# False crotch block



## Treecutr (Feb 16, 2010)

I am finally going to upgrade to a block and sling ( little extra money now ) I never looked at cost of block, wow, does it matter which style I get, or will either suffice. 
This style,View attachment 125578


Or this style and used with steel binerView attachment 125579


Or suggestions. I have the sling picked, thats an inexpensive investment


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## tree md (Feb 16, 2010)

I use the type on the top only mine is made by CMI. I haven't used the type on the bottom (for heavy rigging) so I can't comment on it.

You need to be careful if you have it set remotely that the lock is facing away from the tree and that it does not twist around to face the tree when doing multiple rigging operations. It can work loose if there is friction from rubbing against the tree. I had this happen to me one time when I was lowering multiple limbs from the same rigging point. Luckily I was close enough to my rigging point to check the block and noticed that it had started to come unscrewed. I always keep an eye on it now, especially when I am using a remote rigging point and make sure that it does not get twisted around and rub against the tree which could cause it to work loose.


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## flushcut (Feb 16, 2010)

*Blocks*

Use the top ones for the heavy stuff and the ones on the bottom for the light stuff. The blocks that you connect a sling directly to are much stronger and involve less gear to rig and have less fail points unlike the biner connect type. They both have uses in your arsenal of toys, redirects in your rigging, simple mechanical advantage setups, or connecting a block to chain/metal eye of some sort.


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## pdqdl (Feb 16, 2010)

I recently bought that exact pulley (the little red CMI) for lighter rigging, as I figured it would be much handier to move around in the tree.

*We damaged it in the first tree we put it in. *We were using it to carry speedline drops out of a locust tree for some of the heavier branches because we did not want to heat up the rope or 'biners with non-rolling friction on some of the larger branches. Attached to a loopie with a steel carabiner, the bends in the side plates straightened out and pinched the pulley. It was sliding down the speedline without rolling. The cheek plates were squeezed tight against the sheave.

Nothing we cut was more than 750 lbs, and the speedline was rigged pretty loose and stretchy to soften the blow. I was really disappointed that it quit working right, especially since the pulley had a higher rating than the loopies or the carabiner. They never seemed to even get nervous by the loading, but the pulley got damaged "out of service".

It's a nice little pulley, and I am sure it will not fail until the rated load. It will quit working correctly quite a bit sooner than 7k it is rated at.

We fixed it by taking it apart, hammering out the cheek plates, and replacing the axle with a grade 8 shoulder bolt. Lubed it, and it is back in service (light duty, of course).


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## mndlawn (Feb 16, 2010)

We have a couple of these, I like them.


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## tree md (Feb 16, 2010)

mndlawn said:


> We have a couple of these, I like them.



Hmm... I have the same block only mine has the lever to tighten the lock. Looks like they went to a twist knob. I wonder if it was because they had problems with them working loose when they got banged around. This is the type I have. Have been using these blocks for several years now. Haven't bought a new one in over two years:


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## RacerX (Feb 17, 2010)

The major difference between a block and a pulley is it's ability to withstand shock loading. Here's a good explanation from Wesspur.



> Choosing an Arborist Block or Pulley
> 
> There are dozens of pulleys and blocks available for the use of arborists today. However not all are created to the same specifications, and there are many applications which will put high demand on the hardware and for which only certain blocks should be used. While the terms "block" and "pulley" are largely interchangeable, we have divided them into two main groups for clarity:
> 
> ...


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## JeffL (Feb 17, 2010)

I have the same large steel CMI block like posted above. I like the handle on the screw, makes tightening/loosening a little nicer as opposed to those spring pins on the aluminum blocks.

Pulleys are not meant for heavy rigging, like you posted up at the top. Get a nice whoopie, a 5/8" bull rope and a good block for the heavy stuff.


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