chain sharpening questions

Ashful Posted By Ashful, Apr 19, 2013 at 11:06 PM

  1. Ashful

    Ashful
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    1. I accidentally knocked just one depth gauge down too far on one of my RSC chains today, while experimenting with grinding depth gauges on the grinder. By too far, I don't mean a few thousands of an inch. It's half gone! Is it a bad idea to continue using a chain with one depth gauge mostly gone? All the rest are set at 0.025".

    2. I tried grinding a wee-little H36 chain for my Husq.T435 for the first time tonight. The recommended top plate angle (right from the Husqvarna T435 manual) for the factory chain is 80 degrees! I ground a few teeth on the factory chain (green label crap) to that, and it just looks all wrong to me. My other chains for that saw are Stihl Oilmatic 63 PMC-3 52's, and they look like they're sharpened to the same 60 degree top plate / 30 degree vise angles I use on my RSC chains. What gives?
     
  2. bogydave

    bogydave
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    Grinding the rakers low of might make your saw cut faster if it has enough power.
    Give it a try on some softer wood of green stuff. Should be OK.
    Speed cutter guys take the raker off to make faster cuts, lots of HP though.

    Is it the same as the Oregon 91VG ?
    try here (bottom of the page) : http://www.oregonproducts.com/pdf/chain/91VG_F&B.pdf

    . I use a file :)
     
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  3. HDRock

    HDRock
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    If it is just one depth gauge short , I don't think it's a worry about thing, but , others, correct me if I am wrong.
     
  4. NH_Wood

    NH_Wood
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    Maybe a little more vibration in the cut? Can't see anything dangerous, but never had a chain with one short raker. Definitely seems off on the file angle recommendation - teeth must have looked way off at that angle, unless I'm misunderstanding your post. Cheers!
     
  5. bogydave

    bogydave
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    I'm with you.
    Just one ground down should not even be noticed .

    I was thinking the whole chain was that way. ;?
     
  6. BobUrban

    BobUrban
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    Just one will not be a problem and likely un-noticable. If you feel there is a real concern you could gring the tooth off and just eliminate one entirely but that is an extreme solution to a very minimal problem - if considered a problem at all.
     
  7. Havendalefarm

    Havendalefarm
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    If, by chance or on purpose,you do get the rakers down a little then be prepared. One raker will not matter but if you do them all it WILL cut faster as each tooth is taking a deeper cut. But BE CAREFUL it will also kick back a LOT harder. I use a 372xp with a 16" bar and chain filed in this manner for blocking large quantities of firewood and it is not something for an inexperienced cutter.
     
  8. Ashful

    Ashful
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    Thanks guys. I figured as much. Unless that sole tooth happens to hit something rounding the nose, it likely doesn't matter.

    The bigger question was the top plate angle on the H36 and PMC-3 chains! ;lol
     
  9. MasterMech

    MasterMech
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    Many semi-chisel chains specify a much steeper angle than their full-chisel counterparts. Stihl RM series chain included.
     
  10. smokinj

    smokinj
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    On those long chains I would never use the grinder. It makes a very bumpy ride down the road. I just use a file and keep them looking factory round. Flat rakers on a lone bar will give you tennis elbow! :eek:
     
  11. lukem

    lukem
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    You're not going to notice one raker being to low. No worries.

    I file my rakers by taking the top down to the right height (as measured by my gauge), then a couple extra passes on the front to get the slope right. Takes me way longer to do the height and angle at the same time...I don't have the knack for it.
     
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  12. smokinj

    smokinj
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    Roll the file right over the top of the raker.
     
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  13. Ashful

    Ashful
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    Can anyone please decode this chart?

    http://www.stihlusa.com/WebContent/CMSFileLibrary/instructionmanuals/USG_sawchainangles_chart.pdf

    For example, what is the top plate grind angle setting for the PMC3 chain? Looking at the diagram of their machine, I would say that's angle "A", or 40°. However, looking at the right-most column, I would say it's 75 degrees. I've not ground any chain to 75 degrees yet, but it does more closely match the Husq. H36 spec of 80 degrees I mention in the OP.

    It seems clear to me the vice angle must be 30 degrees. No idea on vice tilt, unless that's the +/- 15 number, which my machine can't achieve. Also, no idea on what all the +/- 40 degree numbers are in column A.
     
  14. MasterMech

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    That chart looks like it's specific to the Stihl USG grinder. I'll look at it more later.
     
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  15. Ashful

    Ashful
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    Thanks, Master Mech! That's what I got from it, as well. Unfortunately, I cannot find ANY literature that defines the three angles for a PMC3 chain:

    1. Top plate
    2. Vise angle
    3. Vise tilt

    I'm assuming these might be 75 / 30 / 15 degrees, but would like to know before I grind.
     
  16. smokinj

    smokinj
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    Most grinder will always be 60 tilt 30 degree angle and some will call for vise tilt of 10. I never use the vise tilt. So 60/30 on all ripping chains and 60/25 on the pico chain and 60/10 on milling chain.
     
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  17. Ashful

    Ashful
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    Cool. Thanks, J. I was thinking of doing just that, but wondering why so many seem to be calling out 75 - 80 degrees head tilt on the pico.

    I do sharpen all my standard chains at 60 / 30 / 10 degrees. Yeah, the 10 on the vise tilt makes it dull quicker, but it cuts wicked fast with that hook, too!
     
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  18. smokinj

    smokinj
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    With the pico its a bit in the butt to clear the top of the cutter. With the 75 probably just letting it slip past it easier. I never lock my vise when doing them because you have to lower the wheel then slide the chain into place. My chain over 5 years old now it it called for 60 then, could be quicker. I will try it next time.
     
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