Hard lesson on fractured teeth. Simonds No. 13

[MNSHIELD]

I am about 10 hours into this saw. I really wanted to slow down and work on getting it right.

I bought this saw from an antique shop in northern MN a few years ago. It was rusty but cleaned up well and was almost full length teeth and almost not set.. The original filer filed a third slope of the face of the tooth, and filed the rakers with a bastard file and left deep groves in the adjoining raker to the one he was fililing. The same groves showed up on the sides of the teeth also. Besides those things the original filing did not look to bad.

I got the rakers filed and set with out any issues, and was thinking I had this saw on the run. After I pointed up the starter teeth I noticed what looked like a fracture in the tooth like in the pics that I have seen on here. I stopped and set that tooth to .010 and to my surprise it held up. I continued to the next tooth and it also was fractured. This time during the point up the tip just fell off! haha. I then quickly proceeded down the saw and filed up one side of the teeth until I could see the fractures. I would guess about 80 of the teeth on that side were fractured.. I pointed up one more tooth and it to fell off!

Back on the wall!

[PATCsawyer]

Tough break(s). Looks like the previous filer may have kinked the teeth high at the tip. Simonds 13? The rest of the saw looks good so you could make a project out of it and joint down below all the fractures and start over. Start with a coarse file and hog off the metal down below the lowest fracture and do the same when reprofiling the teeth. Switch over to a smoother file once you have the teeth close to their final shape. There's a lot of life left in that saw once you resurrect it.

[Jim_Thode]

I have a Simonds 503 that is very hard and had several cracked tips when I got it. In order to set the teeth I had an option of softening (tempering) the cutters or finding some other way to set the teeth. I opted to set the whole tooth and not risk setting just the end of the tooth. That worked well and I was able to set all the cutters without breaking a tooth. The teeth are still very hard and hold a cutting edge very well.

The full story on this saw at: http://www.jimthode.net/Tech%20tips/sha ... ioning.htm

[MNSHIELD]

Thanks for the suggestions. I have not given up on it, just back on the wall to think about it! It will take a lot of jointing to get it back in line.

I do like the method of setting the whole tooth and have tried your example on a very pitted saw. worked really well and took the stress off of knocking week points off!

[MNSHIELD]

Hopefully all things DONT happen in 3's.

I just picked up a 5.5' simonds #133 with 1 5/8" long teeth. good shape. Can still see the red on the ends.

Having learned my lesson I quickly filed a few teeth in the center of the saw and sure enough more fractures! I filed up 4 teeth and all showed fractures in the tips. At least I know about it now, before I put in all the time on the rakers. Looks like I will have to joint off about 1/8" +-. other than that the saw looks really good.

Do you guys find a lot of fractured teeth?

[PATCsawyer]

On occasion. Some saws seem more prone to it. I've seen it a lot on Simonds 325s.

[Starling_Saw]

I see it more in almost new saws, where the factory sets the tooth, too close to the end or tip of tooth. setting a tooth where the fulcrum point is 1/4" to 5/16" from tip is better. I find also where the break will be at the fulcrum point, if the anvil has to sharp of a corner. A more rounded fulcrum point has less stress with less likely it to break. If only a single tooth from a kinked tooth brakeage, I'll forge a small amount of HSS and mild steel mixed onto tip of tooth. You have to protect adjoining teeth from heat from weld and from re-tempering the tooth that is repaired. You could also MIG weld a whole tooth in it's place by making the weld closer to the base of the tooth near gullet. Using a piece of copper to weld on and also small pieces used as heat sink to protect other adjoining teeth. All steel near weld needs to be pre-heated 200-250 degrees before attempting weld or there will be chill cracks develop along the marriage line of weld.
John

[sumnergeo]

I have a several No. 13s and a No. 113 and one of the 13s has the tips of three teeth broken off. They are not all together and it doesn't seem to affect how well the saw runs. I worried about it for a good while: joint the whole saw? (that would take a lot of time and I would have to reshape every tooth, gum out every gullet and reshape every raker); weld on a quarter inch of steel? (beyond my ability); do nothing? (lets me go into a long story about why there are three teeth with the tips missing).

This may be too anecdotal, but I find that Disstons are relatively easy to set and swage and that Simonds are much tougher to set and to swage.

One solution I've tried is to make the teeth thinner overall. For the rakers, a 30 degree tooth is easier to move than a 40 or 45 degree tooth. For the cutters, increasing the bevel from 45 degrees to 60 degrees reduces the overall thickness so there is less steel to move when setting. I've been working on a Simonds No. 324 and increased the bevel from 45 to 60 degrees (photo below), the angle for the tip of the tooth is about the same. I also tried to thin the tooth so that the angle at the tip is less than 45 degrees.

I nominally hammer set at about 1/4 inch below the tip but not in only one spot at the edge of my anvil. if 1/4 inch is about 6mm, I put the tooth at 6.4, 6.2. 6, 5.8 with several taps at each spot rather than ten taps all at 6mm. On lance teeth I may also go down 1/2" and 3/4" to get the teeth to move.

[Colorado Joe]

MY SCIENCE FAIR EXPERIMENT:

The volunteer trails organization that I associate with recently did a saw inventory. There were two orphaned 5’ perforated lance saws that didn’t make the cut – so to speak – and indeed I can’t say I’ve ever seen them go out. Both are more of a falling width, but are heavy enough that I think they would make good trail bucking tools.

One (saw A) was expertly filed and did not appear to have any cutting done with it after sharpening, but it had two cutters broken about 1/3 the way down the teeth. Despite the exquisite file job there was zero set on any teeth.
The second (saw B) was filed pretty well, but needed some work. It also, had zero set.

I asked for and obtained stewardship of said saws and had permission to do what might make them usable.

Saw A:
Thinking that the two broken cutters were due to setting attempts, I expected it to be a hard saw. The teeth were clean enough that I was able to inspect for fractures – I did not find any. Having read and re-read the posts in this thread I first tried Mr. Thodes’ suggestion of flat filing a tooth to clean it up and thin it. About 10 whacks and the tooth broke at the base of where the original filing began.

I next tried his method of placing the saw on a shim and hammering towards the bottom of the tooth (even made a tool like he said). Four, five good whacks and the tooth had still not moved an iota. A few more whacks and the tooth broke halfway between the hammering point suggested by Mr. Thode and the tip. To me this implied that the steel was hard AND brittle.

Next was heat treating. I was worried about softening the tips too much so I used his “spuds on the tips heat sink” and a propane torch to heat the tooth. I went for the first dull red because that was the first color my old eyes could see. I began by heating near the base of the tooth before moving to the tip. As soon as I saw the color I removed the heat.
I was able to put 0.012 in. of set on all the teeth with a reasonable amount of strikes. There are now four broken cutters but not more than one per cutter group. It still may cut well, we’ll see when the weather gets warmer and the snow melts. If it doesn’t cut well then I can cut it down to make a nice 42 inch one person.

WHILE SETTING THE TEETH, TWICE A BIT OF STEEL SPALLED OFF THE FILED FACE. It spalled out about half way down the filed face and did not reach to the edge on either side. As if it was jaggedly scooped out. Sorry, I don’t have a camera good enough to show it. Thinking about it, I surmised that perhaps the surfaces got tempered, but left a bit of hard, brittle steel in the middle that "popped out" when stressed by the setting blows. Might this be what happened to the raker that "crumbled" after heat treating that Mr.Thode mentioned in an earlier post on this thread?

Saw B:
I tried to set the first cutter on one end. After 43 strikes the tooth broke, confirming it was darned hard and perhaps brittle also.

I went straight to heat treating like Saw A, with the exception of when the dull read appeared I backed off then tried to hold that color for a count of five. I did not make any attempts to protect the teeth tips other than not applying direct heat, just letting it “seep” up there.

All the teeth set to 0.012 in. without incident, a slight swedging of the rakers went without incident. All teeth still were fairly hard to file so I think there will not be too much softness. I actually have high hopes for this saw.

Unknowns: Obviously the composition of the steel of each saw and any previous treatment for hardening them. “First dull red” is not much of a control for temperature, but I wasn’t willing to buy and experiment with any of the temperature sensitive paints.

My thoughts: If a person is reasonably careful to not get the saw too danged hot, but still allow time for the entire area being heated to reach equilibrium, then an old saw with good steel that is too hard to work with can be treated so that a good workability is achieved without sacrificing too much durability.

The End. Your thoughts?

[Starling_Saw]

When tempering the saw teeth, If you go to first Dull red, tooth will show a dull red in a low lighted room. That temperature is about 650 degrees. Which will be plenty soft to file or set. If you go to a bright red, it will be over 800 degrees and could be brittle when it cools. Always let the saw tooth cool with normal air. If it chills from a breeze from fan or wind blowing, it will be brittle hard. Which will result in breakage again. They don't need to be quenched in anyway! When I re-temper cutter teeth, I do use Tempilaq Temperature Paint. If you don't have it, you can look for the oxidized color of the steel to determine the temp it was heated to. Polish the steel bright and bring to a dark cobalt blue and it will be at around 550 degrees. You wouldn't see any red color on tooth at this temp. Most saws are Tempered at 450 in the factory and air cooled. When tempering cutter teeth, I also heat from the opposite side of the paint, or if no paint, I still heat from backside, as I want to see the color of the steel without any flame covering the visible color as it heats. When I move onto the next tooth, I will protect the previous tooth with a small piece of brass or steel, so the heat from the torch doesn't change the tooth I just re-tempered.