full skip comes in when you're trying to drive a huge bar with a smaller power head, try 60" on a 660 for example. If you can drive full comp on your given bar size, then go full comp.

Shaun

 

[MacLaren]

there's no such thing as a free lunch.

Using full skip chain only gets you half as much work done between sharpenings as full comp, so it's not of great benefit. If my saw has the power, I'll choose full comp every time. The real benefit to semi or full skip comes in when you're trying to drive a huge bar with a smaller power head, try 60" on a 660 for example. If you can drive full comp on your given bar size, then go full comp.

Shaun

I dont doubt what your saying one bit but when I put 20 " b/c one full comp the other full skip and didnt see much difference at all. I guess theres a big difference in cutting hardwood all day to make full comp 50% faster.

 

[Cedarkerf]

Not sure why a chain with a third less cutters would only do half the work? If this theory is true in timed cuts full comp should cut twice as fast as full skip. Bet ya your cutting speeds are gonna be with in 10-15%.
Full comp is much smoother especiely on smaller limbs and is faster.

 

[MacLaren]

Not sure why a chain with a third less cutters would only do half the work? If this theory is true in timed cuts full comp should cut twice as fast as full skip. Bet ya your cutting speeds are gonna be with in 10-15%.
Full comp is much smoother especiely on smaller limbs and is faster.

I had a hard time seein 50% gain from full skip to full comp myself.
I just didnt see it bein quite that much.

 

[corsair4360]

Why Skip vs Full Comp

This debate is interesting. Emotion aside, there are real engineering reasons for skip tooth chains.

My training is as a forester (long time ago). I did some research in the design of saw blades (circular) that really gave me a different perspective of a saw tooth. The space between teeth needs to be able to contain the chips from that previous tooth so they are not forced into the next tooth and "clog" it hindering its cutting effectiveness.

You can figure it out in general by calculating the volume of wood removed by the tooth (width x raker setting x length of the cut) and then take 115% of that as the actual volume needed. That is the equation that saw designers use as a rule of thumb for chip volume.

Example:

20" cut, 0.030 cut depth, 0.325 cut width with the 15% allowance for air in the chips comes up with 0.22 cubic inches of chips.

28" cut otherwise the same, chip volume is 0.32 cubic inches.

48" cut otherwise the same, chip volume is 0.53 cubic inches.

60" cut otherwise the same, chip volume is 0.63 cubic inches.

There comes a point somewhere between 24 and 36 inches where full comp chains cutting long cuts you need a skip tooth chain in order to provide a place for chips to be carried out through the cut to the end of the cut.

For my MS460 I have a full comp 0.325 chain that has 0.75" between the depth gauge and the preceding tooth. That works out to be 0.25 cubic inches. For my skip tooth chain the cutters are 1.5" between the depth gauge and the preceding tooth, which means it has 0.50 cubic inches. So for my 28" bar, I really don't need a skip tooth chain, but I have it. For a shorter than 28" bar, then full comp is the way to go. For longer than 28" I would recommend a skip tooth chain.

Hope that helps.

 

[pdqdl]

That's pretty good corsair, but that probably isn't the best reason or explanation for why a feller should use skip chain. I have "noodled" logs with my 3120 husqy, a 50" bar with full comp chain, and the noodles were literally pouring out of the chip ejection port.

Here is my take on it:
When you are cutting a 36" log with a 36" bar, you might have 30 cutters (just a wild guess) dragging across the wood at any time. This takes quite a bit of down pressure to make that many teeth cut into the wood, particularly if they are even a pinch dull. The longer the cut, the more you must force the bar into the wood to get the same size chips.

If you go to semi- or full- skip chain, you have fewer teeth contacting the wood, so the applied pressure per tooth is about what you need to make it all work right without wearing out the operator.

Furthermore, on a big cut with a whole lot of teeth dragging through a log, you really need a lot of horsepower. If you reduce the number of teeth buried in the wood with some skip tooth chain, you will keep the RPM higher, the engine stays cooler, the chips are bigger, and you finish the cut just as quick.

And you still don't have as many teeth to sharpen!

 

[imagineero]

I dont doubt what your saying one bit but when I put 20 " b/c one full comp the other full skip and didnt see much difference at all. I guess theres a big difference in cutting hardwood all day to make full comp 50% faster.

I might not have said that clearly enough ;-)

I didnt mean that full comp is faster than skip, the speed of cutting comes down to how many teeth in the cut, how sharp the teeth are, whether the saw is powerful enough etc.

What I meant is that full skip (skipping every other cutter) will get half as much work done between sharpenings. Since there are only half as many cutters on a full skip chain than a full comp, those teeth are going to be blunt in half as much wood cutting as a full comp chain would get, so from a sharpening perspective I don't think you really come out ahead. Yeah it takes less time to sharpen the fewer cutters, but you'll be sharpening more often.

Semi skip on the other hand has an extra link in between each cutter, so 1/3 less cutters.

Interesting point about clearing out the kerf, but I havent run into any problems noodling all types of trees with full comp 36". We noodle the barrels down on most of our take downs on a daily basis to fit them in the chipper. Lack of noodle/chip clearing in the kerf has never been an issue though maybe it would on a bigger bar.

Shaun