releasing snatch block ?

[woodman52]

A question about self-releasing snatch blocks. I have the tools/equipment (metal lathe, welders, torches etc.) to build myself some self-releasing snatch blocks. I have looked at photos of a lot of different ones and have a pretty good idea of how to go about it. My one question at this point is concerning the bar that holds the cable in position until the slider hits it and knocks it to the side. How is that held in place over the pulley? It seems like the cable could move it as you tighten up. It has to be tight enough to stay in place until hit, but loose enough to put back in place for the next pull. I have not seen any photos that show how this is done.

[beenthere]

Have you found the photo's that have been posted on this forum?

Post what you have found in your gallery so we have something to respond to in this thread. Might be able to better help you.

Jeff, owner of this Forestry Forum, may have some helpful suggestions. 
https://forestryforum.com/board/index.php?topic=45802.msg659213#msg659213
 

[g_man]

On mine there are two holes in the base and the swinging release bar has two rounded pins on the bottom side that align with the holes. The swinging bar is held on with a bolt and castle nut thru a spring so it forms an adjustable detent when the bar is centered.




 


That bar only holds the cable when it is slack, when there is tension the groove in the sheave holds it. The slider or hook comes up into the groove, pushes the bar open, and then pries/peels the cable up out of the groove.

Make it so that your cable can't get under the sheave and jam. The reason I have that picture is because I added that short section of curved rod so that my cable could not get under and jam.




 




gg

[woodman52]

On mine there are two holes in the base and the swinging release bar has two rounded pins on the bottom side that align with the holes. The swinging bar is held on with a bolt and castle nut thru a spring so it forms an adjustable detent when the bar is centered.




 


That bar only holds the cable when it is slack, when there is tension the groove in the sheave holds it. The slider or hook comes up into the groove, pushes the bar open, and then pries/peels the cable up out of the groove.

Make it so that your cable can't get under the sheave and jam. The reason I have that picture is because I added that short section of curved rod so that my cable could not get under and jam.




 




gg

Thank you that is exactly what I was looking for.

[Joe Hillmann]

Before you build a bunch of them you should build and test one.  I built two of them and found that even though they work well I have much less use for them then I thought I would.  I would much rather have two more regular snatch blocks than have two self releasing ones.

[woodman52]

Before you build a bunch of them you should build and test one.  I built two of them and found that even though they work well I have much less use for them then I thought I would.  I would much rather have two more regular snatch blocks than have two self releasing ones.

If they work well, why would you rather have regular ones instead? It seems like the self-releasing blocks would not be any more difficult to set up. I already have 3 regular snatch blocks, although one is so big, I don't use it. I currently carry two on my winch. Most of the time if I need one - all I need is one but sometimes 2 come in handy. I am currently doing a TSI and think a self-releasing one would save a lot of walking. I figure if I am going to build one, I may as well build two. Or at least turn 2 pulleys at once to save the setup time. I figure it would be a good project for when the weather is too bad to get out into the woods. If I had a wireless remote for my winch, I don't think I would bother but I not going to buy another winch so this might be the best option for now.

[Joe Hillmann]

Self releasing blocks are great for changing pull direction when you have room.

Often I dont have room to turn the log in a single turn when pulling out long logs.

When used to double up rope to increase power they are more prone to tangle than regular snatch blocks.

So for the type of work I do in  the woods and my small equipment self releasing snatch blocks arent as useful as I expected them to be.

[Joe Hillmann]

I also try to avoid long pulls because I often have to walk back and forth between the winch and log several times when the log gets hung up on other trees/stumps/roots or  it starts digging into the dirt.  Clearing a snag often requires releasing all tension on the cable.  When the the tension is fully released I need to check to make sure the cable is still fully seated in the self releasing snatch block.  I dont need to check the regular ones.

[g_man]

I use my self release block as my go-to snatch block weather I need release or not. It is easier and faster to hang than my standard block which I keep in the tool box as a seldom needed second and I don't have trouble with it dropping the cable or tangling.




 




 


gg

[dougtrr2]

In my small woods the self releasing snatch block is a godsend.  There are times when two would be nice, but I just can't justify it for the amount I use it.  As g_man mentioned, designing it so the cable can't get caught and jammed it a VERY good idea.  If the cable does get wedged, it is amazing how tight a logging winch will wedge that cable, DAMHIKT.  ;D

Doug in SW IA

[John Mc]

I have two self-releasing snatch blocks. It's rare that I actually need to use both, but they both have come in handy at times.

I forget what company made this one, but I've never experienced a cable jam with it:

  


My second one was made by Forestry Forum member @apm .  He sold them on here at a bargain rate for a time. Eventually he got tired of being in the retail sales business and produced them for another company who resold them.

   

I had the same problem with the cable jamming that G_man did, and ended up ding the same modification. I was using a 10mm (+/-3/8") cable. I suspect a larger cable might not have had the problem. I've had no repeat of the problem since doing the modification.

   

Now that it has been modified, I prefer the APM snatch block. The pulley diameter is a little bigger, so less stress on the cable. Unfortunately, I've lost track of who is selling these snatch blocks these days, so can't include a link of where to buy. Perhaps if @apm is on here, he can comment on who (if anyone) is now selling them.

[apm]

Hi John,

Good to hear from you. We have not made any of the snatch blocks for several years. I doubt the people we were making them for have any left, by now. 

Thanks, 

APM (Greg)

[John Mc]

Thanks for the response, Greg. It certainly was a great product. If you ever get some slack time in your shop and feel like making more, I'm sure people here would snap them right up.