Lewmar, Harken, Schafer, & Ronstan are the serious makers of quality
sailboat blocks. I use ball bearing blocks (polymer balls) for most all
applications as the efficiency gain and wear reduction is enormous.
Stainless steel has lost out to polymers except for wire rope blocks.
Plus my go to is dacron, polyester, even Kevlar low stretch lines, New
England Ropes among the best or Synthetic Textiles dacron. Nylon is
good when you want 30% stretch, and is exciting for suspended loads.
NEVER for guys.
The smallest blocks go for for under $20 or so, 400#+ working load,
cheaper when you shop around other than West Marine. MauriPro Sailing,
Fisherman's Supply and several others.
https://www.mauriprosailing.com/us/product/LEW29901321BK.html
Sailing snatch blocks are more than capable of any antenna weights, but
are a bit pricey. 4" is huge by sailing standards - why? A 3" has a
SWL of a ton.
Other rated snatch (not quick connect) blocks are used in technical
climbing and arborist work, plenty of capacity. Check REI or an
arborist supplier. Nice because they have short attachments, usually to
a shackle.
The cast iron Chinese blocks might be rated a few zillion pounds, but do
you believe it? Huge friction losses too.
Grant KZ1W
On 3/9/2021 14:12, Dave Sublette wrote:
Greetings fellow tower dwellers,
I need to replace pulleys used to haul up 80 meter dipole ends. I need to
find sources for good quality pulleys, perhaps stainless steel types used
on sailboats?
I also need a general purpose, 4 inch diameter pulley for hoisting antennas
(big) on the tower. Perhaps this one should be the snatch block variety?
So what are your go-to sources? Google always returns plenty of hits.
Knowing who the good suppliers are and the quality of goods is very
important and hard to judge from advertising info.
Thanks and 73,
Dave, K4TO
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