iDRY Vacuum Kilns

Sponsors:

SKIP CHAIN

Started by KDJ, December 18, 2006, 12:38:11 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

KDJ

DOSE SKIP CHAIN CUT FASTER THAN REGULAR FULL CHISEL? THINKING ABOUT BUYING SOME FOR MY 7901 MAKITA. MAINLY CUT OAK AND ELM.

KDJ

leweee

No & Yes .....No if you are useing a short bar....Yes if you are useing a long bar(over 24") ;D
if you have the power to pull full comp it will cut faster.....in big wood, skip keeps the chain speed up for limited horse power....with out Bar- B- Qen the clutch. ::)
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

Simonian

Skip on long bars ?
Does the skip help clear the chips from long cuts on bars over 30"
I have never been able to have a good look on what is going on in the middle of a long cut. but just guessing by the discharge that a full comp chain would bog down more from the load of chips than the cut.
The cutters may even be cutting the chips again, if they do not clear quick enough.

Ianab

My take on this question is that each set of cutters takes a certain amount of power to drive it through the wood. Say it was 1/2 hp for example, so a 6hp saw could keep 12 sets of cutters working properly. Now if you put on a longer bar (and bigger log) and try and work 24 cutters, you dont have enough power. The saw bogs down, you have to lift the bar off to keep the revs up and you cut much slower. In that case a skip chain would be an advantage, you keep the lesser number of cutters working properly.
Skip chain on a small bar will be slower because each cutters 'bite' is controlled by the chain's rakers. Just because you have less cutters and power to spare wont make the teeth take bigger bites.

So the question is where do you swap over?

I run full comp on my ps7900 with a 28" bar, but cut mostly softwood. It has the power to drive that, but maybe in hardwood a skip chain might be better? If I get a 36" bar I would run skip on it for sure. A 20" bar should allways be full comp (on this size saw anyway)

Chip clearance and the power lost just by having more chain to drag over the bar must come into the equation too, but thats my simplified understanding.

So my answer is yes and no too.

How long is your bar and how big is the wood?

Cheers

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Simonian

Say it was 1/2 hp for example
This would be very interesting to know. What is the drag of each cutter and how much HP does it take to move it along at 55 MPH.
1/2 HP may be very close
I think I have an idea

Simonian

13 skip cutters on a 32 bar powered by a Jonsered 2083
6 hp /13=.461 HP per cutter
13 cutters on a 20 inch bar powered by a Jonsered 2054
3.5hp/13=.269 HP per cutter

If this is correct "3.5hp/13=.269 HP per cutter" then all that is needed is just a little more than ¼ HP to drive any sharp cutter through wood at 55 MPH
Then the 2083 using twice the power for each cutter. Now it is possible to use full sequence chain on a 32 inch bar. The only way to know for sure is to do it.
The question now is Will the chips clear fast enough ? 

MDP

Go with semi-skip you get the best of both worlds.

Mark

blaze83

I run skip on my 044 with a 28" bar,  I got tired of filing full comp when ever I'd dull the chain...seems as though the teeth would never end :D maybe I'm the only guy on here that has to file on ocasion smiley_whacko
I'm always amazed that no matter how bad i screw up Jesus still loves me

Raphael

  After milling ~10mbf with a chainsaw you get pretty quick with a file... Or at least so numb to the process you don't notice the time.  :D

  I like the semi-skip suggestion, I think it would work well on my saws (066 & MS660) for bars in the 28-40 inch range.
... he was middle aged,
and the truth hit him like a man with no parachute.
--Godley & Creme

Stihl 066, MS 362 C-M & 24+ feet of Logosol M7 mill

Al_Smith

 It's just a matter of choice and what you are cutting.I have both full comp and skip I use on 36" bars on 100 plus cc saws.Here in the hardwoods I really don't see much difference.

Now then,perhaps it was the mid 70's ,Oregon made some skip,chisel in 1/4" believe it or not,for small saws.I ran a few loops on a little Poulan s25.It did cut faster than the usual chain.Thanks to Ralph Nader and his bunch they took it off the market.It was alledged that the buying public was being over charged due to fact the price was the same as full comp chain but only half the cutters.

rebocardo

> It was alledged that the buying public was being over charged due to fact the
> price was the same as full comp chain but only half the cutters.

Maybe Ralph should have been forced to find a way of using only 1/2 the drive links too   ;) 

My testing with my Husky 365 and I cut mostly white oak

20" bar = full skip or full comp = no difference I could see. It did make it grabby and sort of dangerous for cutting small branches and stuff, especially if not attached to the tree on short pieces. So, I use full comp on 20". I did not notice any vibration difference.

28" bar = full skip (30rcs) and full comp (Oregon 72V and other safety chain). Full skip MUCH faster in oak, especially buried in a 24"-36" log. I don't know about softwood speed, I do not cut much. The 72V slowed down enough, bogging, so it was more burning the wood then cutting it because the cuts were taking too long.

28" full skip is much faster to sharpen, especially by hand!

Allison

It depends what sort of work you're doing and what size bar your running.
I run skip on my Stihl 460 with a 32" bar for cutting hardwood works well but if I'm cutting smaller diam. stuff I run full comp even on the longer bar. I don't like to bend over all day and that extra reach is handy. In 18" & under full comp is just as fast and doesn't grab as much when I'm limbing.
I have an 084 for big stuff ( 42" bar) and only run skip on that for felling or bucking.
When I run it in the mill I've tried Granberg and Oregon ripping chain.
Give it a try watch for extra kickback!!.
Be safe,
Allison :) :) 

leweee

Welcome to the Forestry Forum Allison. :)
Looken forward to seen pics from down under....and the outback. ;D
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

Allison

Well Lewee you might get some pics if it doesn't all burn this summer!!
One fire in Victoria alone is up over 2.5 million acres already and they won't stop that till the new year.

Be Safe,
Allison :) :)

leweee

 :( sorry to hear about the fires. Has this much of Victoria ever burned before?
What part of Victoria ya from ,If you don't mind me asken?
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

parrisw

I run a 394xp with 33" bar, and a full comp chain, .404 .058 chain, and it seems to have no trouble at all running it, I just cut up a 30" Oak with it, with no power issues.

Thank You Sponsors!