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Thread: Surprised, dissapointed, puzzeled

  1. #1
    Join Date
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    Surprised, dissapointed, puzzeled

    I made two dovetailed drawers today. Both have four tails/pins at each corner. The wood was straight grain (quarter sawn) fir. A softwood. I was trying out two new sets of chisels. Actually one chisel from each set. One is the Veritas PM-V11 at 1/2" the other is LN A-2 also at 1/2". Both sets are fairly new. The LNs I have had for about one year and have used frequently to cut dovetails in Walnut, Ash, and Cherry. No problems with the LNs. Normal dulling and touch-up sharpening. The Veritas PM-V11 is new and this is the first actual use, other than doodling around just to see how they behaved. Both chisels have a 30 deg bevel with an additional 2 deg micro-bevel. In other words the cutting edge is 32 deg. Both are sharpened to 8000 grit with a waterstone and then polished with Veritas green compound on a piece of MDF.

    When marking for the dovetail baselines (using a wheel gauge) I noted that the Summer wood rings (dark) were noticeably harder than the Spring wood rings (light). Hard enough that my wheel gauge did not want to score them. Basically the wheel edge rode over the dark rings and left little, if any, scoring. I did not pay much attention to this. Just noticed it.

    Cutting the dovetails to the marked lines was no problem. Then came the chopping out of the waste. This is when things became surprising. I did the first drawer with the LN A-2 chisel and the second drawer with the Veritas PM-V11 chisel. I just wanted to compare the edge retention of both. What a surprise. Half way through the first drawer the LN A-2 was looking very bad. The edge had failed badly. I could see and fingernail feel the ragged edge. It had notches in the edge, rounded over. Serious enough that I needed to go down to 1000 grit waterstone to clean it up, and thence to the 8000 grit and green rouge polish. When I finished the first drawer I again had the some ragged edge and had to redo the edge with 1000 grit followed by 8000 grit, then the green rouge polish. To say the least I was rather unhappy and puzzled about the poor performance of the LN A-2 chisel.

    I then started the second drawer using the Veritas PM-V11 chisel. Lo and behold, I had exactly the same results with the Veritas PM-V11 chisel. Halfway through the drawer and the edge was ragged, in the same way as the LN chisel, and I had to redo the edge. At the end of the second drawer the edge was equally bad as at the halfway point. In other words the edge retention seemed to be the same with both the LN A-2 and the Veritas PM-V11 with this wood.

    This was all a great surprise to me. Is the Summer wood (dark/hard) in qtr sawn fir really hard enough to cause this edge failure? Is something else at work here? I really don't know. Has anybody else experienced similar edge failures under similar conditions? Any ideas?

  2. #2
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    I recently chopped mortises in a walnut tabletop, walnut is typically a very easy wood to work. The particular section I was chopping into was heavily interlocked and was hard like stone.

    So, not everything is normal, you can hit sections of woods that are truly hellish to cut for what seems to be no reason at all.

    I do try to avoid damaging my tools when I hit stuff like this, so I will slow down and take smaller cuts, relieving the cut if need be.
    Bumbling forward into the unknown.

  3. #3
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    Hi David, I also have same problem with Dougfir.Its got to be the hard and soft layers that need two different bevels.Too steep and the soft wood crushes too low and the hard layers break the edge.
    I use Japaneese chisels but still need to be careful and take small cuts like Brian suggested.Aj

  4. #4
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    Douglas fir is a lot harder and more problematic than most people give it credit for. It's a 'softwood' categorically but as you've discovered the dark rings can be pretty darn hard. Around here it's the predominant tree. As such I get lots of chances to reclaim old growth douglas fir that was used for studs in old buildings. You can't drive nails into it without pilot holes.

  5. #5
    I am making two benchtops from tight grained Doug fir, it is tough on planes as well. Even pmv steel does not like those knots. I was lucky that I found more or less knot free 2x12s.

    One of the benches is Paul Sellers hybrid with apron that has a 8x6 inch 5/8 deep dados for legs and a wedge. Those dados took some effort to chop out, about an hour for first and 30min for the last. In Seller's video it looked easy in the pine he was using, not the case with this fir.

    I used Narex 1.25 inch chisel at 35 degrees, but ended up with 1 inch chisel at around 30 degrees because it seemed to work better. I refreshed the edge frequently. Steel was not chipping though. I do have a set of Veritas pmv chisels, but like narex better for banging out the big stuff. Maybe you just need to grind off a bit of steel that is brittle.

  6. #6
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    One of the peculiarites in this game seems to be just how close to the wind most steels run when used in blades, especially when used for chopping on chisels. Even in the fancier chisels. Just paring the wrong material can fairly quickly destroy an edge as i discovered recently when i unthinkingly used a chisel to clean up the routed rebates for some hinges in plywood. (the adhesive was probably the cause) It's only when you try the same job with a well sharpened box store chisel and see the edge fold over on first touch that it becomes clear how much better the good ones are.

    I guess the point in the end may be (?) that if a new steel that was twice as chip/folding/wear resistant as anything about now we'd just see bevel angles reduced to bring it right to the brink too - on the basis that the latter delivered an improvement in performance.

    Given that pressure = force/area it's actually a big ask that an edge that's probably a fraction of a micron thick is asked to handle being driven through hard wood. Thinking about the likely mechanics the chances are too that the only effect of increasing a bevel angle is to cause a shorter distance back from the edge to suffer damage, and to make it more resistant to folding. A sharp edge is still a sharp edge, the pressure must be enormous. Especially when its likely not cutting across the full worth of the blade, and the force is instead maybe concentrated on a short section resting on a hard growth ring, glue line or something......

  7. #7
    What is the bevel of the chisel? 25 or 30? 30 degrees is recommended as the edge is more durable for A2 and PM-V11.

    I have hit knots but not plow through it. Just constant and gentle strokes. The edge for PM-V11 is still good.

  8. #8
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    When I first started chopping tails I had the same issue. I found that my mallet blows were simply too hard. I eased up, and things went much more smoothly. Another mistake I made, was prying ever so slightly. I think this might have been doing more damage than the heavy mallet blows. Now, I can usually go through an entire boards worth of tails, and only need a quick touch up on my finish stone.
    Blood, sweat, and sawdust

  9. #9
    I was drilling some small holes in DF once and the bit kept skating off the dark (hard) growth and into the lighter softer growth. Overall I guess the wood is of medium hardness, but is comprised of growth that is half soft as marshmallow and half hard as rock.

  10. I built the stand for my work bench out of DF, and was chopping in the corners of big mortises (like 2"x2"), and the chisels had this happen all the time. I actually found that a cheap set of beater chisels with a convex bevel worked better than my other set of better chisels with a microbevel. It was rather eye opening just how difficult of a wood it can be.

  11. #11
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    Soft wood is a term that can be misleading. Douglas fir has rings that are very hard. I would refrain from using it myself,except to build houses.

  12. #12
    What you are reporting about the chisels is close to what others have said, the new steel is marginally better not a miracle
    like a Ron Popeil invention. Some woods are harder to cut and were used just because they were available and cheap.In the south a lot of tough pine was used for things that had dovetails.When the softer NE white pine started to be "imported"
    from the North many we're glad to pay more for it. It has always seemed to me that alternate soft,hard grain is
    worse to cut than all hard grain.

  13. #13
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    May 2011
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    I built my bench top from some reclaimed Douglas Fir 3x6 timbers that were approximately 40 years old. My impression was that they had become harder with age. There still was a difference between the rings, but harder even in the 'soft' rings. Does wood, at least Doug Fir, get harder with age.

  14. #14
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    Quote Originally Posted by Richard Line View Post
    I built my bench top from some reclaimed Douglas Fir 3x6 timbers that were approximately 40 years old. My impression was that they had become harder with age. There still was a difference between the rings, but harder even in the 'soft' rings. Does wood, at least Doug Fir, get harder with age.
    Yes, any wood with a high sap content gets harder with age. Southern Yellow Pine and Douglas Fir are especially well known for this.

    ************************************************** *

    For those curious to explore the density differences in DF, simply take a flat sawn piece and sand it with a fairly aggressive grit. You will get peaks and valleys between the growth rings, with the dark portions barely being scratched and the lighter portions being hollowed out. If you don't want to actually explore like that, but still get a sense of what happens, find a piece of DF ply and you can feel the elevation differences in the faces. That's with plywood that's been machine sanded using massive wide belts... The density difference is profound with DF.
    It came to pass...
    "Curiosity is the ultimate power tool." - Roy Underhill
    The road IS the destination.

  15. #15
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    Just my 2¢ Two Cents.jpg.

    My only experience with PM VII is the Preston copy spoke shave Lee Valley offered.

    My first experience was that the blade chipped a bit until it was sharpened a few times. Since then, it has held an edge quite well.

    On chopping dovetails in "softwoods" my use of a fret saw has improved to the point of not having to chop them out.

    The designation of being a softwood or hardwood has more to do with how the species produces flowers and seeds than it does with actual hardness of the wood produced by a particular species.

    This may explain it better for anyone who is interested:

    http://www.diffen.com/difference/Hardwood_vs_Softwood

    Alder is classified as a hard wood. It is softer than many of the woods classified as softwoods that have been used in my shop.

    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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