Chainsaw Lumber Milling - Ripping Chain

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Ripping Chain

For best results when milling, you'll want to use a "ripping" chain. A ripping chain is a standard saw chain that has been modified for the purpose of milling. Typical modifications include regrinding the cutters to 0 degrees, removing some of the top plates, and lowering the rakers. A ripping chain can be made from any standard chain. But to maximize milling performance, select a professional-grade chain with a narrow kerf.

For those who would rather just purchase a chain, there are several sources available. I'm really not familiar enough with any of them to make a recommendation. If you'd like to make your own ripping chain, read on.

Professional, Narrow Kerf Saw Chain

By "professional" I mean a chain with no safety bumper links, no "vanguard" rakers, a square cutter profile, and a chain that's rated for a saw with 60cc's or more. By "Narrow Kerf" I mean a chain that makes the narrowest possible cut while in the wood. The wider the slot (or "kerf"), the more power that's required to sever the wood and remove the chips. Given the same saw power, a narrow kerf chain therefore typically mills faster than a standard kerf chain because it has less work to do. .404" pitch chains typically have the widest kerf, will require the most saw power, and will therefore mill the slowest of the common chain pitches.

I've used 3/8" pitch "Low Profile" chain with my 066 and found that while it does mill the fastest of any chain I've tried, it also isn't strong enough to hold up to a day's milling. Actually, I remember snapping two of these chains before milling a complete 18" Beech log. Maybe on a smaller saw or on a shorter bar, or with a smaller or softer wood the 3/8" low profile design would work well. I just don't know, though I may try again sometime.

The chain I use most freqently for milling is a .325 pitch, .050 gauge design with square cutters and a low profile (Sabre chain model 920). Unfortunately, Sabre chain is no longer manufactured. However, I'm fairly certain that other manufacturers make similar chains. There's absolutely nothing "wrong" with 3/8" chain, I've just found that it doesn't perform as well as .325" so I don't use it often for milling. .404" pitch chain will also mill fine, but because it has the largest kerf (and is heavy) I suspect that .404" would be the worst performer. In order to use a .325" chain, you'll probably need need to purchase a new rim or spur sprocket for your saw.

You'll probably also need to purchase a new bar or a .325" replacement sprocket tip for the bar you have. I use a bar with a roller nose design (no sprocket teeth) so I can run any pitch of chain I like. The roller nose design is also no longer manufactured, but if you ask around you can probably find someone with a few old stock bars in their storerooms. You could also use a bar with a hard nose design, which will accept a chain of any pitch. However, I've stayed away from this as I suspect that additional friction around the nose would take away from the power available for milling.

If you're going to use a bar longer than about 24", your should seriously consider using an auxiliary oiler. The auxiliary oiler works by providing additional bar oil to the chain , near the tip. The additional oil can reduce bar and chain wear, extending the life of both. The auxiliary oiler is generally a small tank of bar oil (a pint?) that's mounter near the top of your Alaskan. Bar oil runs down down to the bar through a small tube. In a typical setup, each side of the bar is drilled with a hole along the rail near the tip (outside of where the Alaskan clamps to the bar and not part of a replaceable tip). The hole is about 5/16" in diameter, and should be located just far enough away from the edge of the bar so as to be mostly in the solid bar but just break through into the chain groove (maybe 1/8th the diameter should break through into the groove).

Bar Oiling tips:
  • A thinner bar oil is generally better than a thick one for milling. Some manufacturers sell a "winter blend" of bar oil which is thinner, and it can be used all year 'round for milling.
  • Many saws have an adjustable automatic oiler. If you have one, turn it up to the maximum setting for milling.
  • Many newer bars have a small, angled oiler hole to deliver a trickle of bar oil to the chain. If you bar has one of these, drill out the hole to oversize it. Do both sides!

    Chain Selection

    Start by selecting a standard chain that will work well as a ripping chain. First, you'll need to decide what gauge and pitch you'll be using, then the cutter style. If you'll be matching a chain to whatever bar you have, the pitch and gauge will probably be dictated by your bar.

    Regrinding

    If you look down at the cutter of a standard saw chain, you'll see that the sharp leading edge of the top plate is angled about 30 degrees from perpendicular to the direction of chain travel. On some brands of chain, there's an etched "witness mark" towards the back end of the cutter to help you file at the correct cutting angle.

    For ripping, you'll want to re-grind this to a much smaller angle. That is, re-grind it so that the sharp edge of the cutter is closer to perpendicular to the direction of chain travel. A smaller angle will take more saw power to pull the chain through the cut, but will also leave a smoother surface on the milled boards. Some would say to regrind to 0, 5 or even 10 degrees, depending on the type of wood. I haven't done any controlled testing on this, but I've read that 0 degree cutters tend to stay sharp longer in hardwoods and that 5 to 10 degree cutters mill faster in softwoods.

    Top Plate Removal

    Some manufacturers of ripping chain actually grind off all or part of the top plates for every other pair of cutters. The reduced/removed top plates (called "scoring" cutters or teeth) are typically re-ground to 15 or 20 degrees. The idea is that these scoring teeth will sever the wood, and then the cutters with the full top plates will cut and clear the wood chips. By removing part or all of the top plates, you reduce both the milling speed and the amount of power needed by the saw head. This may help when milling with a smaller saw. If you have 120cc's, you probably have enough power to leave all of your cutters at 0 degrees.

    Lowering the Rakers

    Rakers are the little nubs that stick up right in front of each cutter. Typically, one is supposed to use a raker file and a special raker depth gauge to maintain a depth of about .025" from the top of the highest point on the cutter down to the top of the raker. With Ripping chain, this depth can typically be increased. There's no hard and fast rule, but going to .030 or .035 seems like a good idea. If you've ground scoring teeth into your chain, set the rakers on these .005 lower than on the cutters with the full top plate (e.g. .035 or .040).

    If you have questions, (Yahoo's Milling Group is an excellent source of information on chainsaw lumber milling.)


    This page was last updated March 10, 2004
    by bCentral