block maintenance

L

Leon

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rambling
I have a couple of the cheap Sherrill 2 ton blocks (with bushings) that have recently started making loud squeaking noises when in use. Is there a specific lubricant that I should use to make them run quietly again?

thanks
 
speaking of blocks, what do you guys recommend for a heavier duty rigging block, for BIG pieces?? brand, load etc...?

jp
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those bushings are oil impregnated brass, they should not need lubricant. if they are squeaking there is a problem.

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I had a feeling that might be the case. I can't really figure out what could have happened though, because all I have used these blocks for recently is lifting/pulling with the GRCS, no shock loading.

There is no manufacturer's stamp on them, so I'll call Sherrill tomorrow and see what they say.
 
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speaking of blocks, what do you guys recommend for a heavier duty rigging block, for BIG pieces?? brand, load etc...?

jp
grin.gif


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JP Try ISC (the big yellow ones) blocks, I like their functionability. they are easy to use in the tree

Rob
 
I like the CMI arborist blocks. Stainless steel construction and oil impregated bushing for the sheave with a bushing for the eye sling. They come in 5/8" and 3/4". The eye sling bushing is now captured in case I get the dropsies.
 
Leon, I have a few of those blocks as well, one of them has nearly locked up. It gets put on spars/trees that need to have a pulley in the tree for added MA. If it gets buggered I wont cry.

Let us know what Sherrill says.


I do like my ISC springblocks, you get what you pay for!
 
I just spoke with a fellow at Sherrill who recommended dry graphite to lubricate the bushing. He did not feel that the squeakiness alone indicates any loss of strength in the block.

I think I'll be ordering some new ISC blocks, anyways.
 
Leon,

Do the sheaves spin free? Is there any hang-up?

A good machine shop could ream the bushing to bring it back into round. A reamer will only take off a shaving and shouldn't effect the function of the works.

Are the cheeks of the sheave rubbing on the side plates of the block?
 
If there is squeaking there will be metal smearing as well. Look for it and where found, take some Scotch-Brite to the surfaces to clean them up before lubricating them. If it's the center of the oil-impregnated bushing clean it and soak it in some lightweight oil for a while. The oil in such a bushing will eventually evaporate, get washed out, or just plain used up, requiring replenishment over time. Not a big or painful deal.
 
Thanks Glen, that sounds like good advice.

Tom, the sheaves are not rubbing against the cheek plates. Taking the block to a machine shop would probably cost as much as the original price of the block. I would rather buy a replacement than do that.
 
metal bushings use up their impregnated oil after awhile. When the pulley is turning under load, it heats up the bushing. This will cause the very tiny amount of oil to eventually evaporate, hence the squeaking (there is a reason sealed bearing pulleys are superior).

Very common, nothing to worry about, eventually happens to EVERY bushing equipped pulley. Oil impregnated bushings are not some magical device that needs no maintenance......eventually they need to be relubed... Just dissasemble, clean the bushing with brake cleaner, and relubricate every so often. takes 5 minutes. not a big deal at all, no maching or replacement required. I have two bushing rescue pulleys, they get stripped 2 times a month and relubed, good as new.

using a full synthetic grease (TRIFLOW, REDLINE, AERONAUT or synthetic oil will prolong the maintenance regime. If you really want to lubricate the bushing, use MILITEC.
 
Ha! Maybe they're just complaining to me Frans: "It's not the heat that gets you, so much as the HUMIDITY!", but all I hear is squeaking.

Seriously, though, I don't know what kind of effect different humidity levels would have on equipment like this. Working in a rainforest, my gear does spend a lot of time in the humidity, if not just being downright soggy, and I'm sure this does contribute to more rapid deterioration of some types of gear. I'm not sure about the metal hardware, though.

Thanks for all the advice folks. I'll strip, clean, and relube both blocks. And just cause my boss said I could I'll order a nice new ISC Springlock Block too!


SRTTech, I hear awesome things about Militec, but that stuff is EXPENSIVE.
 
[ QUOTE ]
speaking of blocks, what do you guys recommend for a heavier duty rigging block, for BIG pieces?? brand, load etc...?

jp
grin.gif


[/ QUOTE ]

Hobbs are very strong, efficient and easy to strip and lube. Sierra moreno merc. informed me the largest stalled the yale test bed at 40,000lbs, and only distorted, not loose the load. The ISC blocks are convenient but not straight forward to lube. Last time I spoke with Denny about it, he suggested soaking in light oil. But I've never had a squeeky ISC block. I have had a squeeky Hobbs, but that is easily remedied by strip and clean and lube. There are two yellow ISC blocks. The largest is rated for 40,000lbs tensile also. All the rest are rated at 20,000lbs tensile. WLL are figured on a 5:1 SF.

I use both blocks daily. Just be careful with springlocks - be wary of the proud knurled knob being activated as the block turns against the stem when being loaded; I've had them turn open before I was wise to how easy it can be. I've also noted the small allen bolts that hold the Hobbs sheaves can work loose. Just a question of routine maintenance and pre-use checks, like all pros do as a matter of course.

Like I said, I love them both - just some insight on what I've found whilst using them (we have a very wet = dirty climate - harsh conditions at times for any block).
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Thanks for all the advice folks. I'll strip, clean, and relube both blocks.

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Just for clarification Leon-They mean for you to disassemble the blocks for cleaning and relubrication.-You can remained clothed throughout the procedure.
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