Hmmm... interesting. 10 years ago, I had a swinging-gate side-mount
fabricated, and the guy used a piece of an ordinary cutting board (about
5/8" thick) for the top bearing. It's still there, still appears sound,
and not noticeably distorted by the side load. I had thought those
boards were made of HDPE, but who knows for sure?
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
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On 10/14/2011 5:46 PM, Stan Labinsky Jr. wrote:
> One thing to bear in mind, gents, is the effect that UV has on HDPE. I have
> a nice European (looking) low band Ringo style antenna which is shot because
> the HDPE sleeve which insulates the radiator from the mounting sleeve is
> cracked and split in multiple places, all courtesy of Mr. Sunshine.
>
> Stan
>
> ----- Original Message -----
> From: "Jim Lux"<jimlux@earthlink.net>
> To:<towertalk@contesting.com>
> Sent: Friday, October 14, 2011 10:46 AM
> Subject: Re: [TowerTalk] Thrust bearing thread
>
>
>> On 10/14/11 4:34 AM, w8zn@comcast.net wrote:
>>> It has been interesting seeing all the posts about this. The real
>>> question is why would you ever use a TB3 or TB4 at $161 and $185 (from
>>> 3Star) when you can have a REAL bearing for only $30.98???? Made with
>>> REAL steel, seals and a zerk fitting?
>>>
>>> Check out
>>> http://www.thebigbearingstore.com/servlet/the-88/2%22-Four-Bolt-Flange/Detail
>>>
>>> A nice 1" thick plate of Delrin with a two inch hole cut in it using a
>>> hole saw from your local hardware store works really well also - Delrin
>>> however is way more expensive than these bearings.
>>>
>> Delrin might even be overkill.. A couple slices from a 1/2" thick
>> cutting board (or a 1" thick board) made of HDPE (aka poor man's teflon)
>>
>>
>> Almost any plastics supplier can supply it. A quick google for HDPE
>> Cutting Board turns up, for example, US Plastics a 1/2"x12x18" sheet for
>> $11
>>
>> That acetal/Delrin is expensive.. $100 for a 1x12x12 chunk... Acetal is
>> nice to machine, though. It's a lot harder than PE and it doesn't melt
>> while you're machining it, but it's probably overkill for the radial
>> load bearing application.
>>
>> HDPE in 1x10x10 is $18, they also have UHMW PE, PVC, Nylon,
>> polypropylene, etc. They're all fairly inexpensive.
>>
>> McMaster Carr also has this kind of thing, and really, really fast
>> delivery, if you want to get working on it tomorrow.
>>
>> For the impecunious among us, checking with restaurants who are throwing
>> them away could probably get one for free. (They have to dispose of
>> them when the cuts and scratches get too deep to be properly
>> sterilized). The cafeteria at work probably has 200 of these boards in
>> various colors stacked up in the kitchen.
>>
>> _______________________________________________
>>
>>
>>
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