Thread: Home made full complement ripping chain

Originally Posted by Travis Edwards

Made my first ripping chain today. My local suppliers do not carry proper ripping chain and I have a bar that I bought specifically for milling which came with three chains, and as I have no intention of using this bar for crosscutting or felling I thought I may as well modify at least one of the chains to see how it goes. It took me about an hour to do but I reckon I could do it quicker now and I don't reckon I need the chain grinder just a file and a dremel.

I gave it a run and was Very impressed with the required hp reduction and how much better the finish of the cut was. I only cut with it freehand today as I have not finished my rail mill yet but I think it should be good. I made the chain to be similar to the Granberg design with 2 scoring cutters and 1 raker cutter. It is a full complement chain not skiptooth

here is some pics https://www.woodworkforums.com/member...ripping-chain/

I got my inspiration from this link http://www.arboristsite.com/showthread.php?t=35585 I do not know how big a chain this guy was doing but he reckons it took him 4 hours to do one chain I reckon I could do it in about 30 to 40 minutes for a full complement 84 drive link chain, now that I have done one. I have a few more experiments I wish to do with this chain before I will say I have perfected it however, I.E. raker heights, length of scoring cutters relative to raker cutters etc.

I must say that I was impressed with how smoothly it entered into the cut, no jumping or chattering and straight into kerf size. At the moment I have left the scoring cutters slightly longer to see if it has any effect on the way it cuts or the finish of the lumber but as I said I will experiment a bit with this.

That guy is the famous "aggiewoodbutchr" from the milling forum on Arboristsite. Aggie's modified GB mill is what I used as a starting basis for my mill. He uses 60 and 72" bars.

These original granberg designed ripping skip chains were developed by Will Malloff for soft woods. Even if it is still full complement I am somewhat reluctant to try them in Aussie hardwood because I just have a gut feeling that in Aussie hardwood, the more cutters one has applied to the wood the longer they will last before they will need resharpening. Nevertheless I am prepared to be convinced otherwise. I will be interested to see how you go long term with the sharpening.

BTW what top plate angle did you use?

I am not too worried Bob, The chain cost me bugger all and gives me the opportunity to see how it goes. I plan on trying it out on some blackwoods over the christmas break, These will be green ones however but I will be interested to see how it goes. I tried it on some local hardwood today and it cut beaut. Granted it was very green, was a living tree last weekend, but it worked well. As for lasting longer between sharpens would that not be a good thing?

With the cheap crud chainsaw grinder I have the best I could get was around 7 degrees for the raking cutter, but I will try filing to less than that eventually. I have started with around 25 degrees for the scoring cutters but I will experiment with that too.

Originally Posted by Travis Edwards

I am not too worried Bob, The chain cost me bugger all and gives me the opportunity to see how it goes. I plan on trying it out on some blackwoods over the christmas break, These will be green ones however but I will be interested to see how it goes. I tried it on some local hardwood today and it cut beaut. Granted it was very green, was a living tree last weekend, but it worked well. As for lasting longer between sharpens would that not be a good thing?

My thinking was more raking cutters means the raking cutters would last longer. Removing raking cutters would place a greater load on the remaining raker cutter edges meaning they would go blunt quicker, but it probably is not that simple.

I think what you have done is the same as a Granberg Ripping chain which uses full comp chain - note the use of 0 - 5º top plate angle.
See Granberg International - Home Page


I also note that Granberg use raker depths on the scoring cutters of 0.040" compared to the raking cutter rakers of 0.030"
In some ways this does not seem right to me. The scoring cutters are narrower so with an added greater raker depth (or cutting angle) they should penetrate much further into the wood than the raking cutters. I think this represents wasted energy and if anything the scoring cutter raker depth should be a little less than the raking cutter raker depth.

There is also the possibility that a full comp granberg style rip chain won't use the scoring and raking cutters in as effective a manner as when used in a skip chain configuration. The reason for this is that cutters on a chain do not act completely independently of each other, Cutters act in waves of 2, 3, 4, or 5 consecutive cutters. The first cutter to grab initiates the start of a wave, the next cutter grabs a little more wood and then (depending on a lot of factors) the next cutter grabs even more, until chain tension pulls all the cutters back to the bar. The cutters porpoise up off the bar to do this.

If the first cutter to grab the wood happens to be a raking cutter then the scoring cutters that trail behind are not doing much if anything. Maybe this is why Granberg make the scoring cutters have greater raker depths - but this does not matter if by chance a raking cutter has grabbed the wood first. Then your idea of leaving the scoring cutter taller is superior because the taller scoring cutter will always grab wood first - but instead of the first scoring cutter it could be the second that grabs first and thus the first one is not doing its job. Being taller scoring cutters they will also wear quicker and continual sharpening to a "no glint on edge" spec will pull them back to the raker cutter heights.
It sure is tricky to force scoring cutters to be the first in a cutting sequence.

One possibility is to use skip pattern sequencing because if the skip is long enough (two or more skipped cutters) this automatically assigns the start of a cutter sequence.

Here I make SC = Scoring cutter, RC = Raking cutter

Thus a sequence like LSC, RSC, LRC, skip, skip, RSC, LSC, RRC, skip, skip, . . . . would force the cutting wave to start with a pair of scoring cutters followed by a raking cutter last in the sequence. If I was to try anything in this space it would be something like that.

Clear as mud?

this shows the finish and the chips from this chain. remember this is freehand.

https://www.woodworkforums.com/member...-finish-chips/

Originally Posted by Travis Edwards

this shows the finish and the chips from this chain. remember this is freehand.

https://www.woodworkforums.com/member...-finish-chips/

Some of those look like regular noodles to me.
Cutting noodles is always WAAAAY easier than cutting cross grain as in normal milling.

Originally Posted by BobL

Here I make SC = Scoring cutter, RC = Raking cutter

Thus a sequence like LSC, RSC, LRC, skip, skip, RSC, LSC, RRC, skip, skip, . . . . would force the cutting wave to start with a pair of scoring cutters followed by a raking cutter last in the sequence. If I was to try anything in this space it would be something like that.

Clear as mud?

Yes I did look at the granberg website before I did make the chain And yes I did deliberately leave the scoring cutters longer on purpose as I assumed if the scoring cutters were cutting deeper than the raker then the amount of timber that the raker has to remove is not as great thus further reducing the hp required to drive it.

I like your sequence above and depending on how this chain goes I will try that.

Originally Posted by Travis Edwards

Yes I did look at the granberg website before I did make the chain And yes I did deliberately leave the scoring cutters longer on purpose as I assumed if the scoring cutters were cutting deeper than the raker then the amount of timber that the raker has to remove is not as great thus further reducing the hp required to drive it.

A bit of extra depth scoring will also help the raker cutters a lot in cross grained hardwood.

To really benefit from this modification I would work with specific cutting angles rather just a pair of set raker depths (ie 0.040 and 0.030 as used by Granberg).

Something like
8:1 (gullet raker depth) for the raker cutter
AND
6:1 , for the scoring cutter
These represent cutting angles of ~7º for the raker cutter and 9.5º for the scoring cutter. These are quite aggressive compared to regular cutting angles of 6º which give very good finish when used in combo with the 10 - 5º top plate filing angle.

I like your sequence above and depending on how this chain goes I will try that.

Excellent!

Originally Posted by BobL

Some of those look like regular noodles to me.
Cutting noodles is always WAAAAY easier than cutting cross grain as in normal milling.

Yes there are a few noodles in amongst it as I just sat the log on a stump about 2 inches tall The majority of the cutting was probably at about 70 degrees but towards the end of the cut I got more towards parallel with the log so that I could use the bar to stop the log trying to roll away. hence the noodles. the chips are from closer to vertical and are only around 1/2 the width of a standard chip.

Another theory i had about leaving the scoring cutters longer was that raker cutter was not cutting on the side of the cutter and only removing the bit of wood in the middle of the groove allowing the scoring cutters to plane the side of the cut Hence the reason I sharpened them to around 25 degrees like that of a hand plane. I would have liked to grind the raking cutters to less than 5 degrees (optimumly around 3) but the grinder wouldn't accomodate this. I personally think that this theory has worked as the finish is MUCH finer than if I had used a standard chain. Oh and on further checking The noodles are around half the width of of those cut with a standard chain, verifying the fact that the rakers are only cutting the centre portion of the cut groove, as only the rakers would be making the noodles.

the idea behind this chain is that the scoring cutters make the verticle cuts and teh raking cutter only makes teh top cut.

on a standard chain the top plates donot extend right to the oposite cutters side plate. so leaving just one raker it will not be cutting the full width of the scored timber. i belive you should leave 2 raking cutters one from each side.

teh scoring cutters also act as a guide. because tehy have no top pate they do not lift or pitch like a standard cutter teh more or les just scribe a streight line down the length of teh bar this gives a thinner kerf and a smother finish.

i tried using this style of chain for a wile and althow it was better than standard chain and left a nice finish. i found it to be slower than teh simple singel skip that i eventualy settled on using.

Originally Posted by weisyboy

the idea behind this chain is that the scoring cutters make the verticle cuts and teh raking cutter only makes teh top cut.

on a standard chain the top plates donot extend right to the oposite cutters side plate. so leaving just one raker it will not be cutting the full width of the scored timber. i belive you should leave 2 raking cutters one from each side.

teh scoring cutters also act as a guide. because tehy have no top pate they do not lift or pitch like a standard cutter teh more or les just scribe a streight line down the length of teh bar this gives a thinner kerf and a smother finish.

i tried using this style of chain for a wile and althow it was better than standard chain and left a nice finish. i found it to be slower than teh simple singel skip that i eventualy settled on using.

I found in the small test I did with it today that it still cut with acceptable speed maybe not quite as fast as standard or skip chain, But used very little horsepower in comparison to standard chain, I will endeavour to make a skip chain as well to do some testing and comparison with. as I have 3 chains to fit this bar and will only be using it for milling I will try your reccomended set up and depending on tests I will decide what to do with the third. may even go a combination of both the skip and granberg like bobl suggested. Horsepower use is probably my biggest concern and need to find what is going to give the best results in this regard. Finish is probably number 2 on the list then speed. 25 inches on an 034 is a bit to swing for a little powerhead and I will be looking at 30 inches when I finally get my rail finished so I will need to find what is going to be most efficient as far as hp goes. Running the 25 today with this chain cut much easier than a 20 with standard full complement chain. The true test will be when I try it out on some big blackwoods or redgum or something similar. With the ease of cutting today I actually wonder If I could step up to an 8 tooth sprocket to improve cutting speed in softer timber at least.

Originally Posted by weisyboy

the idea behind this chain is that the scoring cutters make the verticle cuts and teh raking cutter only makes teh top cut.

on a standard chain the top plates donot extend right to the oposite cutters side plate. so leaving just one raker it will not be cutting the full width of the scored timber. i belive you should leave 2 raking cutters one from each side.

teh scoring cutters also act as a guide. because tehy have no top pate they do not lift or pitch like a standard cutter teh more or les just scribe a streight line down the length of teh

Being an integral part of the chain with a hook and a raker the scoring cutters must rock and rise off the bar. As soon as any cutter (scoring or raker) contacts wood it initiates a chain wave. The wave length depends on many things including the number of cutters following the first cutter to make contact. If the scoring cutters didn't rock and rise off the bar they would have to be much (~3 mm) taller to do their job or it would not be worth having them at all.

As long as its raker has some decent depth even a zero hook cutter/scorer will rock and rise and score the wood - not very effectively but it will still do it. To further reduce rock and rise off the bar, the hook has to be at zero and the rakers below about 0.010". At this setting the cutter can grab very little wood and makes a lot of powder. To keep the cutter/scorer always on the bar the hook and the raker depth have to be zero or negative. At this point the cutter just sits on the bar and skates over the surface of the wood and will not cut anything. Any scorer/cutter continually sitting on the bar means it is ~3 mm away from the wood and not cutting anything.

It also doesn't matter if there is only one raker cutter following the scoring cutters as the following set of cutters will have the opposite raker cutter to clean things out. However, if this was a problem then a sequence like LSC, RSC, LRC, RRC, skip, RSC, LSC, RRC, LRC skip, . . . . would force the cutting wave to start with a pair of scoring cutters and have both a L and R RC to clear out the kerf.

Just a reminder that none of this is necessary to get a good finish. This is sugar gum cut with full comp 10º top plate filing angle.


Same chain but on Marri.


Same chain on a small lemon scented gum




Finish is very dependent on the operator, the stiffness of the mill, the power of the saw, the size of the log ,e length of the bar/chain and the chain configuration/profile.

you would need another skip in that sequence BobL or one less. With my small test today the rakers cleared quite fine. With the scoring cutters there is still a little top land left on them which will also help with the lifting BobL suggested. This can be seen in the other link I put in the first post in this thread and will also mean that they cut enough of a groove that the raker is still reaching from score to score.

Notice you edited the sequence there bob