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I designed and built this router jig based on a planing process described by Bill Spurlock in a 1991 Journal article. His article described a process using rotary planer device in a drill press. As I approached this project, my thinking said that he had everything right, in terms or process. What it think this jig does is to improve accuracy, speed, and safety. I'm sure others have built similar, but I wanted to share it with you all, since I haven't seen a jig quite like this one documented.

More photos at Flickr

The photo to the right shows the key after exiting the jig. Note that the clamping mechanism is a simple, quick lever which holds adequately and keeps the process moving. The loose plate between the key and lever is coated on the lever side with some beads of hot glue, to provide gripping surface that would not be present in the hard maple. The router bit is a 1-1/2 diameter flat cutting bit. Since the key is less than 1 inch across, this diameter provides a cutting surface for both left side and right side of the key. Order of operation is:

1) With jig against right shoulder insert into about 1/4 inch. move to the left to plane the front edge of of the key (and the existing key front).
2) Slide the sled in to plane the left side of the key.
3) Move the sled to the right, forming the nice edge at the back of the key.
4) Pull the sled out to plane the right side of the key.

This order of operation will provide for proper rotation orientation of the cutterhead and produce a splinter free surface.

The jig has a dust collection port at the rear. That is 100% effective for the first and second cuts. For the last cut ( pulling the right side of the key out), some debris exits from the front. I think that another suction point to the right of the router base would catch that bit of shavings. I'll try that when I do the next set of keys.

The objectives of accuracy and speed are met. This set of 52 keys was planed in 45 minutes.

Hello, THAT is interesting, thanks for sharing. I have seenn one similar setup but with another fixture for the key, and I was waiting to see other information before making one (I rarely have to change the key tops)

Which is the reference surface on yours ? (I guess the right side of the key.

It seem to work fine, no problems with warped keys ?

Would not a slighly elevated surface work better, you will have long and warped keys on grand pianos ?.

I also was believing that the sides of the key where the best reference to have the top square (not the underside) but your setup allow to use one or the other, and shim if necessary.

I guess that in fact having 2 supports (one left oriented and one right) would be better for consistency (?)

do you have a valid link for a sketch, or the original one from Bill Spurlock ?

Thank you again.

The Spurlock article which was my beginning point is the March 1991 issue of the PTG Journal.

The key set I worked with for this first go was really in good shape. There were no warped keys. I would say that the left side of the key (in the photos -- right side in the piano) is the reference edge, and that the jig makes a cut perpendicular to that edge. The loose plate adjacent to the lever has less bearing surface than the fixed block. To set the clamp, I provided a light down pressure for reference to the sled's top, then clamped it tight against the block.

For this key set, the tail was relieved relative to the ivoried key length, so the back of the key was actually not in contact with the sled, but a millimeter or two above the sled. But I can see that an elevated contact points at the front and rear of the ivoried key length would eliminate problems for another key set. For this one, I judge my success by the uniformity of the rear profile of the cut.

The width between sides of the jig is 300 mm. The sled is 262 mm wide. Other dimensions are determined by the key. I'm giving you my working sketch here: http://www.flickr.com/photos/duanemcguire/4150416852/sizes/l/ Consider it to be my starting point. I know it is not an "as built" diagram, since I went direct from concept to finished product. In particular the sled and base are longer than indicated in the sketch. They were built to a more "comfortable" length.

The base and sled are made of melamine faced particle board for slipperiness. The inserted end of the sled has a pair of sliding closet door rollers on it for smooth use and to assure that particles on the floor of the jig do not interfere with the reference cut.

'Looks interesting. What is the plated hardware on the front of your slide, and what is its purpose?

Had you thought of putting another clamp on the tail section of the key?

Very nice

The plated hardware on the front of the slide are rollers sold as sliding door glides at the local Lowes hardware. The purpose is to make the cross cut smooth. Also by using the roller point above the floor of the jig, any chips/debris that the dust collection misses will not interfere with a true reference to complete the straight cut at the back of the key.

I found that the simple quick clamp was trouble free and solid for this key set. Another clamp at the rear of the ivoried section would provide additional security. I was going for for the min-max of hardware/accuracy. For this key set it was perfect. I expect it will evolve some with different key sets in the future.

Hello Duane, thanks so much for the pics and detailed sketch, I appreciate a lot (sorry not to answer before, i finish very late those days)

I just collected the wood (a bakelite coated of very hard plywood used for stocking of heavy goods, after truck delivery). I'll post pics when I will be done (in a few weeks).
The little rollers on the edge are a really good idea. I guess the quality of the chips aspiration is important, no chip may be allowed to insert under the support.

Best regards.

Your setup is perfect for keys which are flat on the bottom. What do you do with keys which have plates on the underside of the key at the balance rail?

This was a first go, but I believe that I'd place elevated plates on the sled at the front and the rear of the ivoried portion of the key. That would elevate the key and the plate would clear. For a temporary setup they could be affixed to the sled with double-sided tape. Alternatively a trough could be routed in the sled to accommodate the plates.

It will be interesting to see how it evolves.

Duane, just saw your web site, I like your adjustable height assembly bench! Do you have any contrast/comparison to the Noden bench?

I'm planning on building or buying an adjustable bench, maybe copying your design.

I also had a look, you gota nice place and good jigs /tools.

Nice work on the Chickering.

If someday you find a piano with all the ribs unglued, like I find, you can try to reglue all the ribs (with hide glue in my case as, this glue really add tension within the glue joint), after having dried a lot the panel (protecting the rest as you can). After that the panel get resilient an dynamic, it was surpising to hear a 1926 piano that sounded like if it was younger (not perfcet, but those treble where singing and long and the dynamics really grow up)

Too much work to be financially interesting but it was a good experience, and it certainly sound better than another one I have with a "perfect" soundboard,(no craks, minimal downbearing, very good tap test) but as the panel age it retract and loose crown /internal constraining, as we all know, and the dynamic will be poor.

Sorry if the subject is to be placed eslewhere.

Next one, I'll try to unglue the soundboard and rib it again if possible.

Thanks for the comments Isaac. The piano soundboard work you found on the website is actually a Stieff 6'2 of 1911. I love your expression "too much work to be financially interesting"

Jim: the adjustable assembly table was a fun project too. I'll start another thread on that one. Could be of interest.