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Thread: Chipbreaker for hard woods

  1. #1
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    Chipbreaker for hard woods

    I keep my chipbreaker about 1 mm back from the blade edge, and on woods like oak and cherry it works fine. While planing ipe I noticed fine chips/sawdust accumulating just in front of the chipbreaker (NOT between chipbreaker and blade). Generally, plane was generating sawdust, not shavings and was noticably harder to push. So I moved it back to maybe 2 mm, and all of a sudden, I was making full-length shavings and the force needed to push the plane dropped drastically. Went back to white oak for a check, and the difference wasn't nearly as pronounced.
    So, are there some guidelines for setting chipbreakers wrt wood type? FWIW, Ipe is harder and more crack-prone (stiffer???) than oak. (Shavings are much easier to break than oak ones.)
    The plane is a Record #4 with a PMV11 blade (and original Record chipbreaker, ground down and polished to close any gap w/ the blade). Blade is honed to 8000 and works just fine on white oak.

  2. #2
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    So, are there some guidelines for setting chipbreakers wrt wood type?
    The only guidelines to my knowledge is to go with your experience and if something isn't working, make an adjustment.

    FWIW, Ipe is harder and more crack-prone (stiffer???) than oak.
    This is was likely the cause of your extra resistance and the creation of "generating sawdust" instead of a continuous shaving. If it were a softer wood it would still have the resistance but make 'accordion' shavings which are also an indication the chip breaker is too close to the cutting edge.

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

  3. #3
    Fine chips and dust accumulating at front of c/b suggest that the front edge of c/b is not in good shape.

    Roughness of any kind, or a trace of square edge will produce this.

    I notice that few chipbreaker edges are correct from the manufacturer.

    What we want is a 45 degree sharp, polished edge. ( Angle can be steeper.)

    best wishes,
    David

  4. #4
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    At 1mm back from the edge, the chipbreaker is unlikely to be affecting the cut. At 2mm, it is definitely out of the game.

    For most if my local West Australian hardwoods, I would set the chipbreaker around 0.3 - 0.4mm from the edge for smoothing cuts. As David points out, the leading edge of the chipbreaker requires careful preparation. I tend to add a 50 degree secondary bevel to LV and LN chipbreakers. Stanley chipbreakers can remain as is. The underside if the chipbreaker become critical when so close to the edge. I must be flat and mate cleanly with the blade.

    Regards from Perth

    Derek

  5. #5
    Sounds to me like a function of sharpness.

  6. #6
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    I'm with Robert Josko. I would have maybe never thought of moving the cap iron when first encountering a dust at the chip breaker and/or more effort to push the plane issue. I would immediately pull the iron for a sharpening session.
    David

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    The active area of my chip breakers are usually polished on a fine stone. This is followed by an application of the wax du jour.

    Resistance encountered when planing is caused by a combination of forces. A tight mouth can hinder a shaving's exit and increase resistance. This can be relieved by opening the mouth or backing up the chip breaker.

    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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    Quote Originally Posted by Derek Cohen View Post
    At 1mm back from the edge, the chipbreaker is unlikely to be affecting the cut. At 2mm, it is definitely out of the game.

    For most if my local West Australian hardwoods, I would set the chipbreaker around 0.3 - 0.4mm from the edge for smoothing cuts. As David points out, the leading edge of the chipbreaker requires careful preparation. I tend to add a 50 degree secondary bevel to LV and LN chipbreakers. Stanley chipbreakers can remain as is. The underside if the chipbreaker become critical when so close to the edge. I must be flat and mate cleanly with the blade.

    Regards from Perth

    Derek
    So I measured the standoff (with a feeler gauge and a vertical blade on a horiz. reference surface) and I get .4 mm in the 'normal position, and 1.1 mm in the pullback position. Guess I eyeballed it a bit too roughly earlier.

    Also checked the angle of my chipbreaker, and it's pretty close to 70 deg right where it meets the blade. I'd been concentrating on polishing the inside so no light shows, and pretty much neglected the outside surface. Maybe it's time to get an LV chipbreaker and see if it makes a difference.

  9. #9
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    I'd been concentrating on polishing the inside so no light shows, and pretty much neglected the outside surface.
    All it needs is a check to make sure there isn't a burr to impede shavings. Give it a few strokes on a stropp and it should be good to go.

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

  10. #10
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    The record #4 needs the forward edge of the throat opening filed at an angle; if it is left square to the sole, it will choke up when you move the chip breaker close to the cutting edge, and have a small throat opening.
    Filing it at an angle gives you a lot of room for shaving clearance.
    Chip breakers can be ground and shaped, with a microbevel on the end. This also gives you more chip clearance. The micro bevel is what does the work, the rest of the chipbreaker, just supports it.
    The microbevel on the chipbreaker is a stop, that the rising shaving hits into and puts backpressure on shaving, preventing it from tearing ahead of the blade cutting edge.
    Experiment with the distance of setback from the blade edge, relative to shaving thickness, there is a sweet spot for each shaving thickness and wood type. Its a balance of relationship.
    put the chipbreaker as close as you can, try it, then move it back a bit, try it, rinse and repeat for various shaving thicknesses and you will get a good understanding of how it works.

  11. #11
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    Sounds like the mouth opening is too tight after you fitted that thicker replacement iron.
    Last edited by Stewie Simpson; 02-27-2020 at 10:12 PM.

  12. #12
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    The optimal chipbreaker setting varies with depth of cut, leading angle of the chipbreaker, and the properties of the wood being planed. 70 degrees is fairly steep but close to what was used in the famous Japanese article from years back. It can be effective but I think steeper angles are more sensitive- less margin between not far enough and too close. I prepare mine with a ~50 degree edge and a rounded bevel.

    Beyond that, though, don't set the chipbreaker any closer than it has to be. If you didn't get any tear out when you pulled the breaker back then that setting is fine.

    Depth of cut plays a big role as well. Your initial setting may have been fine with a lighter shaving. The optimal CB setting distance increases as the shaving thickens, all else equal.

  13. #13
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    Quote Originally Posted by Josko Catipovic View Post
    So I measured the standoff (with a feeler gauge and a vertical blade on a horiz. reference surface) and I get .4 mm in the 'normal position, and 1.1 mm in the pullback position. Guess I eyeballed it a bit too roughly earlier.

    Also checked the angle of my chipbreaker, and it's pretty close to 70 deg right where it meets the blade. I'd been concentrating on polishing the inside so no light shows, and pretty much neglected the outside surface. Maybe it's time to get an LV chipbreaker and see if it makes a difference.
    Josko, if the chipbreaker had been set back 1-2mm, as you mentioned earlier, it would have little impact on the cutting of the blade. I assume that the blade is sharp. I have taken this as a given, since you have mentioned that only certain woods are involved in creating dust. Your updated information reveals that the chipbreaker is closed up appropriately, as is the angle at the leading edge of the chipbreaker (higher than I would use, but what this really does in actuality is offer a little more freedom to move it further back from the edge).

    Dynamics change now with the chipbreaker closed up. The size of the mouth becomes an issue. As other have mentioned, your result sounds like the mouth is too tight ... to tight to permit shavings to flow through as the chipbreaker is blocking the escapement. The "dust" is likely to be a symptom of the shavings not being able to form and escape. A similar symptom is when the shavings become excessively crinkly (like a concertina). Mark suggested filing the back of the mouth to ease the process. I know that David has written about this in his books. This may work. The easier way is simply to open the mouth by sliding back the frog. With a closed up chipbreaker, a wider mouth size does not impact negatively on tearout. So, simply open the mouth. (Note, this is about the chipbreaker/escapement relationship, and not due to a thicker blade, per se. However, a thicker blade will aid this process if one does not take into account that it closes up the mouth).

    Regards from Perth

    Derek

  14. #14
    Quote Originally Posted by Robert Hazelwood View Post
    The optimal chipbreaker setting varies with depth of cut, leading angle of the chipbreaker, and the properties of the wood being planed. 70 degrees is fairly steep but close to what was used in the famous Japanese article from years back. It can be effective but I think steeper angles are more sensitive- less margin between not far enough and too close. I prepare mine with a ~50 degree edge and a rounded bevel.

    Beyond that, though, don't set the chipbreaker any closer than it has to be. If you didn't get any tear out when you pulled the breaker back then that setting is fine.

    Depth of cut plays a big role as well. Your initial setting may have been fine with a lighter shaving. The optimal CB setting distance increases as the shaving thickens, all else equal.
    Yes, we use a rounded bevel on the cap iron. We have used this configuration since the 18th century. I have used a rounded bevel with 80 degrees at the point where it meets the plane iron since 1976. And as Robert mentions, the setting of the cap iron depends not only on the quality of the timber, but the thickness of the shaving. A cap iron that is too close will leave a surface that will be cloudy like a scraper or a high angle plane.

    I would not buy a Lee Valley cap iron. It was designed by people who had no idea how to use a double iron plane. Your Record cap iron is fully capable of fine work.
    I would sooner try the original Record plane iron instead of the PM VII.

  15. #15
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    Warren, there is nothing wrong with the LV chipbreaker, although I modify them. I certainly prefer them to both the vintage Stanley and Record chipbreakers (which can flex too much, which is an issue when setting them close to the edge of the blade) and also the two-piece Clifton chipbreakers (which are not rigid enough). The earlier Record two-piece chipbreakers, which the Clifton were modelled upon, however, are more rigid. Still not my preference. More modern Record planes have a chipbreaker similar to LN and LV.

    What I do to prepare the LV and LN chipbreakers (and one can do with a modern Record) is to add a little bend to create a little spring, and then round the leading edge at 50 degrees. Now this creates an excellent chipbreaker.

    I would not recommend changing out the PM-V11 steel. It is about the best modern steel available for planes and chisels. The powdered metal allows for a very fine and also consistent grain. You also do not know what steel is in the original Record plane - it may be a later model which uses tungsten! Now that would be even worse than A2!

    Regards from Perth

    Derek

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