K7NV makes the same observation on his web page, Dick, and suggests that
if you want to pin a mast the hole needs to be drilled very precisely
and a pin specifically designed for this purpose be used, rather than a
bolt.
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000
On 4/5/2012 2:21 PM, Dick Dievendorff wrote:
> Someone suggested to me that I might increase the mast to clamp friction by
> wrapping the mast with something with a little bite. Do they make
> double-sided emery paper that can tolerate being wet?
>
> I have a clamp to mast size mismatch that I'm going to try to correct with
> shims, and I might end up pinning too. My prop pitch doesn't have a wedge
> to break.
>
> I've used pins (usually grade 8 bolts) in the past and they have failed
> because they weren't hefty enough. The hole ended up larger than the pinning
> bolt and the wind would work it back and forth enough that it eventually
> fatigued and failed. The hole got larger in this process.
>
> I think I had too much on the mast. I've changed that in my new
> installation.
>
> Dick, K6KR
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Frank
> Sent: Thursday, April 05, 2012 5:24 AM
> To: n8de@thepoint.net
> Cc: KA9S - Jeff; towertalk@contesting.com
> Subject: Re: [TowerTalk] HAM IV rotor / mast slipping
>
> n8de@thepoint.net wrote:
>
>> The Tailtwister (big brother of the Ham IV) has a pre-drilled hole
>> through the upper rotor housing and clamp piece.
>>
>> I'd pin the mast with your rotor, just as is done with the T2X.
>>
>> 73
>> Don
>> N8DE
>>
>>
> Pinning the mast to the rotator is a sure way of preventing mast slippage.
> It also puts you at risk for rotor destruction if the wind load becomes
> overly excessive. Since there is no good way of predicting how strong the
> wind is going to be here in Texas, I have preferred not to pin the mast to
> the rotor (anymore).
>
> It is a PIA to have to re-align the directional calibration every so often,
> but it is an even bigger PIA to replace the rotor after its gears get
> striped.
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|