Bandsaw blade question.......

Discussion in 'Woodturning Discussion Forum' started by odie, Dec 10, 2012.

  1. MichaelMouse

    MichaelMouse

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    Three-wheelers are another beast. They don't bend the blades double, so even though the wheels are smaller, won't have as much hardening effect. The big throat is the reason they still exist. Patternmakers used them a lot, but most every pure woodworking shop featured the 20-24" double wheel saw when I was a pup. Three-wheelers didn't resaw, but they could make patterns for molds of pretty good size, as long as they were no more than 4 inches thick.
     
  2. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I think that some of the DoALL bandsaws where I worked might have been three wheelers because some had 36 inch throats and if I am not mistaken others had 48 inch throats. They were real behemoths.

    BTW, when it comes to work hardening from flexing, it does not matter how far around a wheel a blade wraps if the contact distance is enough to flex a gullet to the curvature of the wheel. Determining that angle is not quite as easy as it appears because aerodynamic pressure makes the blade tend to float at one end and stick at the other.
     
  3. odie

    odie

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    Decided to order one 3/8" and one 1/2" alternate set, 3tpi, carbon steel blades from carbide.com.....and did that yesterday. If a bi-metal blade had been available in this configuration from this supplier, I probably would have gotten one of those, too......

    Thanks for all the input here......it forced me to learn something I didn't know. This is the real reason I participate on this forum.....self improvement. I suspect there are a few here who are not of the same frame of mind.

    I've used the 3/8" positive claw Timberwolf blade probably a dozen times since having any trouble, and it's been cutting smoothly and quickly......as it should. Since it's only been a couple of weeks since it was removed from the packaging, and is new and sharp.....those who keep suggesting I'm using a dull blade should take note of these things. I checked back on the bowl blank that was giving me so much trouble, and see that it was 26 percent MC, so that probably needs to be factored into the equation. I believe everything since then has been in the 18-22 percent MC range. The troublesome bowl block was sold to me as Goncalo Alves, but I've got suspicions that it's not......but, it could be. Grain looks similar, but I've done quite a few Goncalo Alves in the past, and it's not quite the same.

    Note: It is per my usual procedure, to take bowl blanks that aren't completely flat on the bottom surface, to make a flat surface on the 6x48 belt. Occasionally I have to use wedges on very large blanks, to have a stable platform for bandsawing. Anyway, the troublesome bowl blank was flat, and not subject to tipping while being cut........best I can figure, is it had to do with the positive claw configuration, in combination with moisture content, and species.....(and, the species is questionable for positive identification.)

    ooc
     
    Last edited: Dec 13, 2012
  4. Edward Weber

    Edward Weber

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    Odie , don't take this the wrong way but your comment,
    "Since it's only been a couple of weeks since it was removed from the packaging, and is new and sharp.....those who keep suggesting I'm using a dull blade should take note of these things."
    makes little sense to me, since I find it to be out of context.
    I don't know what or how much you cut in a couple weeks and a BS blade can be dulled in an instant. Just as everyone seems to have their own definition of sharp, they also have their own definition of dull.
    I hope you have good luck with your new blades.
     
  5. robo hippy

    robo hippy

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    I have found wet black walnut to be the worst thing for my bandsaw blades, It might be the high acid contend. They just go dull a lot faster when cutting it.

    robo hippy
     
  6. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I was about to say the same thing, so thanks for saying it for me and possible others as well. Odie, I think if you view this from the perspective of those offering help that the rest of us do not have your advantage of actually seeing and using the blade nor do we fully know the extent of your knowledge and experience with bandsaw blades. As a result, we are to some extent, shooting in the dark and hoping that some of the shots hit the target.

    Now that I have said that, I and others did spend some time and effort earnestly offering what we thought might be of help. It is obvious that not everything offered is dead on target, but so what? Weren't all suggestions genuine offers of help? Time to dismount from your high horse.

    I am sure that everything mentioned was useful to somebody reading the forum. There are lurkers, you know. Maybe they don't participate because some of the regulars, including your's truly may be a little curt from time to time. I'll try to wag a more civil tongue (starting with my next post) -- and when I forget, you and other need to remind me.
     
  7. Bill Boehme

    Bill Boehme Administrator Staff Member

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    There is not much black walnut around here, but I discovered a couple years ago that sometime it can dull tools almost instantly. Alan Lacer was at our club for a week of hands on classes and one of the things we were doing was using a skew to turn some green black walnut. It was giving everybody in the class fits. Alan said to me, "Your skew isn't sharp", so he sharpened it. Next, he said, "You must be using the skew wrong", followed a bit later by, "Let me show you", followed by, "there is something wrong with the steel in your skew", followed by, "I'll show you with my skew", followed by, "what the heck is going on here .... ?" The problem was the black walnut. One of the guys in the class had access to a scanning electron microscope in the lab where he worked and what he saw looked like sandpaper -- large crystals of silica. He brought some photomicrographs to the class the next day to confirm the silica problem.

    Well my project was a tool handle for a Thompson bowl gouge and I was not going to let that little bump in the road deter me. After the class was done, I decided if you can fight fire with fire then why not fight sandpaper with sandpaper. That's what I did and that's why sandpaper is a turning tool. :D

    By the way, the tool handle looks pretty good and nobody would know how it was turned unless I told them.
     
    Last edited: Dec 13, 2012
  8. odie

    odie

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    No "high horse", Bill.........what about the dozen, or so bowl blanks I've cut since the problem bowl blank? You did understand that the blade has cut well before and after the problem bowl blank, didn't you? Those cut fine and smoothly, as I said before. All I'm saying is the band saw blade is sharp......if you are disputing that, well, I don't know what to say, other than the blade is only a couple weeks old, and cutting like a sharp blade......you can take my word for it.....or not.

    Let's take it from there, and just assume my band saw blade is sharp. There are other factors that are subject to discussion, and/or speculation.

    At this point, I'm feeling confident that the problem is the tooth configuration of the 1/2" blade I was using, and the current 3/8" blade I am using, in conjunction with the species and moisture content. I have some new blades on the way with alternate set. If I have the same problem with those, I'll be sure to restart this thread and open it up for discussion. Thanks to some independent internet searches, and links you posted, I did learn something, and I thank you for that.

    ooc
     
  9. Edward Weber

    Edward Weber

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    I'm glad you learned more information about bandsaw blades, but the main point Bill and myself are trying to make is, don't admonish people who are genuinely trying to help with a question you posted.
     
  10. odie

    odie

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    Ed......I think you and Bill are reading something into what I said.......:D

    .....and, thank you for trying to help.

    All I was trying to point out is the blade is sharp. I've been using a personal band saw for much longer than the 30 years I've been turning bowls on a lathe, and I may have had something to learn about tooth configurations of band saw blades......but, I know when it's cutting well enough to call it sharp.

    ooc
     
    Last edited: Dec 15, 2012
  11. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I am glad that you received some useful information from the thread.

    I'll just take a cue from Forrest Gump and end with, "that's all I have to say about that".
     
  12. Bart Garber

    Bart Garber

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    Can anybody here tell me the difference of bi metal and carbon blade in terms of performance.
    Sorry . I didn't mean to hi jack this post.
    Thanks in advance.
     
  13. robo hippy

    robo hippy

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    It would be about the same difference as there is between carbon steel turning tools, and the high speed steel turning tools. They hold a good sharp working edge a LOT longer.

    robo hippy
     
  14. MichaelMouse

    MichaelMouse

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    Bi-metal blades have HSS alloy tips on a flexible back. Not quite like carbide tips, which are also available, but ahead of induction-hardened teeth on standard blades.

    For fresh wood, even if you wash it, I think you'll find it's the grit in the bark which dulls. The alloy will be scored just as rapidly as the carbon with the dirt, though it's more resistant to heat and wear, which makes it dandy for dry and clean work. Excellent for metals.
     
  15. Bill Boehme

    Bill Boehme Administrator Staff Member

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    It is surprising how much silica some wood contains. Black walnut may be among the worst, but white oak is up there too. When you get a piece that is especially high in silica, it can dull a blade rather quickly.
     
  16. MichaelMouse

    MichaelMouse

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    Since I took to WD40ing the blade after use with those acid woods, blades have lasted longer. Corrosion is a player.
     
  17. robo hippy

    robo hippy

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    Well, I don't do much oak, but have been through a lot of walnut. It really does dull the blades and turning tools faster than most other woods. I always figured it was because the wood has a higher acidic level than other woods. Not sure about the silica though. I did have a board of Ipe, and if you laid it out in the sun, it would glitter.

    robo hippy
     
  18. Bill Boehme

    Bill Boehme Administrator Staff Member

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    MM and Robo,

    Did either of you happen to see my Alan Lacer v. black walnut post?

    If I can find out who made the photo micrograph, I might be able to obtain a copy if it is digital and post it here. It was really interesting. I'm sure that Alan still remembers that experience.
     
  19. MichaelMouse

    MichaelMouse

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    Saw it, but since I have not experienced what he claims, I let it go as hearsay.
     
  20. Bill Boehme

    Bill Boehme Administrator Staff Member

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    OK, but Alan, I, and five others were there in the class at the shop of one of our club members. Beyond that there is not much "evidence". Alan was as sceptical as you are about silica until the classmate used the SEM where he works to get the images that showed a huge amount of silica. My piece of the black walnut is now a handle for a bowl gouge and I am not willing to surrender it to the advancement of science by destructive analysis to confirm or discredit my wild haired claim. Several years ago I turned one other piece of black walnut in a swap with someone from up "Nawth" on Sawmill Creek. I sent him a piece of mesquite in return. I don't know if it could be something like the alkaline soil here that was responsible for the difference, but that first piece of Yankee walnut turned without any problems that I recall.
     

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