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Thread: How hard are cast iron plane soles?

  1. #1

    How hard are cast iron plane soles?

    I have a couple of long planes in my rehab queue that look like they'll need some sole flattening, and I'd like to try scraping. Does anyone have a ballpark for Rockwell hardness for Stanley plane soles? I'm trying to avoid buying new tools to rehab old tools, and I have some HRC ~50 scrapers that I'm hoping might work.

  2. #2
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    Quote Originally Posted by Tyler Bancroft View Post
    I have a couple of long planes in my rehab queue that look like they'll need some sole flattening, and I'd like to try scraping. Does anyone have a ballpark for Rockwell hardness for Stanley plane soles? I'm trying to avoid buying new tools to rehab old tools, and I have some HRC ~50 scrapers that I'm hoping might work.
    According to MatWeb, grey cast iron (which is what Stanley used for their plane castings) has a Brinnell hardness of less than 235, which would put it somewhere around HRC 23 or under. If you try using a scraper, what's the worst that could happen? It might work, or you might just need to re-sharpen your scraper.

  3. #3
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    If I recall correctly Scott Wynn describes using the blunt end of a file to scrape the bottom of a plane in his book
    "Getting Started with Handplanes: How to Choose, Set Up, and Use Planes for Fantastic Results".

    I'd confirm it, but can't seem to find my copy.
    Last edited by Mike Soaper; 10-16-2021 at 10:27 PM.
    Hobbyist woodworker
    Maryland

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    Someone posted about using tools with a 90 bevel on them to use like a one tooth float in plane making.

    It worked so well on a beater half inch chisel that an eighth inch and quarter inch chisel were also made into 90 bevel chisels.

    Here is rust being removed from a block plane using the half inch 90 bevel chisel:

    a Scraping Rust w:90 Chisel.jpg

    The blunt end of a file will have even harder steel than a chisel. If it has a sharp corner is should work quite well.

    It might be prudent to check for burrs. If the file blank was stamped it may be necessary to use a stone on the file to prevent scratches.

    Hmmm, maybe that is something to do with an old worn file sometime to try.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  5. #5
    I've used the end of a file for scraping a plane before, and will agree on what Jim said about scratches,
    and I've used a cheap wide chisel with much nicer results, i.e blunt chisel method, but at the same time being way too aggressive
    in terms of leaving tracks from the edges which can get very deep, so equally not as good.
    I didn't create any camber like on an actual scraper, as I was skewing the chisel to scrape over the mouth without dropping into it.
    David Weaver commented before about actual scrapers having a tendency to cause issues with the mouth chipping.
    So I think that rules all out those methods to be happy with personally.

    I think I might just try a bit of his method, but not go to town either, well I'd likely be checking more often than David is in the video.
    He posted a youtube recently about it, and I have a thinner flexible file now so it would work better than what I had at the time.
    Hope that helps,

    Tom
    https://youtu.be/s7d3MFgItFI

  6. #6
    I have watched machine repairmen res-crape machine ways when re-building machines and i am here to tell you that there is quit an art to it. And to get really good at it , it takes a lot of training from a person how has a lot of experience at it and a lot of practice. My advise is leave it alone. If you are asking questions about it on a forum , the plane will be in better shape if you forget about scraping.

    Yes I know that every old plane needs to be re-flattened when it is purchased. I personally do not know why but that is what everyone thinks. And everyone knows how to do it and that it doesn't take very long. As a lot of you know I used to regrind planes and I can tell you it took about 2 1/2 hours to regrind a #4, with a machine built to do only one thing and that is to surface grind metal. I do know that I when someone sent me one to straighten out after they ( who knew all about how to do it) screwed it up , that they were right or left handed. And it usually took over 3 hours on the grinder to regrind the plane.

    You will be better off using a wire brush mounted on a bench grinder to wire brush the bottom and sides. The bottom so all the rust and everything is cleaned up and the sides so that it looks nice. (A clean car drives better). Not much has happened to the body right from the manufacturer to now so wax the bottom and use it. The key to any hand plane, wood or metal, is a sharp blade and that is where you want to concentrate your effort, not on the body.
    Tom

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    I have a couple of long planes in my rehab queue that look like they'll need some sole flattening, and I'd like to try scraping.
    Tyler, what indication do you have of "they'll need some sole flattening"?

    If your long planes can take a shaving in the 0.002-0.004" range, that isn't so bad as to need correction. Yes, they can be tuned to take a much finer shaving, but that can be left for the short planes called smoothers.

    Tom B. makes a good point. Most people are more likely to mess up the geometry of a plane than they are to make it better.

    My suggestion is to make sure there is a problem before trying to correct it.

    My sole flattening set up was cobbled together using a four foot hunk of granite:

    Granite on Horse.jpg

    It has been used more for flattening the backs on rust hunt chisels than correcting the soles on planes. For me, the plane has to prove it needs work on the sole, other than removing rust, before the sole is abraded. Then a plan of attack has to be formed to correct a specific problem

    Most people trying to lap the sole think just run it back and forth a bit and all will be fine. That is a very wrong way of looking at the task. The swarf will build up in the center and needs to be removed every few passes. The sole of the plane also needs to be checked every few passes.

    One example if the sole of the plane is convex (has a belly) simply going back and forth may make it worse.

    Another example is if the plane is concave if it is pressed in the center of the bowed area it will likely just make the sole thinner.

    The cast iron of a plane body is fairly soft compared to sandpaper. It cuts fast.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  8. #8
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    I gave up trying to flatten the soles of old planes long ago. That doesn't mean that some didn't need it; but I work wood, not metal; so I didn't bother with the ones that were doubtful.. I had a nice collection of old Stanleys that worked quite well with nothing more than a cleanup on a deburring wheel. Like Tom said above, the chances of achieving a flat bottom on a foot-long plane, using sandpaper and a flat surface, is a reach. In fact you might ruin the plane in your efforts.

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