Is the steel of my plane iron bad?

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  • #137941
    fasaxc
    Participant

    Sometimes, the iron of my plane iron seems to chip away when sharpening rather than taking an edge. I must’ve spent half an hour on my coarse stone but only part of the edge forms a burr, the centre area seems to crumble instead (I must’ve ground away about a millimetre of steel). I switched from hand sharpening to using a guide in case it was my technique but I still get the same result.

    Has anyone had anything similar? Can you think of any mistakes I might have made to damage the edge? Is it worth trying to grind away a lot of steel or will it be bad all the way through?

Viewing 8 replies - 1 through 8 (of 8 total)
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  • #137942
    Richard Senior
    Participant

    @sanhozay

    What are you using as a coarse stone? Is the stone clean and lubricated?

    Is it possible that the iron was ground on a wheel at some point and got way too hot?

    #137944
    fasaxc
    Participant

    @fasaxc

    I’m using an EZE-LAP coarse diamond stone with glass cleaner for lubrication. I wipe off the stone if I feel any bumps.

    It’s an ebay purchase so anything is possible. It didn’t have a concave bevel when I bought it though so that suggests it wasn’t ground on a wheel.

    #137946
    Alien8
    Participant

    @alien8

    If the steel crumbles even when cold sharpening, there is something wrong.
    You might try to re harden the steel and temper it again.

    that might be the only way to get it proper again. There are some video’s available on you tube, even master Paul has one. Either in the masterclasses section or YT.
    Never done it myself, but it isn’t too hard. Just don’t get any burns !

    Short of that, you’d be better off with a new iron….

    HTH
    Diego

    #137948
    Salko Safic
    Participant

    @salko

    Either it is bad steel or needs tempering, usually if it is bad as sometimes can be the case in irons grinding away a mm is sufficient but if it needs tempering which I’m more inclined to think that is your problem then temper it or buy a new iron. If the the steel is O1 then the tempering has only been done a 1/2″ to 3/4″ from the tip as all blades of old have been done but if it’s a modern A2 steel then the entire steel has been hardened and will not need tempering however then I would say it is only bad steel that needs to be grinded away, just be careful though you don’t take the temper out of it.

    https://journeymansjournel.wordpress.com
    The Lost Scrolls of HANDWORK
    (Hand tool only woodworking magazine)

    #137953
    fasaxc
    Participant

    @fasaxc

    Thanks for the responses. Think I’m going to buy a new iron and experiment with tempering this one. If that works, I’ll have a spare iron for scrubbing, which would be good anyway. Either way, I should learn something.

    #138232
    lukedupont
    Participant

    @lukedupont

    One thing not mentioned:

    What angle, roughly, are you sharpening at? I mean, you’re probably using a convex bevel I guess, but what angle near the edge?

    I have heard that all steel is prone to failing if you go much under 25 degrees, but this is especially true of hard modern steels such as A1. I sharpen with a slight convex bevel that ends at about 30 degrees at the edge. Occasionally, I go shallower, and have had a chisel sharpened at such a low angle fracture badly when mortising. It could be that the very hard steel combined with a low sharpening angle is the culprit. Try sharpening at 30-35 degrees near the edge before giving up on that particular iron.

    Alternatively, it could just be that your steel is too hard. A lot of modern plane irons are made with very hard steel compared to vintage planes, and are prone to chipping as a result. I have a vintage stanley plane, and the iron has never chipped on me; it’s gotten dinged up when hitting very hard knots, but never chipped or fractured.

    • This reply was modified 2 years, 8 months ago by lukedupont.
    • This reply was modified 2 years, 8 months ago by lukedupont.
    #138250
    fasaxc
    Participant

    @fasaxc

    I think I’m at 30 degrees. I actually tried tempering the steel. Seems to have stopped it from crumbling but I think maybe I went too far and made the steel too soft. I’ve been ill this week so I haven’t had chance to give it a proper try though. I also bought a new iron on the assumption that I’d need up the tempering so I’ll be able to compare that once I get back to it.

    #138549
    fasaxc
    Participant

    @fasaxc

    OK, I finished initialising and sharpening up the replacement blade (a RI021S from Ray Iles). The difference is night and day. The new blade sharpened easily and quickly, took a razor edge, and, now it’s sharp, it’s leaving a glass-smooth finish on the wood 🙂

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