Re: [T3] Horn mechanism repair. What size screw?

[Chris Slaymaker <nurofiz@knology.net>]

I got helicoils from McMaster/Carr, but I apparently got the wrong size tap.
The catalog was no help (I also got the wrong size drill bit).

The helicoils are M3 x 0.5

Unfortunately, the tap is ALSO M3 x 0.5  ($17.90 mistake).

The helicoil package says that a 1/8" drill bit is required.

Assuming the M3 x 0.5 is the right size helicoil, what size tap do I need?

Your guess was right, Jim.  The lock washers were missing and the only way
to keep the horn from blaring is (was) to back those screws out a little.

On 6/8/07 10:27 PM, "Jim Adney" <jadney@vwtype3.org> wrote:

> On 8 Jun 2007 at 18:39, Chris Slaymaker wrote:
> 
>> The three screws that hold the horn contact on have wallowed out of their
>> holes.  How can I get them to seat back in?  I have considered JB Weld.  I
>> don't think they make Helicoils that small.  I have thought of winding fine
>> wire around the screw.  Also filling in the hole, drilling and tapping.
> 
> You're asking about the ones in the steering wheel, right?
> 
> I'm sure they do make Heli-Coils this small. That would be the best
> repair, but it's probably more expensive than you'd like. Filling
> with JB Weld is probably a reasonable thing to do, but you'd want to
> make sure you are set up to drill and tap carefully in exactly the
> right places and perpendicular to the wheel. If you screw it up,
> you'll never get it right again.
> 
> I'm gonna guess that they wallowed out because the PO left them
> loose, and he left them loose because if he tightened them then the
> horn was on all the time. If so, this is because someone took this
> apart and lost one or more of the little internal star lockwashers
> that are supposed to go between the shoulder of the screw and the
> steering wheel. The thickness of this washer makes all the difference
> in the world, and these washers are often left out. You can replace
> them with a standard US #6 internal star washer.

-- 
Chris Slaymaker
'71 Westfalia - "Lurch"
'71 Squareback - "Foster"
Knoxville, TN

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