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Thread: Cap iron fettling

  1. #1

    Cap iron fettling

    Having trouble with cap iron and looking for suggestions on my next step to address problem. I've gone through many threads on this topic and followed the recommendations for set up and correction. Here's the story: bought used coffin smoother. While setting up, I couldn't get the cap iron to sit tightly to the blade across the entire face. I found a slight rocking when I placed the cap iron on a flat surface and tapped on one corner. Looking at the cap iron straight on, I noticed that the hump on one side of the cap iron was larger than on the other. I put used small channel lock and a vise to gently and lightly "adjust" the flatter corner. Seemed to have worked well as the hump was uniform and went back and set up the cap iron again. No rocking on a flat surface when tapping on corners and visually cap iron sits nicely against back of blade. But still can't get proper shavings. I found two possible causes: 1) the cap iron rocks slightly on a flat surface when tapping on one of the back corners; 2) there is a slight deformation on the cap iron from the channel locks so that the curve is slightly flatter in one location. I suspect the first possible culprit is a red herring and the true cause is cause is the deformation from the channel locks., but I don't know how to address it. Any suggestions greatly appreciated.

    Eric

  2. #2
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    Hi Eric, this is where an image or two might help if you are able to post them.

    What is happening when you try to make a shaving?

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

  3. #3
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    Look closely where the cap iron meets the blade, the further most edge should touch first all the way along. If you have rocking as described I doubt it does. Careful grinding of the contact edge at an angle by moving it at 90 degrees to a stone with the cap iron drooping down on the bench or support can restore the correct contact with the blade. Once the contact is consistent choose a small gap and experiment with an easy wood.
    ​You can do a lot with very little! You can do a little more with a lot!

  4. #4
    Hi Jim - I'll take a picture and post. It scrapes some saw dust that clogs the mouth. Mouth is very tight but it seems as if the first point of dust impedance is dust collecting between the blade and cap iron.

  5. #5
    How close are you setting the cap iron?
    If the cap iron's set close enough for a half way influenced effect on the wood, you need to have an open mouth, otherwise
    there will be too much effort required to push the plane, and that could be causing other issues

    Depending on the thickness of the double iron, this could be a factor if your cap iron's flat, but the blade is not.
    You may need to give it a tap using a block of wood and a hammer.
    You might not be undercutting the cap iron enough for it to exert enough pressure on the very tip.

    If you can't get the cap iron to sit because there is a belly in the middle, use the corner of your stone when honing the underside,
    to create a slight hollow, after which you can use the whole stone to finish it off to flat.

    Another one which comes up often, is the primary ground bevel on your iron...
    Are you sure the heel is not rubbing and needs regrinding ?

  6. #6
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    Upon a second reading this has been pondered a bit deeper.

    [profoundly edited] Having trouble with cap iron... I've gone through many threads on this topic and followed the recommendations for set up and correction. ...bought used coffin smoother. ... the hump on one side of the cap iron was larger than on the other. ...used small channel lock and a vise to gently and lightly "adjust" the flatter corner. ... there is a slight deformation on the cap iron from the channel locks
    My recollection on my coffin smoothers is they do not have a hump on the cap iron. Is it possible you have a blade/cap iron combination the coffin smoother wasn't made to accept?

    When working on soft metals such as a cap iron, it is a good practice to use pieces of wood to insulate the metal from the jaws of vises and pliers to help avoid metal to metal deformations.

    If the shavings are jamming agains the cap iron, you may be able to shape the cap iron with sand paper on a hard flat surface.

    Getting dust is a common occurrence for many reasons. From my own work today after resawing some ash, the first few passes with a #6 produced dust with both a slightly dull blade and a sharp blade. By the third pass it was making shavings.

    If you cap iron is set back from the edge is the mouth still very tight? You may have a tapered blade that is too thick at the business end.

    Another possibility is the bed angle. Do you have a way of measuring the blade's bedding angle? A steep angle is more prone to dust making if the blade is dull.

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

  7. #7
    Here are a few photos. plane-5152_2_2000x.jpg This is essentially the same plane as I have but in much worse condition.
    Tom - I have sitting within 1/32 from the edge of the iron. The plane is essentially in original condition, produced by Alex Marshall. So the mouth is as it came from the maker, I suppose. I've flattened the back of the blade. I'll check but ground and honed the secondary bevel at 30 degrees. VYKTfvrSSM2lMV7L8RzvgQ.jpgrjOltVK6RkWiDr0nCkTzZQ.jpg2zQ3Iw02S5iYIJjhsJYGXQ.jpgh2hZJJ49QwS1cdtZZuWvsg.jpg

    Jim I believe this iron came with the plane. I bought it from Patrick Leach and the plane was untouched, still having a price sticker.
    Attached Images Attached Images

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    1/32 is not super close. It shouldn't be causing it to make dust instead of shavings, that sounds like a dull blade. But it could be that shavings are getting jammed against the wear before they can really form, so try pulling the chip breaker back to 1/8" or so and retesting. If the blade is sharp and you're still getting clogs, then start checking everything that might cause a wooden plane to clog. Make sure the wedge fingers do not protrude past the hump on the chipbreaker when assembled, make sure there is no debris or residue on the wear. Also, the bevel angle on the front of the chipbreaker is important, it shouldn't be much more than 50 degrees or so or the shavings will get deflected straight into the wear instead of up and out of the escapement.

    Try planing a narrow edge to isolate where specific trouble areas are. If still clogging and nothing else works, you can relive the angle on the wear a few degrees (i.e. make the wear more vertical) to give the shaving more room without opening the mouth. Lastly you can open the mouth a bit. With a double iron plane it doesn't need to be especially tight to prevent tearout, but I'd still like to keep it as small as I reasonably could.

  9. #9
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    I donít know if any of the photos are your plane based on your comment. The blade/cap iron fit in the pictures is very poor. There is a good contact point at one end only.
    ​You can do a lot with very little! You can do a little more with a lot!

  10. #10
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    If you have the cap iron off, to 1/8 or so, what happens? Can you get shavings, or do you still have problems?

  11. #11
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    +1 on what Robert, William and Nicholas said.

    The area where the cap iron meets the blade needs to be solid with no cracks, nooks or crannies for shavings to catch.

    An old post of mine has a little bit about fettling a cap iron:

    https://sawmillcreek.org/showthread.php?114373

    Post #27 & 28 are where the cap iron posts start. Much more has been learned since then.

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

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