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  1. #16
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    Hi Paul,

    The belts are 6" X 48". The tractor tires (tyres?) are 16" d. 16 X 3.1415926 = 50.xx so it's a bit of a squinch but with no pressure and a little patience it can be made to work. After the belts are seated a few PSI holds them nicely in place.

    The motor is a Baldor 1 h.p. TEFC 3 phase on a Teco VFD. The small pulley is ~1.75" and the larger is ~12", shaft is 3/4" X 36". One belt is 80 gr, the other 120 gr. At about 40% (~24 Hz?) on the VFD is just right for grinding. Lots of pyrophoric iron chips coming off, handle with extreme care...

    Regards,
    Rob
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

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  3. #17
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    Nov 2011
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    Quote Originally Posted by rob streeper View Post
    Hi Paul,

    The belts are 6" X 48". The tractor tires (tyres?) are 16" d. 16 X 3.1415926 = 50.xx so it's a bit of a squinch but with no pressure and a little patience it can be made to work. After the belts are seated a few PSI holds them nicely in place.

    The motor is a Baldor 1 h.p. TEFC 3 phase on a Teco VFD. The small pulley is ~1.75" and the larger is ~12", shaft is 3/4" X 36". One belt is 80 gr, the other 120 gr. At about 40% (~24 Hz?) on the VFD is just right for grinding. Lots of pyrophoric iron chips coming off, handle with extreme care...

    Regards,
    Rob
    Can we please keep the words manageable for Australia boguns please.

    Cheers Matt

  4. #18
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    Nov 2011
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    Melbourne
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    https://www.facebook.com/groups/8571...235892?sfns=st

    This just popped up in a Facebook group Im following.


    Cheers Matt.

  5. #19
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    Thanks Matt.

    IIRC Footprint (or maybe it was PAX?) saws had a video of grinding saw blades on their site some years back. I think they were doing them with either either a surface grinder or maybe a blanchard grinder.

    Regards,
    Rob
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  6. #20
    Join Date
    Dec 2015
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    Pudget Sound Washington,
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    I recently bought a metabo deburring grinder and did a few hand saws with it, took a bit of work, but the results were very nice.

  7. #21
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    Dec 2015
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    Pudget Sound Washington,
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    saw blade grinder 2.jpgThis has ingenuity
    written all over it, amazing! Nice work Rob.

  8. #22
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    Just found this.
    US Patent: 181,650 - Double Taper Saw Blade
    Looks like you need some rollers for your next upgrade.

  9. #23
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    Dec 2015
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    Pudget Sound Washington,
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    You would have to have some kind of wicked roller, I had wondered why I never see any grinding marks on Disstons. Cool find. I have a slip roller and to have it taper the blade without curving the metal would take some ingenuity.

  10. #24
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    Gavin

    Although Disston took out that patent I suspect they might not have used it to any great extent. The reason I say this is twofold. Firstly they make references to the taper "grinding" process and secondly the blades were not taper ground the same along their length which is what I would expect if they were rolled. This extract is from a Simonds publication, but I have seen the same for Disston too. I just can't remember where off the top of my head:

    Simonds taper grinding.png

    Added to that, in practice I have in the past measured the thickness of Disston saw blades and they reflect the picture above.

    Bearkat

    I think the absence of grinding marks may be more to do with yet another process, that of "polishing" which removed much of those marks. Having said that, as you go further down the range some of those marks do become evident.

    I have just found what I was looking for, a disston publication

    "How a Disston Handsaw is Made."

    It can be seen here if you subscribe to the International Tool Catalogue library.

    https://archive.org/details/HowADiss...IsMade/page/n3

    Registration is free, but these are the relevant pages. The publication was dated 1922:

    How a Disston Hand Saw Is Made _ Henry Disston & Sons, Inc. pp4, 5.jpg

    How a Disston Hand Saw Is Made _ Henry Disston & Sons, Inc. pp 6, 7.jpg

    All the references are to grinding rather than rolling.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  11. #25
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    Sheesh, and I just figured out how to make my saw teeth reasonably sharp. This is a amazing, and I love the ingenuity!

  12. #26
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    Great reference material, thank you for that.

  13. #27
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    Quote Originally Posted by hiroller View Post
    Just found this.
    US Patent: 181,650 - Double Taper Saw Blade
    Looks like you need some rollers for your next upgrade.
    IIRC there are some additional patents on roll tapering.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  14. #28
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    Paul,

    The actual taper is of a typical Disston blade is nothing like that diagram. The Acme 120's are similar with about 0.003" decrease in thickness in the first 0.5 cm or so. The taper is generally pretty linear going from tooth to back with the exception of the back edge where the degree of taper becomes abrupt.

    Regards,
    Rob
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  15. #29
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    I had always assumed that saws were taper ground so was surprised when I found the patent.
    He does sound pretty confident in the patent that rolling is far superior method.
    Guess it didn't work out as well as planned.

  16. #30
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    Quote Originally Posted by rob streeper View Post
    Paul,

    The actual taper is of a typical Disston blade is nothing like that diagram. The Acme 120's are similar with about 0.003" decrease in thickness in the first 0.5 cm or so. The taper is generally pretty linear going from tooth to back with the exception of the back edge where the degree of taper becomes abrupt.

    Regards,
    Rob
    Rob

    Are you sure about the tapering on Disston saws. Apologies that I have been slow in replying. I have a digital micrometer and the batteries had expired. I was unable to source them in out small town and was waiting for them in the post. I grabbed the closest Disston to hand, which was the "Kenyon" replica for which I had used a modified Disston No.12 saw plate. I took measurements at 4" intervals. The measurements at the toothline indicated a degree of sharpening as the blade did thin down a little towards the toe. This was to be expected as the No.12 was a much deeper saw when new. However, the back would not have changed and it was here that the taper was greatest at the toe gradually thickening towards the handle where it was nearly the same as the tooth line.



    The crossed out figures are where I had not realised the device had "locked" the figures. I must have pressed the wrong button. After the third one was the same and thicker than I was expecting I twigged

    I then checked two more No.12s, one D15 and two D-15s. Whilst the figures were not identical the general pattern was the same, except the tooth lines were a consistent thickness. I believe this points to grinding unless the rolls were reversible so more rolling could be achieved at the toe. The consistency makes this doubtful to my mind. Having said that, I think that amongst all the trades within saw making the grinders might have been the most highly paid possibly indicating a level of difficulty and skill.

    In case the pic is difficult to read the tooth line goes from .036" at the heel to .028" (should be .036" the whole way) at the toe and the back tapers from .034" at the handle to .021" at the toe.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

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