Re: [Harp-L] B-Radical -- why is it great?

[Joseph Leone <3n037@xxxxxxxxxxx>]

The problem seems to be that when you design a part and turn it over to a machine shop, the first thing they will ask you is: "What's the tolerance?". Meaning: how many thousandths (of an inch/mm) do these parts have to be within the specifications.

So..let's say that you say ONE thousandth. This means that the part can be between (let's say) .099 inch, and .101 inch. The problem is that the receiver part, in this case a reed plate is ALSO subject to a tolerance. Where you may run into trouble is when you place a part that is 1 thousandth oversized into a perfect plate, or a part 1 thousandth undersized into an oversized plate, or the various permutations of the aforesaid tolerance variables. You may wind up with reeds that are too tight, too loose, or good. It doesn't take a rocket surgeon to see that you only have a one in three chance of getting it all right. 

So..what I'm saying is that when you try and build something, there are enough 'OUTSIDE' events present to cause problems. And I think that this is what may possibly have happened..to some extent. Parts weren't to spec.? Then adjusting for this is a proverbial joke, will take a lot of time, and throw your schedule out of kilter. As a business systems analyst, you need to find these faults and expedite their removal. 

Making a reed from a razor blade is not hard. Just time consuming. It's hard to find a drill small enough for the rivet hole. So, I took a sewing machine needle, tapped it on the blank till I raised a dimple on the opposite side. Then I filed the dimple till I had a hole. I used a bead reamer to open up the hole. I used a shoemaker's ladies heel tap nail as a rivet. You must NOT try and cut the rivet boss as a square. The inside corners of the pad are too hard to cut cleanly. You usually get a rip in the metal. Better to use a triangle shape.with a gentle transition (45 degrees..not 90) from the main shank to the pad. To 'ease' inside corners. I cut close to shape and then use a manicurist's diamond coated fingernail file to finish to size. 

The job takes 2.5 hours for a stainless Wilkinson sword STAINLESS blade, or about half that time for a Gillette or Shick super blue REGULAR steel blade. Coat the edges of steel blades with chap stick and they won't rust easily. Naturally you check them every so often.  The stainless don't need checked. There are several people now in possession of diatonics with these blades. 

smo-joe

On Mar 8, 2016, at 6:04 PM, Rick Dempster wrote:

> ---------- Forwarded message ----------
> From: Rick Dempster <rickdempster33@xxxxxxxxx>
> Date: 9 March 2016 at 10:04
> Subject: Re: [Harp-L] B-Radical -- why is it great?
> To: Vern <jevern@xxxxxxx>
> 
> 
> One thinks "Tucker Torpedo", "Delorean". I think Vern was talking about
> making reeds, not reed plates.
> The thing that occurs to me first and foremost, as being the most difficult
> and expensive, is, indeed, reed plates.
> I hadn't even got as far as the reeds. Joe Leone, if I recall correctly,
> once mentioned making a reed out of a
> razor blade.
> RD
> 
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