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Belt or Disc sanding hammer tapers

  • 1.  Belt or Disc sanding hammer tapers

    Posted 03-07-2018 08:39
    Edited by Jim Ialeggio 03-07-2018 08:40
    To adjust hammer weights to my targets, prior to hanging, I taper on a Spurlock type setup, using a good sharp Forrest table saw blade for the cuts. I like my system and its a real clean cut. However, occasionally, as taper adjustments get the biggest bang for weight changes, I want to go back to an already cut taper and remove more. A second machine/jig pass on an already tapered hammer difficult to do and set up, for a single hammer...so I don't re-taper, on my Spurlock type setup.

    The easy way to adjust an already tapered hammer, would be to take it to the stationary belt sander (6x48) and eyeball it. My problem with sanding this way, is that is stains and mucks up the felt. I have tried 50 grit blue alumina zirconia belts, 100 grit dark brown aluminum oxide. Both make a real mess of the hammer. The 100 grit is worse than the 50 grit, as it runs much hotter, I think.  How do those of you who use sanders for tapering avoid gumming up and staining the hammer side?

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 2.  RE: Belt or Disc sanding hammer tapers

    Posted 03-07-2018 08:54
    Edited by Jon Page 03-07-2018 09:14
    I use an oscillating spindle sander. The molding is held against the drum and does not touch the felt. The felt at the tapered ends can also be tweaked a bit to dress the taper a littler more. A small diameter sleeve with allow for removing from below the shank in front at the 'cove' area, an uncoved hammer will allow for more weight removal (.3 gram). You can also cove the portion of felt below the staple at the rear for about .1 gram.

    I pre-file, taper and weigh the hammers first. Removing the hammer where the underfelt goes halfway thru and remove too low or too high weight hammers.  I weigh the shank SWs. I match the hammer weight to the shank to target a curve. I do the final weigh off after hanging, trimming off shank protrusion and tail arcing.

    High SWs are dressed on the spindle sander. I have lead pre cut to lengths. Small pieces of wood of differing thicknesses are marked for their weight length. I think there is about 1.5~2 mm for each .1 gram difference. Having containers of these weights make bringing up the weight easy.
    I use modified shank removing pliers to swage the lead. As pictured, it is for a hole all the way thru. The piece of dowel acts as an anvil when placed on the top prong for shorter holes. The lower prong is a machine screw in an insert with the threads ground down.



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    Regards,

    Jon Page


  • 3.  RE: Belt or Disc sanding hammer tapers

    Posted 03-07-2018 10:18
    Jim,
    I've used the same method you describe and found using a vacuum helps, although not completely eliminating the wood stain; enough to my satisfaction though. Mahogany moldings are most noticeable. I use 80 grit. What I like about sanding is the fact you can be very precise.
    Roger





  • 4.  RE: Belt or Disc sanding hammer tapers

    Posted 03-07-2018 18:23
    Usually I'm not trying to take off all that much so I just tape a sheet of standard 50 or 80 grit garnet paper to the top of the bench and sand them by hand. Then I blow the residue off with an air gun.

    ddf

    --
    Delwin D Fandrich
    Fandrich Piano Company, Inc.
    Piano Design and Manufacturing Consulting Services -- Worldwide
    6939 Foothill Ct SW -- Olympia, WA 98512 -- USA
    Phone 360.515.0119 -- Mobile 360.388.6525





  • 5.  RE: Belt or Disc sanding hammer tapers

    Posted 03-08-2018 08:45
    I also use the spindle sander method.

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 6.  RE: Belt or Disc sanding hammer tapers

    Posted 03-08-2018 10:58
    I use the table saw method as well.  When I have a hammer where I need to take off more, even after it's been hung, I use a plane secured in a bench vise (see attachment).   Pull stroke sometimes works better than a push stroke.  When pushing I use a notched piece of wood or dowel to spare shaving off parts of my fingers.  But if the plane is sharp you can just drag it across while holding both in hour hands.  You can be very precise and shave off from either the felted area or the tail.  There won't be any staining.  The hammer molding does have a grain and usually it cuts better in one direction than the other.  You can do the whole set that way if you want.  Easier than sanding by hand, I think--and less messy.



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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 7.  RE: Belt or Disc sanding hammer tapers

    Posted 03-11-2018 23:10
    Bear in mind that in the area around the hammer bore, the molding can't get too thin, or you might not be able to break the glue joint and remove the head if you need to.

    ------------------------------
    William Ballard RPT
    WBPS
    Saxtons River VT
    802-869-9107

    "Our lives contain a thousand springs
    and dies if one be gone
    Strange that a harp of a thousand strings
    should keep in tune so long."
    ...........Dr. Watts, "The Continental Harmony,1774
    +++++++++++++++++++++
    ------------------------------



  • 8.  RE: Belt or Disc sanding hammer tapers

    Posted 03-12-2018 09:56
    Thus enter WNG shanks which are significantly smaller diameter than wood.

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 9.  RE: Belt or Disc sanding hammer tapers

    Posted 03-12-2018 11:23
    If you use the following multipliers on the speaking lengths to calculate the distance the hammers must be from a properly V-shaped V-bar, you won't have to worry about "correcting" your treble strike line.

    (note88  .064),  (note83  .075)  (note78  .085),  (note73  .089),  (note68  .094)

    I use a 20" disc sander to taper the sides with a vacuum cleaner attached to catch (some) of the dust. Very powerful, dangerous machine. One must have a most delicate touch and if you don't have it, I don't suggest the tool. 80 grit Aluminum oxide abrasive. If one uses minimal pressure against the disc, (which you should to be safe), even hammers with lacquer in them can come out clean looking. If your work piece begins to vibrate, LET GO OF IT BY PULLING YOUR HANDS BACK IMMEDIATELY. No loose clothing! No neck scarves!

    The old style tone regulators at Steinway had a two blocks to hold the hammer while planing. One block was for first side taper, the pother for second.

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    Edward McMorrow
    Edmonds WA
    425-299-3431
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  • 10.  RE: Belt or Disc sanding hammer tapers

    Posted 03-12-2018 23:43
    I use my DeWalt 12 inch compound miter chop saw.
    Turn the Spurlock jig around,, depending on your blade guard, I had to shorten the handle.
    Screw the jig to a flat piece of plywood. Fasten the board to the saw. I use a 72 tooth carbide blade. I took off my blade guard
    The cuts are clean. You can sight down the hammer and blade before you pull the trigger and the dust blows away from you. Table saws suck especially with the Weikert formula felt.

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    Keith Roberts
    owner
    Hathaway Pines CA
    209-728-2163
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  • 11.  RE: Belt or Disc sanding hammer tapers

    Posted 03-13-2018 09:07

    here's my "Spurlock style" jig. I didn't post it originally because it is specific to my shop's tooling. 1-1/4" heavy shaper, Forrest fine crosscut blade bored to 1-1/4". But the taper concept is Spurlock-like.  I think I uploaded these pics as attachments rather than imbedded in the text...we shall see.



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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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