I have one of the K7NV clamps, which is on my K7NV prop-pitch.
I agree that Kurt's passing was a great loss to us, but as far as this
clamp is concerned, it is possibly "too brilliant ... by half". The
trouble
is that the target mast must be:
1. Perfectly smooth.
2. Have excellent "circularity", as opposed to "eccentricity".
3. Have a diameter very close to 2.000 inches.
or else it may only sort of work, but not as well as you might think.
There is a certain amount of "luck" in meeting these requirements.
Then there is "physics":
Static Friction (IE "stiction") is a function of total clamping
pressure, period. Having a lot of area doesn't help. In defense
of the K7NV clamp, it is designed to have multiple clamping bolts,
so we can count the combined clamping pressure of the N bolts.
More physics: read up on cylinder head bolt design and the need
for the head bolts to be elastic. Inelastic U-clamp bolts deform
the clamp instead of stretching.
If your K7NV clamp works really well, then I am happy for
you ... that you were lucky, or maybe you tightened it with a
24 inch breaker bar.
I will also say that it is way better than the M2 clamp (also own
one of those).
---
Rick Karlquist
N6RK
On 2022-11-08 13:46, john@kk9a.com wrote:
> I don't think adding a friction material will help. There are better mast
> clamp designs out there. K7NV(sk) came up with a brilliant idea of clamping
> a round mast using a round clamp (imagine that). I thought that you also
> manufactured a replacement clamp that used u-bolts which could be properly
> tightened and remain tight.
>
> John KK9A
>
> k7lxc wrote:
>
> Howdy, TowerTalkians -
> I need more friction between an M2 mast clamp and the mast. How could I
> do that? What materials would work? Tnx. Cheers,Steve K7LXCCell:
> 206-890-4188
>
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