i couldn't pull up the CMI site this mourn; but i believe the 'single' pulley is only made/sold in this size for special purpose stuff. That there is not much reason not to get the drop eye/double ended pulley (w/~5% more friction); except for special needs. About the same weight and size in the 2 models (drop eye or not).
i think CMI only makes the single pulley in this size with the bearings as a specialty option; and also some aluminum (stenght drop)cheekplate models for smaller size and weight as a specialty concern. The utility of the extra eye for a line or another pulley is too much 'goody' to have ready, not to take it along instead of a single, save for special interest. There are more expensive drop eye w/bearing$ available i think (CMI).
In simple, redirect lowering/holding, the slightly reduced efficiency of the bushing, actually would help reduce line load minutely, thereby minutely (compared to more expensive bearings) lower support load, per non lifting position. Also lowering is more likely for it to take a shocking, bearings don't take this as well as bushings, and further could mark the axle that they ride on, accelerating wear, decreasing that last 5% efficiency you paid for too. The sliding sleeve of a bushing spreads out stress better to the axle, and is less persnickity about imperfections in the axle; as 2 seperate positives, IMLHO.
i only thought that Sherrill sold the bearing pulley for compression and lifting jig type uses, made it a single to keep the alike looking CMI pulleys (same cheek plates) seperated in bushing/bearing divisions. That is where the inefficiency of the bushing would be against you, not for you. And each occurance of the less efficient bushing in the 5x1 lifting/compression jig etc., would compound/multiply against your efforts to lift (just as if lowering/holding they would multiply there inefficiencies together to help fight gravity).
Sherrill used to sell a 2" wide rescue pulley aluminum (mine grew legs....) but not a CMI. i wish they would again, as it could tuck under another pulley on the drop eye/double pulley chained together, and not let the lines rub in compounding jig lifts; kinda like a modular fiddle block assembley slapped together with rescue pulleys.
Seeing as there is only so much energy in a system, each system can have an energy crisis, the bearings addresses this at a price besides dollars IMLHO.
So git the 'double pulley' fer less if you are in the market, and understand JP's warning
:alien:
i think CMI only makes the single pulley in this size with the bearings as a specialty option; and also some aluminum (stenght drop)cheekplate models for smaller size and weight as a specialty concern. The utility of the extra eye for a line or another pulley is too much 'goody' to have ready, not to take it along instead of a single, save for special interest. There are more expensive drop eye w/bearing$ available i think (CMI).
In simple, redirect lowering/holding, the slightly reduced efficiency of the bushing, actually would help reduce line load minutely, thereby minutely (compared to more expensive bearings) lower support load, per non lifting position. Also lowering is more likely for it to take a shocking, bearings don't take this as well as bushings, and further could mark the axle that they ride on, accelerating wear, decreasing that last 5% efficiency you paid for too. The sliding sleeve of a bushing spreads out stress better to the axle, and is less persnickity about imperfections in the axle; as 2 seperate positives, IMLHO.
i only thought that Sherrill sold the bearing pulley for compression and lifting jig type uses, made it a single to keep the alike looking CMI pulleys (same cheek plates) seperated in bushing/bearing divisions. That is where the inefficiency of the bushing would be against you, not for you. And each occurance of the less efficient bushing in the 5x1 lifting/compression jig etc., would compound/multiply against your efforts to lift (just as if lowering/holding they would multiply there inefficiencies together to help fight gravity).
Sherrill used to sell a 2" wide rescue pulley aluminum (mine grew legs....) but not a CMI. i wish they would again, as it could tuck under another pulley on the drop eye/double pulley chained together, and not let the lines rub in compounding jig lifts; kinda like a modular fiddle block assembley slapped together with rescue pulleys.
Seeing as there is only so much energy in a system, each system can have an energy crisis, the bearings addresses this at a price besides dollars IMLHO.
So git the 'double pulley' fer less if you are in the market, and understand JP's warning :alien:
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