[TowerTalk] Sprockets with 2" bore needed

[K8RI]

On 4/27/2012 5:15 PM, K1TTT wrote:
> I would find a chain that will handle the force plus safety factor then get
> a sprocket that is meant for it.  If the chain can handle it hopefully they
> have designed the sprocket to be better than the chain.  Don't just go with
> industrial suppliers, check automotive, motorcycle and atv parts suppliers
> also.

One thing that first entered my mind when I started this was the primary 
chain and sprockets for the Harleys.
Also look at the first two photos on 
http://www.rogerhalstead.com/ham_files/skyhook.htm. Unfortunately none 
of them show the chain clearly that thing is turning over a ton. It's 
turning roughtly a 100' of a straight, 3 3gged tower with 3" diameter 
legs plus the large arrays on it.  Photos, 5, 6, and 7. The thrust 
bearing is close to half a ton.

thanks,

Roger (K8RI)


>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
>
>
> -----Original Message-----
> From: K8RI [mailto:K8RI-on-TowerTalk at tm.net]
> Sent: Friday, April 27, 2012 21:00
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Sprockets with 2" bore needed
>
> On 4/27/2012 4:34 PM, Jim Hoge wrote:
>> Check McMaster- Carr. They list them but with a higher price tag. The
> manufacturer you want to search is Martin Sprocket and Gear. Any supplier of
> power transmission equipment ought to carry them. If you can tolerate a
> larger outside dimension then you can away from searching for only finished
> bore sprockets and go for bushing bore sprockets as well.
>
> I had e-mailed them earlier.  I just received a reply back stating they
> could not make a recommendation for my application which was:
> 2" ID/Bore, finished or machinable, OD of roughly 4" and a linear force on
> the chain of 500# which includes a safety factor.
> I know I've seen systems that ran far more force than this.
>
> Torque on the 2" shaft is roughly 1000 inch # at maximum wind gust. With an
> OD of 4" this is reduced to 500# which would translate to 500 linear #  on
> the chain.
> OTOH the small rotator can go to about 1500 in # so that would translate to
> 750 # of linear force on the chain.
>
> I have looked at the bushing bore sprockets, but not specked any out.
>
> 73
>
> Roger (K8RI)
>
>
>
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