[TowerTalk] More friction needed

[Steve Dyer W1SRD]

Kurt had the clamp spreading bolt from early on. I have one with it.
73,
Steve
W1SRD
> What Steve K7LXC omitted from his question regarding the M2 mast clamp and mast friction situation is the mast size, but Grant KZ1W made a great recommendation below to increase the contact area for variations in mast size.  My prop pitch M2 mast clamp was previously modified by K7NV as he had resurfaced the clamp teeth of the M2 mast clamp included with his rebuilt small prop pitch for handling my 2-7/8" outside diameter galvanized chrome-moly 22ft mast, but still recommended pinning the mast.   As the newer K7NV designed mast clamp and the DX Engineering modification of the K7NV clamp both are specified for either 2" or 3", how well would either 3" version capture and secure my 2-7/8" mast?  How much tolerance for using a smaller mast diameter is built into the design? The DX Engineering modification of the K7NV clamp design by adding one or two clamp spreading bolt(s) to assist spreading the clamp seems like a great idea.
>
> 73,
> Gary N0GS
>
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Tim Duffy
> Sent: Tuesday, November 08, 2022 8:02 PM
> To: 'Steve Dyer W1SRD' <w1srd at yahoo.com>; reflector -tower <towertalk at contesting.com>
> Subject: Re: [TowerTalk] More friction needed
>
> I have 5 tower tops using the K7NV clamp. Large antennas, one Yagi stack (big 40 and 10 meter beams) has 35 square feet of wind load at 260 feet! The K7NV clamps here have not slipped yet.
>
> 73
> Tim K3LR
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Steve Dyer W1SRD via TowerTalk
> Sent: Tuesday, November 8, 2022 8:42 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] More friction needed
>
> What would a competent machine shop charge to do this? Most of us don't have a fully outfitted machine shop :-).
> 73,
> Steve
> W1SRD
>> Bolt the two clamp sections to a lathe faceplate and bore them to the
>> mast diameter.  Remove enough material to enlarge the contact area and
>> insure the bore is true to the bases.  Use grade 8 bolts and use a
>> torque wrench to max spec torque for the size bolt.  Repeat this
>> tightening 3 times.
>>
>> The clamp bore as cast wasn't straight to the machined base and only a
>> few "points" would have made contact in the 2800 I have turning a 375#
>> 100ft tip to tip 2L 80m beam.  Now it doesn't slip.
>>
>> Grant KZ1W
>>
>> On 11/8/2022 10:00, k7lxc--- via TowerTalk 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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