Re: [Harp-L] Reed slot needs to be shortened

[Vern <jevern@xxxxxxx>]

I have been experimenting with my recently-completed  DIY Capacitance-Discharge Reed Welder. Key components are a 1 farad 20V car-audio capacitor and a power thyristor with a 1000 amp surge rating.  

Forget filling the tip-end and consider the following for "shortening" the slot.

Simply weld the reed .045" down the slot where the tip is correctly located with respect to the tip end of the slot.  Now a part of the reed base is straddling the slot.
A welded-on reed doesn't care where the rivet-holes are!  You can put four welds in the four corners of the reed base for a very secure attachment.
Now put a dab of epoxy in the slot under the reed base to support it from the bottom and block any leakage through the holes.
The placing of the epoxy isn't nearly as critical as it would be at the tip end where the reed is swinging through the slot and you have to maintain a close, square, .001" clearance.

Using this method, you could conceivably install the shortest reed in the longest slot!

One could also use a reed longer than the slot.
By rounding off the rear end of the slot so that the reed doesn't touch, the base of the reed could be moved back.  That might be better than using solder to lower the pitch because you could use a standard reed.

Spot welding opens many interesting possibilities...as Suzuki has no doubt already figured out.

Vern
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> On Oct 29, 2010, at 10:56 PM, Doug H wrote:
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>> I got back some custom made reed plates from my EDM guy only to find that one of the slots was mis-cut a about .045" too long (in .040" thick brass - slots are .0835 wide).  I recall a discussion here a while ago about how to shorten a slot.  I believe epoxy and/or solder were mentioned. My plan would be to try and gracefully place a gob of epoxy or solder in the end of the slot and then file it into shape.  Or should I try and make a little plug of brass and then solder that into place?  (I have lots of brass scraps.)
>> 
>> I have 8 of these to fix so it is worth doing a bit of research first.  All advice or suggestions will be appreciated.
>> 
>> Doug H
>> 
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