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Hammer tapering clamp

  • 1.  Hammer tapering clamp

    Registered Piano Technician
    Posted 06-23-2020 17:11
    Hi,
    I’m wondering if anyone has a picture of a hammer clamping jig used to hold the head for tapering with a plane?
    I seem to remember a photo posted by Glen Hart a few years back for just such an item. I’m interested in being able to taper hammers without the use of a tablesaw.

    Thanks,
    Joe Wiencek


  • 2.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-24-2020 07:56
    Joe,

    Check with Elizabeth Ward on that. Dale Probst used to have a jig for that task but I can't find the picture he sent me.

    Dale was always making/creating great shop tools.

    AG

    Allan
    Allan Gilreath, RPT
    Registered Piano Technician
    Allan Gilreath & Associates, Inc.
    706-602-7667
    www.allangilreath.com





  • 3.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-24-2020 14:41
    Thanks Allan,
    I appreciate the lead. 
    Joe





  • 4.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-24-2020 13:38
    Well, there's this one.  I forget who showed it to us; it was about 30 years ago.  It works OK, but not great.  There's no reliable way to keep the amount of removed wood the same on both sides of the hammer moulding.  When the jig is not in the vise, the hammer fits into the slot.  Then you tighten the vise to clamp it.  I made this in a hurry and never made an improved version.    





  • 5.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-24-2020 14:40
    Thanks David. I do like the simplicity of the jig. I suppose one could place shims under the already cut side to enable the equal tapering of both sides?

    Joe Wiencek





  • 6.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-25-2020 02:38
    Yes, I think that's what I did.  Plane one side, then flip it and add a shim underneath to plane the other side.  If you're careful you can do a passable job, but the Spurlock method is much faster and more accurate.  Also, with this jig you have to loosen the vise and reclamp the jig with each hammer, adding to the tedium factor.  I don't know why I made it so wide (scrap piece of of 1 x 4) unless it was to provide a wide surface for the plane so it wouldn't tip too far right or left, leaving an undesired chamfer, or bevel.  I did use it several times on "lesser" pianos where I wasn't doing the whole set -- just the top 15 or a few missing hammers. 
    --D.N., RPT

    ------------------------------
    David Nereson
    Registered Piano Technician
    Denver CO
    303-355-5770
    ------------------------------



  • 7.  RE: Hammer tapering clamp

    Posted 06-26-2020 03:06

    Hi Joe-  Here are some pics of the plane sled you mentioned.  I don't know how much experience you have with hand tools but I do know that very few techs know anything about using a hand plane so I'll just make a few comments to the general readership to maximize their chances of success. I wouldn't want anyone to invest a lot of time and money only to be disappointed.  

    If you're wanting to cut the hammer felt (and not just the molding), the blade must be ridiculously sharp. A good sharpening system will be a couple of hundred bucks - minimum.  One must know how to sharpen first and it's not easy to learn.  The reason I included the video is to assure everyone that what appears to  to be happening the the still photos is really being done and the secret is knowing how to sharpen.  The plane must be of high quality.  The plane in the photos is a Lie-Nielsen 164, low angle, bevel up smoother.  With a 12º bed and a bevel angle of 20º or less, it will slice right through the felt.  A regular 45º bench plane will tend to drag on the felt.  Mediocre steel has a crystal structure that is too large; it can't be sharpened if the crystal size is larger than the grit of the stone and   you'll have to sharpen down to at least 3 microns.  If everything goes right you should be able to get through a set of hammers without having to resharpen. After all of this, the first time you hit an errant staple, you're going to have a heart attack down both legs.  

      You can see in the pics how card punchings are used to position the hammer in the sled. You can cut the sides parallel or cut a taper by raising one end of the hammer higher than the other.  Since the plane rides on the runners of the sled it will continue to slice until it bottoms out.  I don't use it for tapering because it turned out to be slower than I was willing to accept, even though the quiet meditative nature of planing has a calming effect on my type A personality!  

    For a while it seemed like a lot of the hammers I was getting had distorted felt from being cut apart with a dull knife.  The sled excels at cleaning these up but just as effective is placing the plane upside-down in a vise and then sliding the hammer across the sole and into the blade. After building the sled I found it a lot less useful than I had hoped.  I have a setup to do all of this with a table saw, but where's the fun in that, and I already had the plane.  I was happy to later find out that the sled is fantastic for squaring and making parallel the faces of parts too small to be run through the table saw.  In retrospect, even though it looks cool and works like it's supposed to, I don't think I would build it again or recommend it to others because there are just too many alternative methods that are faster and give better results. 



    ------------------------------
    Glen Hart
    Grand Junction CO
    970-250-9596
    ------------------------------



  • 8.  RE: Hammer tapering clamp

    Posted 06-26-2020 03:48
      |   view attached
    I'll try the video again. Is there a time limit?  It was 53 secs.

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-250-9596
    ------------------------------



  • 9.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 07:21
    For efficiency and consistency, the best method of tapering hammers I am familiar with comes from my late, great mentor, Keith Hardesty. It consists of two disc sanders, rotating in opposite directions and facing each other at the angle needed for the desired taper. The hammer head rides into the two spinning discs on a carriage, tapering both sides at the same time, and resulting in consistent taper from hammer to hammer. (Sorry I do not have an image handy. Richard Davenport, RPT, had a PTJ article and cover photo of his version of Hardesty's tool. It was decades back.)

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 10.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 08:52
    Alan, I remember that article and picture from Richard Davenport in the Journal.  I don't remember there being any directions as to how to make the devise.  I took the article and picture to an industrial tool supply store that has a machine shop and they weren't real helpful.   They told me the electric motors in the picture were very expensive.  Back then the motors would have been about $300 each.  As I remember they suggested used motors.  At that point I looked into Bill Spurlock's method.  I bought two of his tapering jigs and keep them setup as one a left and one a right hammer side.  The entire process takes about 45 minutes to taper an entire set.  

    I do remember the setup and wished it was clearly presented.  I might have built the devise.  But I have what I have and is efficient for me.


    ------------------------------
    Tim Coates
    Sioux Falls SD
    ------------------------------



  • 11.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 10:17
    I have used a modified Spurlock jig for years. It allows me to make and check samples. I can change parameters on the fly. It is like a voicing tool.

    ------------------------------
    Mark Adams
    Artist Piano
    Solana Beach CA
    858-583-3333
    ------------------------------



  • 12.  RE: Hammer tapering clamp

    Posted 06-26-2020 10:29
    I really like a table saw to taper. I've been using my own jig but that Spurlock jig is what mine wants to be when it grows up. Is it still available?

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 13.  RE: Hammer tapering clamp

    Posted 06-26-2020 10:54
    Oh wait, it's modified. It gives me the idea to perfect mine during all this shop time.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 14.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 11:27
    What I find most important in my process is finding the front and back of the hammer.  It's important for me because I bore the hammers before I taper.  About 30 years ago at the National PTG convention in Philadelphia Chris Robinson did a class where he talked about how hammers are made.  He found there is a front and a back to the hammer.  It can have to do with the pressures in the clamping and the direction of the felt fibers.

    It is a simple subjective test.  If your hammers don't have a line drawn on them as they lay unwrapped, do so so there is a consistent side of the hammer (lineside or plainside).   Ray at Ronsen has confirmed that as you unwrap his hammers they are laid out just as they were when they came out of the clamp.  I don't know about other hammers because I only use Ronsens now.   Sample bore about six hammers throughout the scale, attach to a shank without glue using shimming paper to make a tight fit, and strike against string.  Listen for the better sound based on which side of the hammer.  You find the front or back of the hammer and have the line to guide you in boring, tapering, coving, tail shaping.

    ------------------------------
    Tim Coates
    Sioux Falls SD
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  • 15.  RE: Hammer tapering clamp

    Posted 06-26-2020 12:06
    I also bore the hammer prior to tapering, fits better in the jig. I also order the moldings uncoved (Ronsen can deliver this). If there is a cove, it's obvious which is the front. If there is a twisted staple, the twisted portion goes in the front so there is not chance for it to be snagged by the back check (oftentimes height is incorrect). I also order the moldings longer to accommodate the longest of a tapered bore, a 27mm tail + 3mm for trimming.  I trim tails to length after hanging and cut off the hammer shank protrusion and rough arc the tail on a bandsaw.

    I also start by removing the hammer which has the underfelt (if any) the only goes half-way across the molding.  Also, pre-weigh the set and remove any that are too high or low in weight.  Gang pre-file, bore, taper, weigh, and match to pre-weighed shank SW's to target curve.

    I don't cove al all because it removes so little and is a good spot to remove a few tenths of a gram when needed to keep the sides uniform.  Too many times a pre-coved molding restricts a sufficient arcing.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 16.  RE: Hammer tapering clamp

    Posted 06-26-2020 12:09
    A few years ago I purchased a Renner Hammer Drilling Jig offered here.  So while I'm at it:
    my slightly modified Brooks Jig is available for anyone interested. Photos available.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 17.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 14:11
    Maybe I'm lazy but (I have all these fixtures and don't use them anymore) I just tell Ray what I want and pay him to do it. He does a great job, and I do my strike weight calibration after installation. Actually he has a file on me so he knows what I like.

    BTW, I am now in love with bacon felt...fantastic! IMO.

    And made right here in Rochester, NH! 

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 18.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 18:36
    Glen,
    Thanks for the pictures and the video. I see what you mean about the sharp blade being essential. I have recently been reading Leonard Lee's book on sharpening, and realize that it's a much deeper subject than I was prepared for. I do have a fairly easy to use Renner tapering jig, but I don't have a particularly good table saw, and recently my situation makes it tough to use indoors. So the weather has to be good for me to use the saw outdoors.  I had thought of your posting of the sled earlier as a quiet and much less dust in the air solution to hammer tapering, but it seems there's more to it....

    Joe Wiencek





  • 19.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-26-2020 20:51
    Mr. Wiencek,

    Maybe you could get in touch with John Gallen at Brooks Ltd. He might be willing to share some photos of the system he uses with a table saw. My recollection is that it is set up for superior dust control. Thanks for starting this thread. I love it any time Glen Hart weighs in on some subject I had previously thought myself to have a decent understanding of.

    ------------------------------
    Karl Roeder
    Pompano Beach FL
    ------------------------------



  • 20.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-27-2020 11:13

    I've been reading this post through my peripheral vision always wondering how one adjusts the strike weight of the hammer/shank assembly having removed almost all the viable tapering material before the hammer is installed on the shank.   



    ------------------------------
    Roger Gable
    Gable Piano
    Everett WA
    425-252-5000
    ------------------------------



  • 21.  RE: Hammer tapering clamp

    Posted 06-27-2020 15:00
    I have my own tapering jig but since it runs on a 1-1/4" shaper, there's no point in sharing it.

    However, regarding weight control, I control hammer weight, rather than  strike weight, so the simple hammer weight is easy to target, when choosing how much to taper. I don't impose a hypothetical curve on a set of hammers, rather, I see what the set is going to allow me to achieve, and shoot for that. Given the felt density and molding densities, I measure weights at the ends of each section, and adjust weights to create targets points. Adjusting the weights will usually require tapering. Later, coving can remove an additional .3-.4 g from the tapered hammer. With the section beginning and ending hammers tapered and weighed, then just draw a simple "linear fill" in excel. I'm picky...but not overly anal regarding meeting the excel drawn weight targets.

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



  • 22.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-27-2020 15:18
    I suppose you would just have to order hammers that are heavier than what's ideal for the touch, i.e., get typical weights of hammers from the supplier, guesstimate the weight of wood ( and felt, if any) to be removed, and order a set that's heavier by that amount.  From what I've observed, all rebuilders taper, arc-sand the tails, and pre-file.  This only leaves coving for possible further weight removal.  I don't remember it coming up as a problem in the hammer replacement classes I've attended.
    --David Nereson, RPT    





  • 23.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-28-2020 19:23
    I taper for weight, as well, using a tweaked Spurlock jig at my table saw, setting up 7 increments (adjusting the tail side-positioning set screw by quarter-turns out to narrow the first sides of the hammers and then by half-turns back in for the second sides so the tapering is symmetrical). The widest tail is the lowest tenor hammer, the narrowest, of course, is the highest treble hammer. The highest bass hammer (by choosing its taper) equals the lowest tenor hammer in weight, removing the inertial shelf in my weighoff and helping my voicing. The coving is identical throughout but the outside tail shaping adapts to refine the hammer-to-hammer progression - particularly helpful where there is a change of wood density in the flitches that make up the moldings. I calculate the tapering to leave the highest tail slightly over 1/4" wide at the bottom. Roger Gable's point is well-taken - I pre-size my hammers to the molding width, setting up the Spurlock jig to hold the hammer parallel to the saw blade, i.e. I trim the variable felt.

    ------------------------------
    Christopher Brown
    chris@grandwork.tools
    978-505-7728
    ------------------------------



  • 24.  RE: Hammer tapering clamp

    Posted 06-28-2020 04:14

    Alternative to jigs: two vises-

           First of all: Karl, thank you for your comments; Jim, I also have a large shaper so I'm interested in seeing your setup; I'm always looking for new ideas.  Here are a few pics of a method of tapering hammers I came up with when commercial jigs were not available.  I prefer to buy tools that have multiple applications and are readily available (see the back check pic). The only modification made was an aluminum  jaw plate with a rectangle cut out at the corner to position the hammer. It could just as easily have been made of wood.  Low friction tape is applied where it makes contact with the table and fence. I much prefer running the "tapering jig"  along the fence instead of utilizing the miter slot.  For years I used the Unifence but a few years ago I purchased an "Incra Fence" and it is so much better I don't know how I got along without it - ideal for dialing in the perfect cut on the hammer.  It is precise to a thousandth and instantly repeatable without going through the seemingly endless tap, cut  and test process.  

           One of the pics shows a small die maker's square being set exactly to the taper angle.  I use the square later in the process when I hang the hammers.  It adds no time and subsequently I spend very little time having to match hammers to strings. Having a precise and consistent taper is critical to my system.   Several years ago I forgot to taper before I shaped (arced) the hammers so I had to use my sander system to taper. Many of you "old timers" might remember the "Hart HammerSmith" from conventions during the 80"s & 90's. It's a good machine but there was still some slight variation.  I proved (to my own satisfaction) that it is next to impossible (in a reasonable amount of time) to square hammers if there is the slightest variation in taper angle from one one side of the hammer to the other or from hammer to hammer.  I think a large portion of the time spent on lifting strings and filing hammers comes from hammers that are just slightly out of square but not apparent to the naked eye.
           As far as touch weight is concerned,   I do my homework and know my target hammer weight, before I ever start. One pic shows how I can tweak hammer weight after glue-up.  The machine is a knife maker's belt grinder and is one of my most favorite and versatile shop tools.   I'm meticulous about friction and the system that most appeals to me is the Stevens/Vanderlip method.  I hope I'm not over doing it with all the pictures but no one has ever seen these before.  Please let me know if I am.



    ------------------------------
    Glen Hart
    Grand Junction CO
    970-250-9596
    ------------------------------



  • 25.  RE: Hammer tapering clamp

    Posted 06-28-2020 10:45
    Here's my tapering jig, Glen. 1-1/4" shaper, with 8-1/2" Forrest Tablesaw blade, center bored for 1-1/4", running horizonal, with heavy 4" indexable shaper head as blade stabilizer.  I used this setup for power fed cutting deep door jambs rabbets, in the olden days.  

    two positions on the tapering jig. One for each side of the taper.
     
    next pic shows two hammers running in one pass. I never do this actually...only work one hammer at a time, moving to the second position for the second taper.

    I have used the cheap Palmgren vise, as Glen does, as a base for jigs. Here's my boring jig. Found the rotational center, and set it up to index off that center. Molding is held at at the rotational center. Shims adjust for various molding sizes set to set.

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



  • 26.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-28-2020 11:23
    Mr.'s  Hart and Ialeggio,

    Thank you for taking the time to post both your descriptions of process and the accompanying photos. For my part there is no better use of this forum than what you have offered. Seeing well thought out shop processes makes it so much easier for those of us without formal training in machining or woodworking to understand what is possible. It also keeps each person new to the work from having to invent the entire profession from scratch. 30 or 40 years ago finding this sort of information was near impossible. Please keep sharing.

    ------------------------------
    Karl Roeder
    Pompano Beach FL
    ------------------------------



  • 27.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-28-2020 11:03
    Glen and Jim- fabulous milling I'm very grateful for your sharing it. Glen could you comment further on the Stevens / Vanderlip method , please?

    Thank you-

    DB

    ------------------------------
    David Brown
    Garland TX
    ------------------------------



  • 28.  RE: Hammer tapering clamp

    Posted 06-30-2020 00:49
    Hi David -Thanks for the compliment. I may have misspoken when I called it the Stevens/Vanderlip Method; I think it's more properly called the "Double Stack Weigh-off Method" developed by Steve Schell. I think I should defer to someone else on this subject for several reasons, not the least of which is that I'm not qualified and also I have grand kids visiting this week so I'm signing off for a bit.  Maybe Bruce Stevens, or David Vanderlip could  teach us.  The class they give is excellent.

    ------------------------------
    Glen Hart
    Grand Junction CO
    970-250-9596
    ------------------------------



  • 29.  RE: Hammer tapering clamp

    Registered Piano Technician
    Posted 06-28-2020 12:00
    All,
    Unfortunately, you cannot predict an accurate gradation (from bass to treble) of hammer weight or strike weight by pre-setting a specific taper amount on a gig. I have found that the felt density alone can vary by as much as .5 grams from adjacent hammers, especially at the tenor break.If you multiply the .5 gram variance by 5, you could experience slightly over 2 grams of down weight variance from key to key. I hang the hammers first, weigh the assembly, and hand taper and cove to exact no more than .1 grams from hammer/shank assembly to hammer/shank assembly. If you combine that process with independent key lead adjustments to even out the key inertia, you will find the touch weight (up and down) is so accurate no pianist could detect a jump in inertia from key to key.
    Roger 





  • 30.  RE: Hammer tapering clamp

    Posted 06-28-2020 13:57
    When setting up to hang hammers, I weigh the hammers and discard the outliers (hi-low) and the one with the underfelt half-way across the molding.
    I measure the SW of each shank and separate into groups. Then I match the shank SW with the hammer weight to get as close as possible to a desired curve.
    The curve will be higher since the tails are not yet arc'd.

    Shanks will have a SW of anywhere between 1.4g and 2.2g.   So if you inadvertently selected a hi-SW shank for a Hi hammer weight and then a lo-SW shank for an adjacent Lo hammer weight, you resultant SW difference could be around 1 gram which is problematic in graduation terms. The appropriate method would be to purposefully select the lo SW shank for the hi-hammer and the hi-SW shank for the low hammer and their resultant Sw's will be close.

    Since there is a broad range of shank SW selection, matching to hammer weights reduces the work needed to target your SW Graduated Curve.

    To further complicate matters, I measure the knuckle height and try to place those hi/lo's-of-the-average at the ends; or at least grouped hi's and lo's together.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------