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Coving hammer tails

  • 1.  Coving hammer tails

    Registered Piano Technician
    Posted 06-05-2015 22:53
    Hi gang,

    Just wondering, for those of you who shape their own hammers, what's your method for coving the tails?  If you use a forstner bit, what size is it?

    Thanks!

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    Zeno Wood
    Brooklyn, NY
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  • 2.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-05-2015 22:59
    Zeno

    I don't shape my own hammers, but have on occasion sanded out the inside of the tails with small disc sanders. Kind of like the small ones for the dremmel, but with a larger diameter. I don't even remember where I got them. I had them back in St. Louis.

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    Willem "Wim" Blees, RPT
    Mililani, HI 96789
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  • 3.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-05-2015 23:59
    Wim - I think you meant 'drum' sander, not 'disc' sander.

    Zeno - Assuming you'd be doing it with drill press.  I think Dremel would be too light weight for a whole set.  Here are a couple of sites that might be useful:
    : http://www.gregdorrance.com/sanding-mandrels-drums-c-51_427.html

    http://www.woodcraft.com/search2/search.aspx?query=drum%20sanding%20kit

    or this:
    http://www.harborfreight.com/catalogsearch/result?q=drum+sander


    Forstner is less dusty but I never liked the way they looked.  Hoping maybe to learn something from other responses.
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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 4.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-06-2015 02:00
    I use forstner bits. The size can vary and isn't critical. I think I use a 3/4" but have used 1" or even 1 1/4". Make a platform to hold the hammer in place. Goes fast. ------------------------------------------- David Love RPT www.davidlovepianos.com davidlovepianos@comcast.net 415 407 8320 -------------------------------------------


  • 5.  RE: Coving hammer tails

    Posted 06-06-2015 06:47
    The quickest method is with a Forstner bit. The hammer needs to be clamped to the surface. I stopped when I realized that it was only removing .3 grams or less from the hammer and was not worth the effort. No bang for the buck. The time it takes to mill out the area produces only a 1.5 to 2 grams weight reduction at the front of the key. Negligible return for the work expended.

    When installing new hammers, I order them uncoved. If I need to remove a few tenths of a gram, I can remove wood from the front of the tail on an oscillating spindle sander and not alter the profile of the hammer above the shank. It's a good bank for wood extraction. There is no tonal benefit to the cove. Many times, the pre-coved molding did not allow for the tail arc I wanted to establish.

    The oscillating spindle sander comes in handy for reshaping/resurfacing hammers. I've dressed knuckles and thinned shanks with it too.

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    Regards,

    Jon Page


  • 6.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-06-2015 08:08
    Funny (as in 'interesting') how wedded I am to the visual aspect of coves, even granting the reality of what you say.  
    Re: Osc. spindle sanders.  Do you have any recommends/cautions with regard to bench top models?

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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 7.  RE: Coving hammer tails

    Posted 06-06-2015 09:03
    I have a Rigid Oscillating Spindle Sander from Home Depot. It came with an oscillating belt sander attachment.

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    Regards,

    Jon Page


  • 8.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-06-2015 10:52
      |   view attached
    You don't have to clamp the hammers if you build a simple platform like this (see attached).  You can hold the hammer in place easily with your fingers as the tail butts up against the stops and keeps it from drifting.  This is a 7/8" Forstner bit.  The final tailed and tapered hammer is also pictured.

    I agree that coving accomplishes little in terms of weight reduction.  However, I find that it does save me having to check to be sure that I'm tailing the correct side of the hammer and I do prefer the look.  It also offers a convenient place to number the hammers.  

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 9.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 10:25
    Thanks everyone for your responses.  I've been looking at a typical Steinway hammer and trying to figure out how you might make that sort of cove - perhaps a little router with a jig set up to mill out that part that isn't part of a circle's arc.  Beyond my ability or willingness to get into it that deep.  It looks pretty nice though, I find it more attractive than the cove produced by a forstner bit.

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    Zeno Wood
    Brooklyn, NY
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  • 10.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 10:58
    Zeno -
    Allowing for how much I don't know, I'd stay FAR away from routers for this application.  As David L pointed out, with a Forstner bit, you don't have to clamp the work, just have a way of capturing it.  With a router, you can almost guarantee that some hammers (or fingers) will have stories to tell.

    If, in spite of the acknowledged limited weight benefits, you want to emulate the Steinway profile, you could either do it as a two step process (forstner, then drum sander) or with drum sander (Jon P's oscillating spindle sander) alone.  The actual shape IS in two stages: the actual radiused cove (3/4" diameter), to the exact center line of molding, and then the (flat) removal of material, to 1/8" from center line.  If you're hanging using a jig that uses the inside/bottom of tail, as does Spurlocks's, it's very important that whatever you do leaves that measurement consistent. 


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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 11.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 11:05
    This is why I always get my hammers pre coved and tapered. I like my fingers!

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    Paul T. Williams RPT
    Director of Piano Services
    School of Music
    813 Assembly St
    University of South Carolina
    Columbia, SC 29208
    pwilliams@mozart.sc.edu
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  • 12.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 11:24
    Do you have a favorite?

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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 13.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 07:44

    David 

    I like Abel Naturals from Brooks best. Second is Steinway.
    -------------------------------------------
    Paul T. Williams RPT
    Director of Piano Services
    School of Music
    813 Assembly St
    University of South Carolina
    Columbia, SC 29208
    pwilliams@mozart.sc.edu
    -------------------------------------------




  • 14.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 11:33
    And I think that's a good idea if you are uncomfortable with the machinery required to do that job.  The Forstner method of coving offers little risk and the use of a sander (Spurlock Jig) for tapering also offers little risk.  I wouldn't use a router for coving and many are uncomfortable with the table saw method of tapering even with the protective Spurlock Jig.  

    The cost of having these things done by the manufacturers is usually pretty low so there's good reason to just have it done.  It does require them to bore the hammers as well, however, and I often find that a stock bore is not correct.  Steinway won't do custom boring. Also, I often find that the amount of taper needs to vary some in order to achieve a specific target weight.  This is true especially on Steinway hammers (though I rarely use them) that can be bulky, especially in the treble.  

    I think it's important to be able to do these procedures when necessary or work with someone who can do custom work.  Renner, Abel, Ronsen, all will do that but it means you have to use their products which may or many not be right for the given job.    

    Worrying about emulating the Steinway profile for the cove provides no particular benefit and I would say is not worth the trouble.  

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 15.  RE:Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 15:35
    Great post David, and I couldn't agree more with this:

    "Worrying about emulating the Steinway profile for the cove provides no particular benefit and I would say is not worth the trouble."



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    Kevin Fortenberry
    Registered Piano Technician
    Lubbock TX
    806-778-3962
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  • 16.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 16:54
    I used to think the same way. 

    There was a class taught by Chris Robinson in Phillie back in the 90s where he talked about a front and a back side to hammers.  The only way it can be found is to use several raw treble hammers that are bored with no tapering, coving, etc. and switch front and back orientation.  Which ever positioning sounds the best determines front or back.  I didn't think it worth the trouble until I decided to try it.

    It means one has to bore, cove, etc. hammers in the shop, but I find it worth the effort. 

    To each his own, but Chris Robinson was right in my book about this.

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    Tim Coates
    Sioux Falls SD
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  • 17.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 17:02
    I meant to be replying to David Love's post concerning paying the hammer makers to do the tapering and coving.

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    Tim Coates
    Sioux Falls SD
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  • 18.  RE: Coving hammer tails

    Posted 06-07-2015 11:39
    I order hammers without any secondary processes. When it comes to coving, I use it as a final weight targeting reduction or not reduction. By the time I cove, which is the last hammer prep process I do, hammers have been tapered, in varying amounts, as per the hammer weight curve I have been targeting throughout the hammer prep process. if my hammer weight is within .4 grams of target hammer weight, the final coving can take care of this discrepency.  I cove, using a cheap 1" sanding drum mounted on an otherwise useless craftsman drill press. I process freehand, by eye, checking hammer weight as I remove whatever is necessary to reach my weight curve target. In order to get a smooth weight progression, often, almost no coving happens in the low tenor to smooth the weight differential between bass and tenor. Then as I progress up the scale, more coving happens, but how much or how little is determined by the target weight curve.

    The coves are never visually consistent, as prioritizing the visual over the functional doesn't make any sense to me here.  

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 19.  RE:Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 15:50
    Jim, EXCELLENT post - brilliant! Although I completely understand aesthetics/taking pride in our work ie; "the look" of even coves. The extra trouble in this particular case- well, no one will ever see it in real life. (Very unlikely anyway)
    AND, if this area can be taken advantage of for evening out the weights- PERFECT. That is something that to take pride in, etc.
    Perhaps those of us who usually order our hammers pre-bored, tapered & squared- we could specify to leave extra wood on the tail coves in order to have a nice option just for evening out hammer weights.
    Kevin

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    Kevin Fortenberry
    Registered Piano Technician
    Lubbock TX
    806-778-3962
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  • 20.  RE: Coving hammer tails

    Posted 06-07-2015 19:30

    On the other hand I like to cut the cove off the bore so that the cove is parallel to the arc of the hammer, which I also shape off the bore. Here's the platform I made for this purpose.

     

    Picture 77 shows the platform with a transfer punch held in with a set screw. You could use a shank or a drill bit for this purpose. There is another set screw that supports the side of the hammer. I typically cut the cove after tapering the sides so I adjust this set screw to support the hammer at the right height. I pretty much always go for a 1" tail length and use a 7/8" forstner bit for the cove operation.

     

    Alan McCoy






  • 21.  RE: Coving hammer tails

    Posted 06-07-2015 21:10
    I think you may find that a 1 1/16" (27 mm) tail length regulates better with the back checks without the tenor shoulders bouncing off or scrubbing the tops.

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    Regards,

    Jon Page


  • 22.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 05:33
    Alan -
    Nice jig and photo.  Wondering if you could post a couple of completed hammer, especially bass or low tenor.  Curious as to how the angles all work out, compared to a 'flat' coved approach.

    Unless anyone is proposing that pre-coving has a mechanical benefit, we are, by pursuing this discussion, admittedly parsing the visual elements and how we execute.  

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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 23.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-07-2015 19:12
    Also small holesaws work quite well.  I have both but generally use the holesaws.  Fewer chips. 

    In either case, half the battle is to have really sharp tools and an effective clamping arrangement.  

    If you're into micro-adjusting hammer mass, size of cove is a very effective way to address that concern -- either by going smaller or larger.  





  • 24.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 06:15
      |   view attached
    I'm in agreement with Jim.  Function over form.  Back in the 1980's I was using very light soft pressed hammers from Ronsen with lot's of tapering.   I made the coves by first drilling with a Forstner then making a saw cut to finish.  I used a Hammond Glider Saw for the precision cut.   It made for a very beautiful hammer tail with minimal material.  see attached

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    David Stanwood
    Stanwood Piano Innovations Inc.


  • 25.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 08:58
    And there's the dilemma, as that's one gorgeous looking hammer.  Sigh

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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 26.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 14:30
      |   view attached
    Nice looking. I have to admit I prefer a more sturdy tail.  On occasion voicing procedures call for setting the hammer tail on a block and pounding the crown with a small hammer or the back of a voicing tool.  These types of tails I've seen give way.  Similarly, tails that come to a very fine point.  It looks elegant though.

    Unlike a few others, I prefer to cove first.  I do like the uniform look of coving and also prefer to number and orient the hammers consistently front and back before I begin (after the cove is cut).  Form and function don't need to be mutually exclusive.  I've heard the reports on different tone depending on which way the hammer faces but have not been able to duplicate that on any hammers that I typically use (Ronsen Weickert and Wurzen).  The first report of that I heard was on Renner hammers.  

    When I have to adjust weight on hammers it's often more than .1 or .2 grams and so the cove area is not a good place to get that from.  I prefer to build up weight rather than take it down and so precalculate the hammer weights in advance based on my action ratios and touchweight and inertia targets and make sure I'm in the ballpark or not exceeding that by much, if any.  There are invariably some outliers in a set.  I don't do the final strikeweights until the hammers are hung, usually, and just go through, remove them from the rail and check them and adjust as needed.  I use that same removal time to check the friction on the center pins and treat as needed.  To add weight, of course, the solder method is the easiest.  To remove additional weight I use a plane set in a bench vise and shave off a bit of the hammer by hand (see attached). Shaving the felt along with the molding will remove weight the quickest and can be done easily with the hammers on the shanks. I usually use a notched 3/4" dowel to push the hammer through to save my fingers from any slips.  

    But to each his own.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 27.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 15:03
    BTW for those looking to duplicate the Steinway cove I believe those are done en masse before the hammers are cut apart.  I would guess that they are run through a router set up and the whole set shaped in one quick pass.  Duplicating that by hand, one at a time, is really impractical with no real benefit.  



    -------------------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 28.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 20:16


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    Tim Coates
    Sioux Falls SD
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    David,

    In the spirit of to each his own.

    I too use pretty much Ronsen Weickert and Wurzen hammers with the occasional Isaac Credenza set thrown in there.   I find tonal differences in all the sets.  I also verify my results by asking another technician to do a blind tone test.  I'm lucky two other techs besides myself hear the tonal difference.


    Thanks,
    Tim Coates


    Original Message:
    Sent: 06-08-2015 14:30
    From: David Love
    Subject: Coving hammer tails

    I've heard the reports on different tone depending on which way the hammer faces but have not been able to duplicate that on any hammers that I typically use (Ronsen Weickert and Wurzen).  The first report of that I heard was on Renner hammers.  

    But to each his own.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    -------------------------------------------




  • 29.  RE:Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 22:26
    Tim, David, & other Wurzen/Weicket lovers. I'm planning on trying some of these out. For example, we just moved a Yamaha C7 into our Band Hall last week. I'm going to file/voice/regulate to get us by for a while (original Yam hams.) but am wanting to get some thoughts on what some of you have experienced with using Wurzen or Weicket hammers (w shanks flanges-pre-hung) Although our Band Hall is fairly live, I do want it to have a fairly bright/powerful tone.
    I have been using Abel Naturals which have turned out nearly perfect for last two pianos I did: (Baldwin L and the Steinway L). They would probably require juicing/lots of filing in the Bass half for this particular setting.
    Or, should I consider ordering Yamaha hammers, shanks/flanges.
    Kevin

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    Kevin Fortenberry
    Registered Piano Technician
    Lubbock TX
    806-778-3962
    -------------------------------------------





  • 30.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-08-2015 23:13
    Kevin -
    Please repost this with a new subject.  Others, please don't respond until Kevin re-posts.  Nothing personal, but this ignoring of subject headings is getting out of hand.


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    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565
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  • 31.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-09-2015 01:52
    Since I don't prefer to use hammers that require lacquer at all or where lacquer may be required I probably wouldn't use them in this case. If you wanted to then I would use Wurzen but in a low profile configuration only. They will be somewhat brighter. I don't have any problem with the current Yamaha C7 hammer either, given your described goal. As long as they give you the good stuff. An Abel natural with lacquer is something I would avoid under any circumstances. You can copy this to a new thread if you prefer. ------------------------------------------- David Love RPT www.davidlovepianos.com davidlovepianos@comcast.net 415 407 8329 -------------------------------------------


  • 32.  RE: Coving hammer tails

    Registered Piano Technician
    Posted 06-09-2015 18:28
    Form follows function has been one of the guiding principles of the modern era.  But I prefer Buckminster Fuller, form and function are inseparable.  

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    -------------------------------------------