Stanley side rebate plane No. 79 blades sharpening

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  • #728011
    Antonio Santos
    Participant

    Hello guys,

    I bought a second hand Stanley side rebate plane No. 79, and followed the method Paul Sellers describes in this article for sharpening the blades: https://paulsellers.com/2021/08/a-plane-difference/

    It seems to me that the plane is in very good condition and everything works fine.
    The blades were already sharpened (although not too sharp) from the seller, and it turns out that when I placed them slightly protruding the sole face, and abraded them on the diamond plate with the finest grain, I could see that the angle formed was very far from what it should be, seeing the shine on the new abraded metal.

    This seems to be a very big difference, and it doesn’t feel right, as neither the blade can’t even extend that far to see the full bed angle.

    Any suggestions what I might be doing wrong?
    Does anyone have a planer of this type?

    You can see from the photos the brightest part on the blades represents the part that was abraded into the diamond stone.

    Thanks in advance.

    #728025
    Alan Solyntjes
    Participant

    I am no expert – i’ve never seen this plane. However, I think that you abraded the back side, which should be flat, instead of the angled side.

    #729466
    YrHenSaer
    Participant

    You have a very good plane there, except that the design of this type of side rebate depends on the skew angles of the blade and the bevel angle on the other side being exact….. there’s not much leeway, it’s one of these things that you get exactly right at the start, then maintain it through its useful life.

    The previous owner may not have realised this; hence the angles are way out of line when compared to the sole.

    These blades are a fiddle to sharpen, I can’t deny that, but it is worth it when the plane is set up.

    Anyway, looking at the grind marks on the backs of the blades, the good news is that firstly, the dud angles are fixable (albeit with some patient work). You will need to continue to establish the grind line on the back to a point where it reaches both sides – this will give you the new skew angle, co-planar to the body of the plane, to which you need to abrade and adjust the bevel on the other side. Then, turn it over and wear a new bevel edge to meet it right across. At this point, having refined the cutting edge, you have a plane blade that is in-line with the body of the plane.

    If the other blade is in the same state, you’ll need to repeat the operation.

    Alternately, as far as I’m aware, spare blades are still available….. but even with new ones, you may need to do a little fettling to get the skews to suit your particular plane body exactly.

    I hope that this makes sense…..Good luck

    #729532
    Larry Geib
    Participant

    I agree the blade looks salvageable with some careful reshaping,

    But if you determine you need a new blade, the first place I’d try is Lie Nielsen. The side rabbet plane is the first tool that started the company, and reproductions were first made by sand casting one of the originals, so the blades should fit just fine. But just to be sure, I’d talk to the sales team to make sure before I plunked down my $40 for one.

    #729634
    Antonio Santos
    Participant

    @YrHenSaer, That’s what I was trying to do, because it seems to be the only possible solution to have the plane fully functional

    But then I noticed that as the slope is accentuated, the tip of the blades comes out of the plane, which does not make it functional.
    If the tips of the blades do not come out of the planer, they will not make a full width cut.

    And the other issue is that the two extremities of the plane do not let the blades come out completely, because they make a different angle. The solution would be to unscrew them and also file the inner area of these ends, forming an angle similar to the angle formed by the blades, so that the blades have more space to slide

    But then there’s the issue where the tips of the blades come off the plane… 🙁

    I don’t understand how this plane has been used in this way for so many years
    Because if the blades are not sharpened parallel to the sole of the plane, only the top of the blade will cuts not the entire width of the blade.

    I’m sending some pictures, I hope it helps to understand the issue.

    I drew some arrows to try to better explain the problem of the inclination where the blades are placed. The direction of the arrow represents the direction of the slope, from the smallest to the largest slope.

    #729639
    Antonio Santos
    Participant

    More pictures.

    #729678
    Ken Kilby
    Participant

    Those bevels you have circled are on the wrong side of the blade. You need to sharpen the other side back until they are gone.

    #729681
    Ken Kilby
    Participant

    I just looked at Mr. Sellers article on this plane and I see where you may be confused. He abraded the back of the iron like you did to mark the proper angle with no intention of leaving that bevel in place.

    #729683
    YrHenSaer
    Participant

    Hello Antonio, Apologies for the delay…… we’ve had an extended power-cut in this part of the world. No juice – no internet!

    I’ve just had a look at my version of that plane, which I bought new about 30 years ago….. it’s not in use every day, though works well. These things never work straight out of the box and always needs a little fettling – in my case, it was a long time ago, but just needed a decent edge put on the blades.

    From your photos,
    1 – The marks on the inner blade-beds are nothing to worry about. Mine has almost the same grind marks – plated over. I would strongly urge against widening the beds to compensate for a skew-angle problem further down.

    2 – However, the blade should slide freely in its bed – I estimate that the sideways slack on mine is less than 0.25mm… so don’t worry about that either. Don’t widen the sides of the blade bed at all.

    3 – I have checked the skew angle on my blades – it is 60 degrees, though there may be a tiny amount of latitude to suit the actual bedding seat in the plane block. The cutting angle of the bevels is very shallow – about 15- 20 degrees. The skew angles on yours are a long way out from that and there lies your problem.

    4 – When everything is set up to cut correctly, with the correct skew on the blades and the correct amount of protrusion, the pointed tips are intended to stick out below the bottom line of the bed…… if they finish above the level of the base line, the blades would not cut correctly. On mine the protrusion is about 1 mm below on each blade. The mouth opening is about 2 mm.

    May I suggest that you deal with one problem at a time. I think that the main issue is to get those blades right. Grind the skews at 60 degrees, next, as the bevels on the other side will be almost destroyed, re-establish those cutting bevels, sharpen the lot, back and front, and take it from there. If you then re-mount your blades, you – you may find a small pointed protrusion below the bottom edge of the plane – that’s quite normal.

    I think that your plane will work.

    good luck

    #729780
    Antonio Santos
    Participant

    @Ken, yes, you’re right and that’s what I did.
    Once I’ve done that, I’ve detected the problems I’ve already mentioned.

    #729786
    Antonio Santos
    Participant

    Hi @YrHenSaer, thanks for your inputs.

    Regarding your points:

    3 – One blade is 55º, the other is 53º, with the new angle formed. When I received them, one was 59º and 57º.
    The cutting angle has the normal angle that chisels have, between 25-30º

    4 – Ok, so that’s what I have to aim for. But If the pointed tips protrude 1mm. wouldn’t they leave a fine trace in the bottom of the groove, when they make the final pass?
    For that to happen, I think I have to also grind the tip of the blades, and that’s unusual, I think (picture in attach).

    I don’t think I can grind the skews based on an angle (in this case, 60º), because if I do that, I’m ignoring the parallelism between the blades and the sole of the plane. I have to grind it base on the method that Paul teaches, right?

    I think it’ll be dificult to have the blades sharpened parallel to the sole of the plane, without having to grind the planes mouths, to give some space for the blades to slightly protrude, parallel to the sole

    Começo a pensar que tenho mesma uma faulty unit 🙁

    #729794
    YrHenSaer
    Participant

    Unless Stanley made your plane differently, the correct skew is 60 degrees. Perhaps you could double check another 79 plane, if you can locate one. I’m sure that if you configure the skew angles and bevels on both your blades correctly, it will work. Sadly, your plane’s previous owner made a mess of the blades and his mistake is hanging you up.

    Grinding a skew at 60 degrees and then re-making the cutting bevel is not difficult if you have Diamond stones or a grinding wheel. This will get you back to what the blades should be.
    You may experiment with some stiff card, cut to the exact size and shape of the blade and shaped at 60 degrees. Put it in the plane and then see how it fits and how much protrudes.

    Yes, the tip of each one needs to protrude below the base-line of the plane – if it didn’t and the tip were above the base line of the plane, it would not cut beyond a couple of shavings then hang up.

    This plane is primarily intended to shave the sides of grooves or trenches – if the base of the groove is not seen, the mark made by the tip is not important. If you do not want this mark to be seen, position the fence height carefully so that the tip of the blade sits exactly at the bottom of the cut. That is what I do.

    This Stanley No 79 is the only Side Rebate plane with a full-length fence that allows you to do that reliably.

    The method that Paul Sellers shows is simply to align the blade’s skew angle to the alignment of the plane by scraping the back along a flat stone to establish a level if it is very slightly out of alignment. If it isn’t you can skip this bit. It is what I mentioned I did when I bought mine from new.

    But first you have to get the blade shapes right. Until you do that you are wasting your time on imaginary angles and bits sticking out.

    Good luck.

    #729897
    Antonio Santos
    Participant

    @YrHenSaer
    You may be right, I could be spiraling and confusing myself even more.
    I cut a piece of card with the same dimensions as the blade, with an angle of 60º, and with this angle it is perfect on the planer.
    My question is whether the back of the blade protrudes enough for the blade to actually cut.

    I don’t have a grinding whell, only diamond stones, but I think I will file the tips of the blades, to be quicker.

    But since at the moment the angles of the blades are not aligned with the planer, shouldn’t I use the Paul Sellers method to correct and find the correct angle?
    And why is the bed where the blades sit in an angle, and not parallel to the sole of the plane…? This way, only one side of the blade will cut, and not the full width, right (pic in attach)

    #730040
    Benoît Van Noten
    Participant

    “why is the bed where the blades sit in an angle, and not parallel to the sole of the plane…? This way, only one side of the blade will cut, and not the full width, right (pic in attach)”
    Indeed, looking at your various pictures, it seems the bed of the blades are not correctly milled which causes what you get when trying the Paul Sellers method
    (picture number ending with 153531 and 153540). The top of the blades being lower are abraded first.
    Try a string of paper (tape?) shim on the low side to see what happens.

    #730046
    Larry Geib
    Participant

    The blades fir the Stanley 79 should be ground with a 30° skew angle and a 25° Bevel.

    Without the proper skew angle the blade won’t project evenly beyond the side bed of the plane.
    The 7° bed angle doesn’t allow for much deviation from the proper skew angle.

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