How is the lo-pro crew doing depth gauges for milling? I picked up a westcoast saw 3/8 LP gauge and took the rakers down to their highest setting (.025) and HOLY **** this thing is so grabby I can barely put any pressure on it. They either have their measurements all messed up or we need to be closer to .010-.015 for smooth milling. Everywhere else I have looked has the same depth options and nobody offers a .020 or .015 gauge. How are you guys dealing with this?
Depth gauges for 3/8 lo pro milling
- Thread starter chunez
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solserenade
New Member
I haven’t used the Westcoast gauge on 3/8 lp yet - But, I just happened to get a couple of ripping chains from Granberg today.
The included instructions specify .025” depth for 3/8 lopro (for their chain).
Can you cross-check your results with a different depth gauge or dial indicator to confirm you’re at .025”?
The included instructions specify .025” depth for 3/8 lopro (for their chain).
Can you cross-check your results with a different depth gauge or dial indicator to confirm you’re at .025”?
calling @Coralillo Lo Pro
Dropping rakers by a fixed amount (eg 0.025") is a pedestrian way of operating. The rakers should be nominally dropped by approximately 1/10th of the gullet (gap between cutter and raker) width. The 0.025" setting is a nominal one for a new chain but as the cutters get shorter the rakers should be dropped even more below the cutter. eg when the gullet is 0.5" the raker should be dropped 0.05" below the cutter. This maintains a constant cutting angle as the chain wears and ensure optimum performance for the life of the chain.
Instead of talking about the amount of "raker drop" it makes more sense to to talk about raker angle - angle between wood/cutter tip and raker top. A 0.025" raker drop on a new (gullet 0.025") cutter translates to a raker angle of about 6º. But 6º is just a basic guide the angle to use depends on many things including the saw, wood hardness and width, bar length, chain etc . On my 441 with the 25" bar and lo-pro chain I use a raker angle of 7.5º which corresponds to a raker drop on a new chain of about 0.033". Just keep the revs up and it cuts like a hot knife through butter even in very hard Aussie wood. On my 880 with the 60' bar and 2/8 full comp chain I use 6.5º. A member of this site cut timber for his whole barn using a 660 with a 36"? bar and full comp chain used 9º!
Nothing is free so at higher raker angles there will be much more vibe and B&C wear is and auxiliary oiler is not used with plant of flow.
For more detail there's a super nerdy thread about this I started in 2009 in the hot saws sub-forum on sharpening
https://www.arboristsite.com/threads/are-fop-really-progressive-depth-raker-generators.114624/
Instead of talking about the amount of "raker drop" it makes more sense to to talk about raker angle - angle between wood/cutter tip and raker top. A 0.025" raker drop on a new (gullet 0.025") cutter translates to a raker angle of about 6º. But 6º is just a basic guide the angle to use depends on many things including the saw, wood hardness and width, bar length, chain etc . On my 441 with the 25" bar and lo-pro chain I use a raker angle of 7.5º which corresponds to a raker drop on a new chain of about 0.033". Just keep the revs up and it cuts like a hot knife through butter even in very hard Aussie wood. On my 880 with the 60' bar and 2/8 full comp chain I use 6.5º. A member of this site cut timber for his whole barn using a 660 with a 36"? bar and full comp chain used 9º!
Nothing is free so at higher raker angles there will be much more vibe and B&C wear is and auxiliary oiler is not used with plant of flow.
For more detail there's a super nerdy thread about this I started in 2009 in the hot saws sub-forum on sharpening
https://www.arboristsite.com/threads/are-fop-really-progressive-depth-raker-generators.114624/
A progressive raker gauge like the one I am using accounts for the increasing gullet gap as the chain wears. I understand what you are saying about the attack angle but it begs the question: what gauge are you using to measure this reliably? Especially in a stump vice, in the bush sharpening setting. Are you really taking a digital angle finder and setting it on every tooth before you file then checking your work?
solserenade
New Member
Bob L (and the FOP thread) has me convinced it’s worth a $30 investment in the digital angle finder - not for ‘in the field with a stump-vise’ - rather, at home in a proper vise. Zero it on the bar, then check the chain (in the bar) with the DAF. It’s also a way to confirm the progressive depth gauge is leading to the desired cutter/depth-gauge angle. It should also tell me the new chain ‘specs’ (angle), and if I happen to be using the depth gauge incorrectly.
Can't improve on Bob's painstaking explanation of all things raker, but I will say I have never used 3/8LP that was "grabby". It does cut so effortlessly it flies through the cut on autopilot, I never really have to push it, but isn't grabby, it's smooth as can be. I have yet to sharpen any of my LP chains more than a few times, and with a Stihl/Pferd 2 in 1 for 3/8LP chain. Has taken the rakers to .025 I believe. Never a problem. What kind of chain? I've been either using Panther from the UK or just started making loops from Archer. Happy with both.
Yep, that's it, set the rakers in the shop and develop a field filing pattern that suits. Touch up cutters (3 file swipes) after every tank of mix, touch up rakers (no measurement - 2-3 swipes) after every 3-4 tanks. This usually works for 6.5º rakers on full comp 3/8.
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