[CAUT] Polishing Agraffes ... enjoying the discussion!

Mccoy, Alan amccoy at ewu.edu
Wed Sep 30 15:21:35 MDT 2009


Here's what I use for reshaping the hole.[cid:3337165295_1059357]
Combined Countersink - Drills Type: Radius Type Included Angle°: 60 Drill Size: 1.60 mm Overall Length: 35.50 mm Drill Length: 4.25 mm Body Diameter: 4.000 mm Material: HSS
This can be found at MSC on page 189 (Titus), MSC part number 01032259. Note the smooth radius as opposed to the standard countersink with the abrupt angle change. The one at Pianotek used to be the standard countersink unless they have changed to this smooth radius countersink. About $10.

This is what I use for polishing after shaping. [cid:3337165295_1062122]

3/16 inch x 5/8 inch Pink Final Polish Silicon Softies Flame Polisher, 3/32 inch Shank. Made in Germany. For use with Dremel Rotary Tools.
This can be found at widgetsupply.com under Dremel/polishing/rubber-flame. About $15 for 10 of them.

These tools work for me whether for new parts or old ones. In a pinch they can be used for agraffes still in the piano, but in that case on the distal side only. I really prefer to use the countersink chucked in a variable-speed drill, approaching each hole while the drill is running slowly. I set the variable speed stop so it cannot speed up beyond the speed I want. I get less chatter and less tendency for digging into the agraffe this way.

Your results may vary.

Alan McCoy


________________________________
From: <PAULREVENKOJONES at aol.com>
Reply-To: CAUTlist <caut at ptg.org>
Date: Fri, 25 Sep 2009 10:20:50 -0700
To: CAUTlist <caut at ptg.org>
Subject: Re: [CAUT] Polishing Agraffes ... enjoying the discussion!

To be honest, Jim, abrasive cord is the first thing I ever used, and, based on that, now the last I would ever recommend. It truly tears up the inside contact surface of the agraffe. It might work for a quickie fix-up, but I would never use it on a fine instrument of any kind. Just my experience.

P

In a message dated 9/25/2009 12:01:14 P.M. Central Daylight Time, jim_busby at byu.edu writes:



Stan,



I'm  grinning because today I used abrasive cord (1000 grit I special ordered) on  an L I'm restringing. I simply didn't want to take out the agraffes. But if I  take them out, I do the Q-tip thingee.

JB






From:  caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Stan  Kroeker
Sent: Friday, September 25, 2009 8:18 AM
To:  College and University Technicians
Subject: Re: [CAUT] Polishing  Agraffes ... enjoying the discussion!



Hi all,







This discussion reminds me how taking care of the plethora  of small details results in a big difference in the final  product.  We have the freedom to do these things, don't  we?







I recall heated discussions in past about fitting pinblocks  to plate flanges.  How close is close enough? 0.020"? ... 0.010"?   How about contact along the entire length of the flange (or at  least once every inch)?  Whether you believe the block can or can not  move once it's securely screwed to the plate web, by achieving a full-fit you  have forever eliminated movement as a potential cause of tuning  instability.







Re:  agraffe servicing







I neglected to mention that I'm not sure yet whether I  prefer the use of hourglass-shaped reamers or abrasive cord to remove burrs  from old agraffes or re-profile new ones (I have both).  I keep coming  back to the abrasive cord for its simplicity and minimal risk.  You see  immediately (by 'shoe-shining' the holes) that you are removing metal but it's  hard to overdo it.  Another advantage of the abrasive cord is that, after  machine polishing, the cord effectively cleans out any residual compound from  the recess.  With this method, I don't bother polishing the  holes/recesses.  Simply a case of diminishing  returns.







Thanks again to all for your contributions on this  subject!







Regards,







Stan Kroeker, RPT

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