Jonathan McCullough
04-04-2010, 3:22 PM
Submitted for your possible entertainment and edification, a little saw restoration I’ve been doing in my journeyman sawyer’s odyssey.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky1.jpg
You may recall I picked up a $3 Disston D-95 “Masterpiece” with Disstonite handle. I’m thinking this saw shall be named Pinkie, because part of the plastic handle is a hideous pink fleshtone, born of that terrible mid-century kitsch you still see now and then. From afar, it kind of looks like a Barbie Doll that the dog dug up out of the garden.
I cleaned the plate up with a scraper, some mineral spirits, and some sandpaper, and it came out pretty well, considering. I like to sand some of the black corrosion off with fine, dry sandpaper. Though it may be considered heresy in some circles, I use a wire wheel to get the corrosion and wood tar/sap off of the tooth area. I’m just not going to be wrapping sandpaper on a wooden toothpick to finesse 260 teeth on one side, then 260 teeth the other.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky2.jpg
Now for a mini discussion on corrosion. As far as I can tell, there are three common types of corrosion on high carbon steel such as the spring steel used for saws. Black rust (Fe3O4) is a rust oxide much like anodizing is an oxide of aluminum. Though not as attractive as new shiny steel, it is protective and will not harm something like a saw. Red rust (Fe2O3) will put pits into the steel and ruin a saw. You see this type of rust on food cans that have been left out in the elements for years. Eventually the steel crumbles and breaks down. Another form of oxidation is brown rust, and you’ll see that kind of oxidation on things like man hole covers and some old guns. Apparently this is also a protective oxidation. At any rate, when cleaning a saw you want to get the red stuff out and clean any pitting out with a wire brush. You’ll never prevent oxygen or water vapor from touching the saw eventually, but I’ve been cleaning saws lately that were abused in my great grandfather’s lifetime that will probably outlive me and my son, so my advice is to just clean until the red and brown stuff is gone, and don’t sweat it if you can’t get the black stuff out. I like to finish the saw with 320 grit wet/dry sandpaper, without mineral spirits.
Now for the possibly more controversial part. After cleaning my saws as well as I can, I thoroughly rub paraffin into the surface, covering all, and I mean ALL of the surface with a fine thin haze of wax.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky3.jpg
I put an old sock on my hand, then I turn on the kitchen burner and slowly * s-l-o-w-l-y * warm the saw plate, about 18 to 24 inches above the flame, heel part first, until the wax starts to melt. Angle the plate so that the heat goes up, heats the plate, then goes away from your hand.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky4.jpg
Paraffin melts at about 150 degrees Fahrenheit, and after about twenty seconds, you can see it instantaneously change from a solid to a liquid state. When this happens, move the midsection of the saw over the flame, and the section of molten wax will spread.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky5.jpg
Move down to the toe until the whole thing is covered with glistening molten wax, then wipe it down with the sock on your hand. You want it to JUST get to the melting point of wax and no further. Don’t heat one end of the saw up and wait until all the wax is melted.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky6.jpg
It’s hot to the touch, a little too hot for comfort, as though the saw has been in the rear window of a car on a hot summer day. Ouch. But it cools rapidly. As it does, and you’re rubbing the hot wax with the sock, you’ll notice that the metal goes from an excited state to more of a spring steel state; as it cools, it starts to warble and sing.
I think that rust on a saw is like moss on a tuning fork. And this is rank speculation, but another thing that I think prevents a saw from singing after many years is the fact that if they’ve been out in the garage since 1953, or 1923, or 1873, they’ve been heated and cooled for decades. Twenty-degree-plus temperature swings, every day, for 120 years since the day it was tempered will (it is my conjecture) slowly but surely randomize the crystalline atomic structure of the metal. When you S-L-O-W-L-Y and CAREFULLY heat it up on the stove and it cools relatively rapidly in the presence of a cousin of mineral oil, the atoms realign.
Now this is not a procedure for thick-fingered bunglers, botchers, and clod-headed nincompoops. If you lay the saw on the range like a frying pan, fire it up and walk away, you’ll almost certainly draw out the temper and render the saw useless. Furthermore, I suppose the unwary and inept could catch the sock on fire and run around the house like Yosemite Sam with his ass on fire, looking for a hogshead of rainwater to sit in. So be careful.
Anyway, as it’s cooling, if your saw has a bow to it that you couldn’t flex out when it was cold, if you bend it in the opposite direction of the bend while it cools. Bend it about three quarters of the way, (all the way being from toe to heel) then sight down the teeth and the back to check alignment. If it’s perfectly straight, just let it cool. If it’s not there yet, keep bending it in the opposite direction until you’re there. You only have about 45 seconds to get this done. It will not take an “S” kink out; I'm working on a procedure for effecting that and will report later.
The wax has interesting optical qualities and gives the saw a sort of brilliantine finish. All of the little micropores are now clogged, so it prevents oxygen, water, and acidic wood sap from getting in there. And paraffin is something you should be rubbing on your saws anyway.
After sharpening, Pinkie turned out to be a pretty good saw. The taper grinding was a little more pronounced than a D-23, and with 10 tpi, Pinkie’s more of a fine finish saw. Pinkie has somewhat more refined sensibilities, you see.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky8.jpg
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky7.jpg
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky1.jpg
You may recall I picked up a $3 Disston D-95 “Masterpiece” with Disstonite handle. I’m thinking this saw shall be named Pinkie, because part of the plastic handle is a hideous pink fleshtone, born of that terrible mid-century kitsch you still see now and then. From afar, it kind of looks like a Barbie Doll that the dog dug up out of the garden.
I cleaned the plate up with a scraper, some mineral spirits, and some sandpaper, and it came out pretty well, considering. I like to sand some of the black corrosion off with fine, dry sandpaper. Though it may be considered heresy in some circles, I use a wire wheel to get the corrosion and wood tar/sap off of the tooth area. I’m just not going to be wrapping sandpaper on a wooden toothpick to finesse 260 teeth on one side, then 260 teeth the other.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky2.jpg
Now for a mini discussion on corrosion. As far as I can tell, there are three common types of corrosion on high carbon steel such as the spring steel used for saws. Black rust (Fe3O4) is a rust oxide much like anodizing is an oxide of aluminum. Though not as attractive as new shiny steel, it is protective and will not harm something like a saw. Red rust (Fe2O3) will put pits into the steel and ruin a saw. You see this type of rust on food cans that have been left out in the elements for years. Eventually the steel crumbles and breaks down. Another form of oxidation is brown rust, and you’ll see that kind of oxidation on things like man hole covers and some old guns. Apparently this is also a protective oxidation. At any rate, when cleaning a saw you want to get the red stuff out and clean any pitting out with a wire brush. You’ll never prevent oxygen or water vapor from touching the saw eventually, but I’ve been cleaning saws lately that were abused in my great grandfather’s lifetime that will probably outlive me and my son, so my advice is to just clean until the red and brown stuff is gone, and don’t sweat it if you can’t get the black stuff out. I like to finish the saw with 320 grit wet/dry sandpaper, without mineral spirits.
Now for the possibly more controversial part. After cleaning my saws as well as I can, I thoroughly rub paraffin into the surface, covering all, and I mean ALL of the surface with a fine thin haze of wax.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky3.jpg
I put an old sock on my hand, then I turn on the kitchen burner and slowly * s-l-o-w-l-y * warm the saw plate, about 18 to 24 inches above the flame, heel part first, until the wax starts to melt. Angle the plate so that the heat goes up, heats the plate, then goes away from your hand.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky4.jpg
Paraffin melts at about 150 degrees Fahrenheit, and after about twenty seconds, you can see it instantaneously change from a solid to a liquid state. When this happens, move the midsection of the saw over the flame, and the section of molten wax will spread.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky5.jpg
Move down to the toe until the whole thing is covered with glistening molten wax, then wipe it down with the sock on your hand. You want it to JUST get to the melting point of wax and no further. Don’t heat one end of the saw up and wait until all the wax is melted.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky6.jpg
It’s hot to the touch, a little too hot for comfort, as though the saw has been in the rear window of a car on a hot summer day. Ouch. But it cools rapidly. As it does, and you’re rubbing the hot wax with the sock, you’ll notice that the metal goes from an excited state to more of a spring steel state; as it cools, it starts to warble and sing.
I think that rust on a saw is like moss on a tuning fork. And this is rank speculation, but another thing that I think prevents a saw from singing after many years is the fact that if they’ve been out in the garage since 1953, or 1923, or 1873, they’ve been heated and cooled for decades. Twenty-degree-plus temperature swings, every day, for 120 years since the day it was tempered will (it is my conjecture) slowly but surely randomize the crystalline atomic structure of the metal. When you S-L-O-W-L-Y and CAREFULLY heat it up on the stove and it cools relatively rapidly in the presence of a cousin of mineral oil, the atoms realign.
Now this is not a procedure for thick-fingered bunglers, botchers, and clod-headed nincompoops. If you lay the saw on the range like a frying pan, fire it up and walk away, you’ll almost certainly draw out the temper and render the saw useless. Furthermore, I suppose the unwary and inept could catch the sock on fire and run around the house like Yosemite Sam with his ass on fire, looking for a hogshead of rainwater to sit in. So be careful.
Anyway, as it’s cooling, if your saw has a bow to it that you couldn’t flex out when it was cold, if you bend it in the opposite direction of the bend while it cools. Bend it about three quarters of the way, (all the way being from toe to heel) then sight down the teeth and the back to check alignment. If it’s perfectly straight, just let it cool. If it’s not there yet, keep bending it in the opposite direction until you’re there. You only have about 45 seconds to get this done. It will not take an “S” kink out; I'm working on a procedure for effecting that and will report later.
The wax has interesting optical qualities and gives the saw a sort of brilliantine finish. All of the little micropores are now clogged, so it prevents oxygen, water, and acidic wood sap from getting in there. And paraffin is something you should be rubbing on your saws anyway.
After sharpening, Pinkie turned out to be a pretty good saw. The taper grinding was a little more pronounced than a D-23, and with 10 tpi, Pinkie’s more of a fine finish saw. Pinkie has somewhat more refined sensibilities, you see.
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky8.jpg
http://i575.photobucket.com/albums/ss199/Jonathryn/Pinkie/Pinky7.jpg