[CAUT] Aluminum hammer rail (Screw hole) repair

[Don Mannino]

Mark,
 
A couple of other repairs that work well if the hole isn't too far gone
. . .
 
1. Oversized screws are available from Yamaha - or at least, they used
to have them.  I haven't checked recently :-)
 
2. Swedging the hole works very well in many cases.  I use a fine
screwdriver with a sharp tip, position it at the edge of the hole and
tap with a small hammer until you have a mark in the aluminum.  Repeat
in a star pattern around the hole on all sides, so that you end up with
8 little lines radiating out from the hole.  The original screw should
tighten normally now.
 
In extreme cases I have turned the rail over and repeated the swedging
on the bottom as well.
 
Really, the hole would need to be really, really badly damaged to
require a threaded insert, but I can see that happening.
 
Don Mannino


  _____  

	From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On
Behalf Of Mark Cramer
	Sent: Wednesday, June 27, 2007 9:34 AM
	To: College and University Technicians
	Subject: Re: [CAUT] Aluminum hammer rail (Screw hole) repair
	
	
	How timely Barbara and Jim, I'm just traveling a new set of
S/F's on a 1976 C-7 and found a stripped hole in the bass.
	 
	Can you suggest a place to look for this kit... auto supplies,
etc? Does it have a parts number, or go by the thread size?
	 
	Otherwise, I seem to recall someone suggesting there was a
nominal upsize thread (imperial or metric?) that could be used.
	 
	thanks,
	Mark Cramer
	Brandon University
	 
	PS The alignment groove in the aftermarket parts I'm using
doesn't quite line up with the wire Yamaha recesses into their action
rails. This pulls the flange away from the lip that the flanges butt
against, making it difficult to get a nice alignment.
	 
	Fortunately, there's a recess in that lip, and I was ABEL to
thread a peice of #16 music wire between and the flange. Now I'm left
with about a .25mm gap between the lip and the flange, but at least it's
precise.
	 
	     
	 

		-----Original Message-----
		From: caut-bounces at ptg.org
[mailto:caut-bounces at ptg.org]On Behalf Of Barbara Richmond
		Sent: Wednesday, June 27, 2007 10:34 AM
		To: College and University Technicians
		Subject: Re: [CAUT] Aluminum hammer rail (Screw hole)
repair
		
		
		Hi Jim,
		 
		I bought the Recoil kit, but it has no screws in it.
What screws did you use?  
		 
		John Dewey also mentioned this repair in his class,
Action Frame Diagnosis and Repair, so, if it is OK with you, I will also
list him on the submission since I am putting together a special "TT&T
goes to the convention."
		 
		Thanks,
		 
		Barbara

			----- Original Message ----- 
			From: Jim Busby <mailto:jim_busby at byu.edu>  
			To: College and University Technicians
<mailto:caut at ptg.org>  
			Sent: Thursday, January 25, 2007 3:58 PM
			Subject: [CAUT] Aluminum hammer rail (Screw
hole) repair
			
			

			List,

			 

			Here's a way to repair stripped screw holes
(Especially if an oversized screw strips) in an aluminum rail that takes
less than a minute or two. "Helicoils" is what they are called. (See
attached pic.) 

			 

			You drill out the hole and tap it, then insert
the little coil which disappears into the tapped threads, and then
you're good to go! Maybe this has been shown on CAUT before, I don't
remember seeing it. The new screw is actually a machine screw with fine
threads so it takes a few more rotations, but this is way better than
anything else I've ever tried. The package shows a bolt, but what
actually goes in has a Phillips head and looks like a normal screw.

			 

			Jim Busby RPT

			BYU

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