Re: [Harp-L] Theft device shims (was Reed Slot Tolerance)


On Dec 4, 2009, at 2:24 AM, Michelle LeFree wrote:

If, Joe, by "vaulted" you mean that they have a convex curvature across their width, that's an important feature of these shims that makes them especially useful in my estimation.

Yes it sure does. The curved shims can be removed easily but the flat one is hard to free from the gummy matrix it sits in.

I actually find the vaulted shims more useful than the flat ones. I prefer to use a ~good~ reed wrench such as the ones in Richard Sleigh's toolkit to center errant reeds.

Yes, Richard de los Sleigh has a nice assortment of tools. The only reason I use the stuff I do is because I have had it since childhood. Grandfathers pass away, I get tools. Fathers & fathers in law pass away, I get tools.

The curvature in the cross-section of these theft device shims is what lends them the ability to shave brass off of reeds and combplate slots.

Ok, see here's the deal. There was a time when the 'they that say' kept everything to themselves because they had a rice bowl to protect. Bill Price, Vern, the late great Tate, myself, and several others, stopped this process by sharing. It was a secret that the EDGES of the curved shims were useful in shaving gunk (and even minute amounts of brass) from both the slot sides and reed sides. If you use them over clean white paper, with a little magnification (for us old people), you can see the debris hit the paper.

When I need to adjust the fit on a tight reed, I like to work the slot instead of the reed. The sides of the slots aren't perfect anyway because they have been punched. The reeds are usually shaper edged. You want sharp edges. In fact, as a punch goes into the brass, think of it punching through cheese. After a time, the entry will start to round off and the exit will have a sharp burr. I always believed the the exit was unimportant but the entry should be slurry honed to produce a sharp edge to the slots. A few microns is all that's necessary.

In cases of chromos, because the reeds are placed on both sides of the plate, the top should be slurry honed and the bottoms should be stropped.

Richard Slight demonstrates in his book how he uses narrow pieces of the shim stock that is included in his toolkits as Elizabeth suggests, to adjust reed profiles. You can count me amongst the folks who also use the theft device shims to remove not only burrs as Robert describes, but also to remove some chamfered or embossed material if I've over-done it a bit and the reeds stick after running a socket along a reed slot in the embossing process (see Buddha's Youtube video for a fine explanation of how to use a socket tool to emboss reeds).

Yes, embossing is good as long as the round object used is at least 12 times the diameter of the slot width. If the embossing tool is too thin, it will furrow too deeply into the plate and actually exascerbate the rounding off of the slot shoulders. Then the reed has to swing deeper and I think volume is lost.

To trim brass off the reedslot, the convex side of the shim has to face the reedplate and vice-versa to remove material from the reed itself. As Smokey says, the "vaulted" or curved cross-section of the shim causes it to be springy, giving some level of self- adjustment in the amount of pressure it !
can apply against the reed and plate. But which surface it will remove brass from is given by which side the convexity faces.

Exactly. This is because the edges of the foil strip are sharp and the metal, while thin, IS harder than the brass. You get the same effect with a cabinet scraper. All they are is a piece of hard steel with a 90 degree angle bent into them. This gives an edge that you can burnish and actually make the edge 'hook'. The drawing this hook across the wood will shave off minute amounts of wood. The edges of the shims do the same thing. They are actually cabinet scrapers in miniature.

One thing is for sure, they will shave brass off the reed or plate. You can see microscopic curls or shards of brass fall away as the shim is run through the slot. If there is a particularly narrow region between the reed and the edge of the slot, I run a shim through it several times. I prefer not to remove material from the reed as I don't want the action to impact its pitch, so I always ensure that the convex side of the shim is against the slot edge.

Me too unless their is a tight spot up by the rivet end. It's really hard to shave the slot up there, soooo I sometimes shave the reed. If anything the pitch would go down, so it's easy enough to raise it with one of my popsicle stick slips. Sometimes when I have a tight slot, I take a small slip of 600 auto body paper, insert it in the slot, and then with a little pressure on the reed, I drag the sliver up out of the slot.

All these may be subtle points but prior to Smokey's reference I'd never seen the curved cross-section of these super handy little shims mentioned.

It was pretty common knowledge among some of us. 6 or 7 of us would meet at Jerry Murad's house when he lived in Youngstown. I would get there at 5 and we would work on harmonicas and talk harmonicas. We exchanged ideas. (In fact Blackie and I also exchanged ideas with Rich Farrell). Alyce would make me soup...and sometimes a sandwich.

Anyway, at 7 the rest of the guys would show up and we would spend 3 1/2 hours playing ensemble arrangements. Then at 11, we would go to Perkin's for late breakfast. I really REALLY miss those days. GOD do I miss them.

Michelle




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