[C320-list] Mast thickness

[P.F. Ross]

Scott,

Was able to measure my replacement mast gate screws today.  I used 10-32 SS
button head cap screws.

I used a lubricated #21 tap drill (.159) but a 5/32 (.156) would also
work.  When tapping in spars, I like to chuck the tap in a variable speed
drill and proceed slowly at low rpm, much easier to keep tap square rather
than using a handle.  I also use "Tap Magic" Aluminum cutting fluid while
tapping.

And as others have noted, I use "Tef Gel" on the threads when installing
screws to help prevent corrosion.  Did this 25 years ago and all is well.
I am able to snug screws down tightly and have not come close to stripping
them.

I also posted a pic of the smooth button head profile on the gate in my
owners gallery album online.

Regards,

Frank Ross
Beta Wave #206

On Sun, May 14, 2023 at 6:33 AM Bill & Kay- Diversion via C320-list <
c320-list at lists.catalina320.com> wrote:

> Tefgel to prevent SS-aluminum corrosion. Lifetime supply on Amazon for $36:
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> -----Original Message-----
> From: Greg Flanagan via C320-list <c320-list at lists.catalina320.com>
> To: C320-List at catalina320.com
> Cc: Greg Flanagan <greg.flanagan at shaw.ca>
> Sent: Sat, May 13, 2023 7:26 pm
> Subject: Re: [C320-list] Mast thickness
>
> Yes, thank you.
>
> PS the machine bolts I used on the plate were machine head (round) not
> knurled, so they need a screw driver. We use Roberts heads here in Canada
> as they don’t strip out like slot or Phillips. However, a hex head would
> also be good. I don’t take the plate off. I just loosen it and it gives an
> opening where the glides can slip in.
>
> Greg
> Hoop Dancer #1076
> Sidney, BC
>
> > On May 13, 2023, at 4:10 PM, Dave Hupe via C320-list <
> c320-list at lists.catalina320.com> wrote:
> >
> > Greg-
> > Probably Lanocote grease for use between different metals?
> > Dave Hupe 1994 C320 #32
> >
> > Sent from Yahoo Mail on Android
> >
> > On Sat, May 13, 2023 at 6:56 PM, Greg Flanagan via C320-list<
> c320-list at lists.catalina320.com> wrote: I had the same problem. I got a
> drill bit and tap the next size up. Redrill the hole which will not
> generate much metal as the next size is about the size of the old tap. The
> thickness is  only about 3/8” so one needs to tap carefully maintaining a
> strict perpendicular approach. Aluminum is easy to tap but still use oil
> while doing this. I went with a fine thread. The cause of the initial
> problem is a SS machine bolt going into aluminum. The dissimilar metals
> rots the metal. A friend gave a grease like material (help needed on what
> this is) to coat the new bolts with before I reassembled the plate. It is
> now over 10 years and all is well (even better).
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> > Greg
> > Hoop Dancer #1076
> > Sidney, BC
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