Hi Doug,
Suppose I start by giving the report I had planned, with the photos I have (only of the sanding paddles), and you can supplement with other details and photos.
Ted's basic idea is that we should be able to do a quality upright hammer filing job on site, rather than take the action back to the shop. The first problem is to hold the action securely in place. This he does by using something extending from the action bolts: he showed the Schaff telescoping brackets (aluminum), but prefers his own home made ones, of which he showed versions in brass and wood. I'll describe the wooden ones.
A strip of wood about 1/4" x 3/4" x 8". Attached to each end is a sort of home made flange, about 1/4" x 3/4" x 1 1/2" with a 1/4" cutout. The "flanges" are attached to the longer strip by a finishing nail: drill a hole slightly undersized, drive in the nail, clip off the end. The flanges have a hole drilled in them. The hole should fit the action bolt fairly snugly, and then it won't even be necessary to secure it with a nut. The other flange will be attached to the action bracket by means of a machine screw (bolt) and a wing nut.
Place the bottom of the action brackets on the cheek blocks (padded), and secure the action in place with the devices described above. Now the action is held securely with enough room to work between the strings and the hammers.
The other main element of Ted's method has to do with using curved sanding paddles. For the straight bored hammers, he uses a gang filing method, doing about 4 hammers at once. The tops are done with a straight paddle, and he makes this efficient by having a paddle with four grits on it: 40, 150, 320, 1000. That paddle is about 2 1/4" x 4 1/2" made from plywood from Lee Valley Tools, I think two thicknesses of 2 mm plywood. There are two grits on each side of the paddle, as you only use a small portion of the paddle to actually sand (the fingers are holding the other half).
But the curved paddles are at the heart of Ted's method. For gang filing, he has paddles that have been shaped into a curve by pressing them around a form - he used the liner from his glue pot. Two pieces of 2 mm plywood are cut to size, glue applied, to one side of each, then they are clamped against the glue pot using wood cauls made for the purpose. This creates a nice curved shape that will reach the bottoms of the hammers. With these paddles, only two grits are possible on each, so there is one with 40 and 150, the other with 320 and 1000.
For the angled hammers, he made individual paddles to reach the top and bottom of the hammer. He cut these out of a piece of wood 1/2" thick, cutting holes 2 1/4" in diameter (the largest Forstner bit he could find). Half of each hole serves as the surface for a piece of sandpaper (the photos will make this clear). There is one "paddle" for each grit. To one side of each paddle he glued a piece of 2 mm plywood, which gives a surface to bear against the side of the hammer while filing it, so it will be easy to keep the paddle surface square to the hammer.
That is the basic story. There were other details that perhaps Doug will add. Photos attached.
-------------------------------------------
Fred Sturm
University of New Mexico
fssturm@unm.edu http://fredsturm.net "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
-------------------------------------------
Original Message:
Sent: 08-23-2013 12:52
From: Doug Garman
Subject: Ted Sambell's Upright Hammer Shaping Class in Chicago
Hi, Virginia.
Indeed, you missed a wonderful class. I took a few notes, but mostly I took lots of pictures. I would be glad to share any and all of this with you. I have not contributed much to this list, so I am not sure the best way to share what I have with you.
-------------------------------------------
Doug Garman, RPT
Piano Technician
Arlington TX
817-578-4796
-------------------------------------------