Lost Set

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Lost Set

Postby sumnergeo » January 28th, 2018, 7:03 pm

On getting the Simonds No. 133 ready for an outing in April I found that the set on about half of the 48 cutters were off, mostly underset. This is a 5 1/2 foot saw.

Since I'm careful when I set teeth, in this case hammer set, I know that the original set was .008. I found the set on the under set teeth was .004 to .006 so it was quick work to reset them.

We had used this saw for a week in April 2017 and cut about 20 trees ranging from 10 to 23 inches and either Douglas Fir or yellow pine. I'll assume that by using the saw, the repeated to and fro effectively "unset" some of the teeth. I had a note on the saw to resharpen it before the next outing so there must have been something about how the saw was working that made me want to check it.
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Re: Lost Set

Postby PATCsawyer » January 29th, 2018, 6:25 am

Did you back hone the teeth before setting them? If not, the burr from your final point up will overhang the back edge of the tooth tip by several thousandths of an inch. That burr will quickly wear off in use, leaving you with underset teeth. See if your saw now keeps its set after it's second setting.
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Re: Lost Set

Postby Jim_Thode » January 29th, 2018, 9:02 am

PATCsawyer's idea that three may have been a little bur on the teeth makes sense. Another maybe less likely possibility is that maybe the teeth are really soft and the set wore off. Only cutting 20 logs should not wear down the teeth, the saw should be good for couple hundred logs before any sharpening in needed. Were the logs bone dry? Dry wood will wear a saw more then green wood.

In use the teeth are not flexed in any way that would reduce the set and steel does not creep or relax over time.

What kind of set measuring device was used? Spiders can give an wrong indication if the saw is flexed or if the surface is not smooth and clean.

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Re: Lost Set

Postby Jim_Thode » January 29th, 2018, 9:27 am

Another thought, most filers would set the teeth on that saw closer to 0.012" for trail work. If the saw was used for cutting only dry, hard, unstressed wood the 0.008" or even less would be fine but you never know what you'll find on a trail.
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Re: Lost Set

Postby sumnergeo » January 29th, 2018, 11:33 am

I don't recall checking for a burr when I set the teeth. Good tip. I use a spider. I also forgot about another outing when we cut out 17 loblolly pine logs, 18 to 26 inches in diameter.

As to the set, I try to keep something close to what the saw had originally. One reason for doing is is that when I first started sharpening saws I managed to break a couple teeth. Since then, I've gone with a minimalist (?) approach. If most of the teeth are .012, that is what I go for. This saw had most teeth at .008 and it runs well with minimal bind in the cuts.

With the updated log count, it would be around 40 logs and each typically has two cuts and most all the wood is dry. Trees were in the Arizona mountains and Texas forests, so mostly conifers but several hardwoods in the east Texas woods.
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Re: Lost Set

Postby PATCsawyer » January 29th, 2018, 2:38 pm

Below is how a burr folds over a tooth when filing. I file my cutters with a two step process. First I profile all the teeth, bringing them close to a final point, but leaving a small flat dot. Next I'll hone the burr off the back side of the tooth being careful not to hone past the dot, usually a few soft strokes with a fine diamond hone. Then I'll hammer the set, finish the rakers and lastly file to a sharp point. During final point up I scuff off any new burr with a piece of hardwood, as anything abrasive would change the set.

Burr on right
Burr on tooth tip.jpg


Backhoned teeth showing reflection of flat smooth metal. If the saw is clean steel like this one, you don't need to remove much metal. If pitted, you'll want to file it back more and this would be done in an earlier step.
fullsizeoutput_1279.jpeg
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Re: Lost Set

Postby sumnergeo » January 30th, 2018, 7:44 am

Good idea to post the honing-setting-filing steps again.

In summary, I do things pretty much this way although I back hone with a) light pass of a file on the side of a jointer b) block of hard arkansas or c) 320 grit wrapped around a block of hardwood (I don't have a diamond hone!). I also maintain the tiny diamond on the top of the cutters until the final touch up filing.

I suspect my culprit is the spider and the way I use it. I'm going to go back over several saws to see how consistent I was in setting them. I checked two Simond No. 324s in my shop and they are fine.
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Re: Lost Set

Postby Jim_Thode » January 30th, 2018, 9:03 am

An option for cleaning up after the file is a fine EZE-Lap Economy Diamond hone. They are inexpensive and also can be used for an emergency touch up in the field.
s-l96.jpg
s-l96.jpg (2.06 KiB) Viewed 1647 times


A more consistent method to measure the set is a dial indicating gauge.
http://www.pbase.com/jimthode/dialsetgauge

Jim
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Re: Lost Set

Postby sumnergeo » February 4th, 2018, 12:09 pm

I went back and checked the set on another of my favorite saws. This one is a 4 ft Keystone #2, a D-handle. It is flat ground so I give it a larger set, 0.014 inches. This saw is one that I use for both solo and double bucking on smaller stuff (under 18 inches). The set for the first foot from the handle was as expected, .014 inches, spot on; but the cutters on the three feet out to the toe were underset! Again, I am pretty careful when I sharpen/tune a saw so have come up with a possible explanation.

This saw and the Simonds No. 133 are ones that I've used most recently. I put fire hose sheaths on both of them and then place them flat on the cargo bed. Since trail work also involves camping and or backpacking, I put a couple bins with food, gear and my pack on top and away we go. The bins are moderately heavy and perhaps bouncing up and down on the drive to a trailhead is enough to slightly unset the teeth. I have some plastic U-channel stock and will try that as a guard to protect the teeth (and possibly prevent unsetting the teeth) on the next outting in a couple months.
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Re: Lost Set

Postby PATCsawyer » February 4th, 2018, 1:37 pm

How close to the cutter tip are you hammering your set? If you make a sharp kink high on the tooth, it will weaken the metal and probably wear down sooner. I much prefer to hammer a slight overset -- just a thousandth or two -- lower on the cutter and backhone to exact set. This is quickly and easily done with the hone Jim mentioned, though an Arkansas stone should work if that's what you have. It also provides a more gradual bend in the tooth.

+1 on the channel lattice for a blade guard. The only thing I use firehose for these days is axe sheaths and swing blade covers.
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