snatch block

[Jim Martin]

I get trees stuck up from time to time and would like to pull them down  with a winch or come-along.  I want to change the direction of the pull with a pulley or better with a snatch block.  Beats pulling a tree down on my head. I assume I need a 5/8 inch rope, to be attached to the  wire rope on my winch.

There are very big, heavy expensive snatch blocks on the market and simpler, lighter,  cheaper ones.

Where can I buy one strong enough, big enough, and cheap enough for my needs?

[Peter Smallidge]

Hi Jim:

I bought a heavy and rather expensive (a few hundred $$) a few years ago, and it works really well.  http://www.farmiwinch.com/Accessories/  from this dealer http://www.northeastimplement.com/ (not endorsements, just information).  

Strong enough, big enough, and cheap enough for you are hard to judge for me.  An injury to you or a friend helping you isn't worth $400 (or whatever, I don't recall the price).  You can get non-self releasing snatch pulleys at hardware stores, but I don't know what their weight capacity is.  As a point of reference, you are pulling a tree that might weigh 1000 or more pounds.  A quick search suggested a 20" dbh tree would weight 7000 lbs.  I would be very cautious of

1. rope or cable strength
2. pulley strength
3. standing "inside" the "V" formed by the pulley

I will attach a file that estimates the volume in cords of a tree of a given diameter,  A cord of wood is 2 to 2.5 tons green.  You can calculate the approximate weight of the tree based on the attached file and the cord to weight conversion. Then add any resistance since the tree is stuck.

I have had good luck with synthetic kevlar rope http://www.amsteelblue.com/Index.aspx (the 5/16 line has 13,700 lbs capacity).  I have used this on the Cornell and also on my personal arch for several years without any glitches.  Light and tough.

Maybe you and some other local woodlot owners could co-own a nice self-releasing snatch block.

Good luck,

Peter

[John McNerney]

I bought a second self-releasing snatch block a couple of years ago.  It was very similar in design to the Farmi block Peter mentioned, but it cost me about half the price of the Farmi and Norse blocks that I've seen advertised. It was made by a guy who runs a machine shop and needed one for his own use.  He ran up a few extras to sell. These things are built like a tank.

If anyone is interested, send me a message or email and I'll see if I can dig up the source again.

I have no connection to the manufacturer other than that of a satisfied customer.

John McNerney

[Peter Smallidge]

Hi John:

If you could share information on the source with this site, that would be a great resource.  Thanks for the reply!

Peter

[John McNerney]

Still waiting for him to get back to me with price and availability. I'll post something as soon as I get it

[Jim Martin]

I bought a swing side snatchbloch on Ebay for $24.  Rated about 10 000 lbs, used with 3/4 rope.

I have pulled down three leaners; it worked just as it is supposed to.

[John McNerney]

Jim- Is a swing side snatchblock one that requires manually releasing the cable?  They are generally far less expensive than the self-releasing snatchblocks, since the pulley is supported on both sides when under load. A self-releasing snatchblock supports the pulley on only one side, so it needs to be quite a bit beefier.

A self-releasing snatchblock is used when you want to winch in some logs, but need to pull them around a corner.  You pull the log up to the block, then the block automatically releases the cable.

Here's a link to a self-releasing snatch block in action. Skip up to about the 1:30 mark in the video to see them using the snatch block to pull the logs around a corner. (Peter, I hope it's OK to post a link to a commercial site here.  I'm not trying to promote this specific vendor, this was just the only video I could think of off the top of my head.) Here's another snatch block video, not as close up. The log releases at about the 0:08 second mark.

Jim, I'm guessing this is overkill for what you needed.

[John McNerney]

I still haven't heard the current price from the guy who is making the self-releasing snatch blocks, but here is a thread on the Forestry Forum where he is offering them for sale:

Self Releasing Snatch Blocks

This is not a stock item for him. He makes a batch up whenever he gets enough interest. He sold out of the original batch, but is getting close to making up more.

Here's a picture of what he makes (his is the one on the left):

Here's another shot. You can use the strap, as shown, or install the keyhole for use with a chain. On mine, the pulley wheel was zinc plated, rather than the older style yellow coating shown here. He's also switching form powder-coating to painting (either one gets dinged up in use, so he figured not much point in the extra expense of powder coating).

[John McNerney]

The order taking for the self releasing snatch blocks shown above is now going on.  If the link does not work for some reason, go to www.forestryforum.com, go to the For Sale section, and look for the thread entitled "Self Releasing Snatch Blocks"

I'm still not sure of the price, but it should be well under what they sell for elsewhere. (mine was about half price when I bought it a couple of years ago).

John McNerney

[Jim Martin]

Thanks John.  As I wrote previously I am using a swing-side snatchblock which fulfills my needs perfectly.  No need for overkill as you put it.  I am pulling down leaners not logging.

[John McNerney]

I figured you were all set, but Peter asked me to post the link for the self releasing snatch block. 

I'm not a logger by profession.. I do my own firewood harvesting, help out some friends, and occasionally donate some firewood to families in need in my area.  I've got a compact tractor with a logging winch  The snatch block has really increased my productivity, and allowed me to get logs out of the forest without barking up the trees still standing.