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Thanks for posting all the comparison info on the chains. I'm glad someone is taking some scientific data. Most of the comparison I notice is between my usual free hand file before and after hitting a nail in a yard tree. Hitting all these nails prompted me to buy one of the Oregon grinder rip-offs from Northern Tool. For now I'm just getting the hang of getting consistent results but later maybe I'll start experimenting.

Yes he advocates a winch, but it also seems he never heard about using slope to advantage.

Seams like the cool thing about a winch is that it can get you away from the exhaust and dust. I built one but decided it was too much hassle to use.
Slope is nice too but I don't find that it pays back enough to go to too much trouble to create it. I've never thought that leaning on the mill to push it through was all that tiring but then again I just turned 30 so maybe I'll change my mind.
 
Seams like the cool thing about a winch is that it can get you away from the exhaust and dust.
My 076 and 880 setups blows the exhaust away from the operator so that's not a problem for me and I'd rather be in physical contact with the mill than on the end of a rope or a long handle but other operators don't seem to mind that.

I built one but decided it was too much hassle to use.
Slope is nice too but I don't find that it pays back enough to go to too much trouble to create it.
I guess if you don't mind pushing you don't mind bending over either.
Like I said, without knowing it the 72 lb 880 in the BIL mill = 20 lbs of forward force on a 15º slope so no wonder I don't need to push.

I've never thought that leaning on the mill to push it through was all that tiring but then again I just turned 30 so maybe I'll change my mind.
Maybe you don't mind milling on your knees either but somewhere between now and double your current age maybe you will say why did I do it that way?
 
My 076 and 880 setups blows the exhaust away from the operator

I'd like to see how you did this with the 076. Is there a post you can send me to were you describe it?

I don't like bending over to pick something up but bending to push on something doesn't seem to cause me trouble. I do try to keep my back straight during the milling procecs but dropping into a crouch or getting on my knees if I have to doesn't bother me either. If I can't get the log off the ground the dust and exhaust tend to be the killer.

I've been on summer vacation from school so I've done quite a bit of milling and my back feels great. I'm about 2/3 of the way through a masters of electrical engineering and what kills my back is studying if I'm not careful. I like to study by working design problems that take an hour or so each. My tendency to slouch over the paper feels comfortable until I try to stand up again afterward and find myself walking with a limp. School starts on Monday so I'll be working on my posture.

Today I was milling some old growth larch in the forest behind my parents house in Idaho. The tree I was milling was cut by loggers and just left laying next to the stump. I don't know why they just left it but the last logging here was done in 1943 so it's been cut a long time but I wanted to see if i could still salvage some wood from it if possible. I got some nice slabs but at times the progress was really slow going. When I looked at the chain the gullets were filled part way in with dust and the 'sharp' part of the cutters was so caked that I'm not sure how it cut at all. Although there were some punky areas in the log it was mostly sound. Could it have been the punky spots that caused the chain to cake up? This was with standard skip tooth on the 066 because I only brought milling chain for the 075 but had to order a part for that saw. I'm not sure what I did with my camera so no pictures:confused:
 
I'd like to see how you did this with the 076. Is there a post you can send me to were you describe it?
sorry if you thought I'd done something to the 076, the standard exhaust blows away from the operator if they stand in the usual milling position.

Could it have been the punky spots that caused the chain to cake up? This was with standard skip tooth on the 066 because I only brought milling chain for the 075 but had to order a part for that saw. I'm not sure what I did with my camera so no pictures:confused:
Most chains will mow thru punky wood, unless its got some grit in it from say termites or other bugs and then even though it might be soft it will slow you down quickly.
 
Haven't had a chance to go milling again yet, but my DAF showed up and I've been learning to use it on chains.

The first thing I learned is that it would be handy to have a "real" chain vise. I have been using an old bar to hold chains for measuring and filing, but the slight curvature of the bar throws off the DAF measurements. For now, I just put a mark on the bar, leveled the bar at the mark, and did all my measurements at the mark.
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In case anyone wants to check the DAF with photoshop, here's the same chain/link without the DAF in the way.
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To measure a chain that is installed on a saw, I clamped the bar, saw and all, in a vise, marked a spot, laid a straight edge over the cutters at that spot, and zeroed the DAF on the straight edge.
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In general, I had a hard time getting consistent results with the DAF, plus there was a surprisingly large variation from one cutter to the next, even though my chains are done on a grinder and the grinder does a far more consistent job than I could ever do by hand (a virgin factory chain also showed quite a bit of variation from one cutter to the next). I suspect it is just inherently difficult to measure the angle over such a short distance, especially when the surfaces are pointy and non-flat.

Then I tried a different way of measuring the raker angle using calipers. The last time I used calipers to measure rakers, I had laid a straight edge across the top of the cutters, and measured down from the straight edge. It was tough to get consistent measurements that way, and a certain Aussie questioned my results. :laugh:

This time I measured from the top of the cutter (or raker) to the bottom of the link. Even though the bottom of the link was slightly rounded and peened, I was still able to get pretty consistent measurements this way.
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Some DAF results, bearing in mind that this was my first outing with the DAF and I'm still getting the hang of it:

Virgin 33RC -- 5.5 degree raker angle

FOP'd 0.325 -- 5 to 5.5 degree raker angle (it has been my experience that the 325 FOP is not aggressive enough).

FOP'd lo-pro -- 4.5 degree raker angle -- and yet the lo-pro FOP is a little too aggressive. Maybe it has more kerf PSI due to the narrow kerf ?

Experimental GB'd 3/8 milling chain -- 5 to 6 degree raker angle on regular cutters, 5 degrees on scoring cutters, even though I had ground more off the scoring cutter rakers. Doesn't make sense, but that's what the DAF said.

Experimental 33RP #1 -- 6 degree, even though this had been dressed much, much more aggressively than an FOP.

Experimental 33RP #2 -- 7.5 degree, (I deliberately ground this more aggressively, just to see what will happen).

Here's the GB'd chain as measured with the calipers. I measured 3 of the scoring cutters and 3 of the regular cutters and took an average for each.

regular cutters -- 6.03 degree

scoring cutters -- 7.2 degree

The caliper results are just the opposite of the DAF results -- the DAF said the regular cutters were more aggressive, while the calipers said the scoring cutters are more aggressive. The DAF is wrong and the calipers are right, because I intentionally ground more off the scoring rakers.

I can only guess that the narrow shape of the scoring cutters throws off the DAF somehow.

Even though the calipers are more reliable, the DAF is faster and easier to use, so I'll stick with the DAF most of the time.
 
The first thing I learned is that it would be handy to have a "real" chain vise. I have been using an old bar to hold chains for measuring and filing, but the slight curvature of the bar throws off the DAF measurements. For now, I just put a mark on the bar, leveled the bar at the mark, and did all my measurements at the mark.
Yep I agree chain stability is a problem, but I found an even worse problem is not holding the DAF truly vertical, and such that the chain does not drop into the little magnetic dimples some DAFs have on their sides.

To get around this I use this.
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This consistently sets the horizontal depth at which the measurements are made and holds the DAF upright making it much easier to make the measurement. Here's a video of my setup and how I do it. http://www.youtube.com/watch?v=FSr9j2EDoqk

When holding the DAF like this the main holding force is against the wooden back and the DAF is bought down firmly to push the chain onto the bar so it much less likely to push the chain sideways

BTW zeroing the DAF to the bar is not really right since tzero line should be the line between two adjacent cutter tips. If one wants accurate results then one needs to rezero for every pair of cutters but then who cares about about having rakers set to +/- 0.001"?

The DAF is wrong and the calipers are right, because I intentionally ground more off the scoring rakers.
I can only guess that the narrow shape of the scoring cutters throws off the DAF somehow.
Even though the calipers are more reliable, the DAF is faster and easier to use, so I'll stick with the DAF most of the time.

I used calipers to measure the cutting angles on all my chains in a similar way you show for about 6 months so I have done thousands of measurements with calipers (and DAFs) and while they can be less precise I disagree that the DAF is less accurate. On examining the actual contact points involved with both setups, what I found was that it's using calipers that will give the incorrect angle.

Provided the DAF is held still vertically and the chain is held consistently, the DAF measures the angle directly onto the actual raker wood contact point like this blue line.
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The Caliper measures the raker height as per the red line which is not correct. To measure the distance between the cutter tip and and the contact point using a caliper is basically impossible. Cutters that have slightly differing hook or raker shape means that the required distance is not being measured right. Measuring the gullet is just an approximation - so while using a caliper will give very precise results but they are not necessarily measuring the real cutting angle.

In reality precision is what matters for an individual chain, ie being able to reproduce the angles that work for you on that one chain. If I can get the angle to between ~6 and 6.5º I consider that close enough for regular cutting (and a DAF is only good to about 0.2º anyway). However, accuracy is important if we want to be able to compare angles between different types of chains and to discuss angles on this forum. The best way to do this is using the most accurate method available.
 
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an even worse problem is not holding the DAF truly vertical
I deliberately tried rocking the DAF side to side, to see how sensitive it was, and it only changed the output a tenth or two.

Nonetheless, I admire your DAF jig, and will try to borrow some of your good ideas if I ever find time to make a chain vise.



The Caliper measures the raker height as per the red line which is not correct.
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That may be true if the raker is rounded, but my rakers are all ground (or filed, if I'm using an FOP) with a straight slope.

I set the grinder depth 1/8 turn deeper on the scoring rakers, so there is no doubt whatsoever that they are ground deeper. The calipers got it right, the DAF did not.

This is the GB'd chain. You can see that the rakers are not rounded. All cutters on this chain were all ground at the same angle and length. The only difference in cutters is the width, which you can't see from this angle.

I don't have an explanation at this point, just reporting what I observed.
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Here's the raw caliper data for the GB'd chain. It shows that all the cutters were all the same approximate height, but the scoring rakers were lower than the regular rakers.

type/# ... cutter height ....raker height....raker depth
score 1 .... 0.487" .... 0.446" .... 0.041"
score 2 .... 0.493" .... 0.437" .... 0.056"
score 3 .... 0.485" .... 0.444" .... 0.041"

cutter 1 .... 0.493" .... 0.451" .... 0.042"
cutter 2 .... 0.489" .... 0.454" .... 0.035"
cutter 3 .... 0.489" .... 0.454" .... 0.035"

The biggest source of error for the caliper technique is measuring the gullet width, because the caliper points are too skinny to contact the curves surfaces correctly. Some "eyeballing" was required.

No doubt my DAF accuracy will improve as I hone my technique. Thanks for your suggestions. :)
 
I just checked the DAF on a drafting triangle and the output was spot on.

I'm sure the error I'm seeing on chains is due to the uneven surfaces and short distances involved. Perhaps your suggested jig will help -- if I can ever find time to make it. :D
 
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