Re: [Harp-L] Welding reeds (was Reed slot needs to be shortened)

["Doug H" <dough.harpl@xxxxxxxxx>]

Hi Vern,

Regarding shortening the reed slots on my custom reed plates I have yielded to the 'easy' approach of simply installing a longer reed with the same pitch (easily available since CX-12 reedsets come in all keys).  It is my nature to try and have things go according to plan, but for these eight prototypes I'm going to make an exception.  My perfectionist instincts can be real time eaters if I don't rein them in.

I sure do thank you though for your helpful advice, onlist and off.  

Your method of welding the brass reeds takes the cake in the amazing category, especially as a DIY project.  At some point, I for one would like to see some photos and get more technical details.  

One of the upsides of welding reeds is (I think) that it easy for manufacturers to automate an aligning and welding process, compared to riveting or screwing.  The need for having holes in the plates and reeds is also eliminated.  A downside is that if or when the reed fails, most technicians will have to drill and use a screw.  But if there were a welding rig available for the typical technician it might encourage more manufacturers to weld on reeds.  . . . Just a thought.

Doug H


----- Original Message ----- 
  From: Vern 
  To: Doug H 
  Cc: Harp L Harp L 
  Sent: Sunday, November 07, 2010 11:42 PM
  Subject: Re: [Harp-L] Reed slot needs to be shortened


  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
  > 
  > On Oct 29, 2010, at 10:56 PM, Doug H wrote:
  > 
  >> 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
  >> 
  >