Pianotech

  • 1.  Power Bridge Notcher

    Posted 04-19-2018 09:54
    I recently constructed a power bridge notcher for notching my laminated bridge caps. I know that Del Fandrich uses one of his own design and Ron Nossaman had used one that he had built. I've been notching the bridges on two Steinways that I have in my shop for belly jobs while tweaking the design of mine.

    Anyone else out there in PTG- Land use a power bridge notcher? Might be interesting to compare & contrast.

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 2.  RE: Power Bridge Notcher

    Posted 04-19-2018 10:25
    yup...I use one...built it about 4 years ago, or something like that.

    It takes power off the table saw. Bridge is mounted upside down, and you sight the notcher's kerf termination in a mirror. Works really fine, and aligning the piece is easy to sight and locate. From the pics it might be hard to understand how it works, the bridge being being upside down.  It is climb fed, as it must climb feed, or the notch sides will be torn out. Climb feed is dangerous. I mostly never climb feed by hand, as the cutter will grab the piece and pull it into the cutter, out of control...dangerous both to the piece and to the operator. So the sliding table, on linear bearings, is powered electronically, being cycled by a automotive power window actuator.

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 3.  RE: Power Bridge Notcher

    Posted 04-19-2018 10:36
    I should mention, that though I built mine to notch laminated bridges, I ditched the laminated bridges and have used really nice quartered stock instead for a while. Everything about the laminated bridge was such a pain in the ass, that I much prefer the solid cap at this point. I also had serious trouble with the epoxy lam lamination adhesion, so the added warranty exposure on top of other difficulties simply was not worth it  for me. I still use the notcher for the solid stock. 

    Instead, I'm real anal about bridge layout and minimized, consistent pin offsets. 

    Another reason I ditched the Lam caps is that I am not sold on Ron's analysis of the lam cap stability. I have a bunch of lam caps out there, and they are stable. But, I also have solid caps out there too, and they are stable too...I put my time instead into front segment bearing design, as I feel stability is enhanced by making the piano render in a tuner-friendly, transparent way.  

    I have pics of Ron's notcher, if anyone is interested

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 4.  RE: Power Bridge Notcher

    Registered Piano Technician
    Posted 04-19-2018 11:41
    I had adhesion problems with one epoxy laminated bridge cap and had to take it off the bridge. (Too much clamping pressure, it starved the joint).  Ron claimed that the epoxy saturated the laminations, but it was apparent to my eye where the glue line began and ended, and it was in the usual places.  I switched to Unibond 800, which I could tint lighter, making the glue lines almost invisible.  Less hassle and definitely less expensive than epoxy.  No failures so far.  

    Will Truitt

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    William Truitt
    Bridgewater NH
    603-744-2277
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  • 5.  RE: Power Bridge Notcher

    Posted 04-19-2018 11:50
    Hi Will.

    "I had adhesion problems with one epoxy laminated bridge cap and had to take it off the bridge. (Too much clamping pressure, it starved the joint)."

    Ouch! As I'm sure you have since learned, clamps for epoxy work are to hold pieces in position - not to apply pressure!

    "Ron claimed that the epoxy saturated the laminations, but it was apparent to my eye where the glue line began and ended, and it was in the usual places." 

    I agree. I am using slightly thicker laminations than he used, but like you, it is easy to see that it doesn't soak in very far at all. I've coated these last two soundboards with a very thin penetrating epoxy - I was thinking that I might try it on the next laminated caps I make.

    "I switched to Unibond 800, which I could tint lighter, making the glue lines almost invisible. Less hassle and definitely less expensive than epoxy. No failures so far."

    Hmmmmm. I sure can't pick out any fault with that right off. That Unibond cures REALLY hard! I have used the light tint with the Unibond previously with other applications, but using it on the bridge caps sounds like a really good application - great for cosmetics and likely just fine for any other consideration as well.

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 6.  RE: Power Bridge Notcher

    Posted 04-19-2018 11:42
    Hey Jim - thanks for the response. Nice looking notcher! I do understand the basics of what you've built. I like it! Good looking notches also.

    Jim wrote:
    "Climb feed is dangerous. I mostly never climb feed by hand, as the cutter will grab the piece and pull it into the cutter, out of control...dangerous both to the piece and to the operator."

    Boy did I find THAT out! Nothing disastrous, but I sure did experience the tendency of the cutter to want to rip into the bridge on it own. I ended up putting a couple springs to control the ability of my cutter to slide toward the bridge - I think I'm pretty close to having it optimized. Very easy to control now with no tendency to want to run away from me. Mine works the opposite of yours - bridge goes into notcher upwards and the motor and cutterhead are pushed (manually by hand) into the bridge to make the notch. And I use a pneumatic bladder operated with a foot control to clamp the bridge into position for the notch. Attached are a couple pictures. And please no comments on my welding - my piano work is MUCH better than my welding - I know it looks sloppy, but it works!

    The last picture (the one with the large side-mounted springs) and the movie are from yesterday. The first five pictures (no springs) are from some months ago when I first built it and before several recent modifications. (That is how it appears to me that the pictures will appear in my post - we'll see......)

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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     Video


  • 7.  RE: Power Bridge Notcher

    Posted 04-19-2018 13:09
    Terry,  What did you use for your cutterhead arbor/bearing setup. I had a machinist make mine, becasue nothing off the shelf would work..set me back some bucks, it did.

    I don't see how the bridge is manipulated and clamped in your pics?

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 8.  RE: Power Bridge Notcher

    Posted 04-19-2018 13:37
      |   view attached
    "What did you use for your cutterhead arbor/bearing setup. I had a machinist make mine, becasue nothing off the shelf would work..set me back some bucks, it did."

    See picture below. I'd have to do some serious digging to find my order for it - but it was indeed an off-the-shelf thing from somewhere - maybe Grizzly, but not sure. The shaft was a perfect fit for the Grizzly cutterhead.

    "I don't see how the bridge is manipulated and clamped in your pics?"

    If you look at the picture of my notcher with the springs. The black linear thing on the table to the right of my notcher is the rubber bladder clamp. It is set into an aluminum channel base. I has the blue air hose coming out of the end. That bladder clamp is simply placed on the table/bench with the bridge on top of it. You then inflate the bladder and it presses the bridge up against the bottom of the Delingit notcher base. If you look at the movie - perhaps pause it after it starts - you can see the bladder clamp in place - the bladder is directly under the bottom of the bridge, then you can see the aluminum channel base for the bladder and the bladder assembly is sitting on a hunk of spruce 2x4 to put it at a working height. The bladder only goes up and down about a quarter-inch, so you do need to have it within about 1/8" of its optimal height. Not difficult to do though - if I find it is not clamping well enough, I just jam a shim under the clamp and I'm back in business. If I were to do it all over again, even though the clamp I have works well - I do find that I need to have it positioned just right, I would look around for a similar pneumatic bladder clamp, but would get one about 18" long and twice or so as wide - that would just be easier to position - no big deal though.

    Does that paint a clear picture?

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 9.  RE: Power Bridge Notcher

    Posted 04-19-2018 14:40
    <but it was indeed an off-the-shelf thing from somewhere

    damn!...I used the Grizzly cutter as well, 1/2" arbor...could'a saved some bucks on that off the shelf part...damn!

    Ok, I get the bladder clamp.  Good ideas...congrats

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