Log boom grapple build help.

[davedj1]

Hey all, I'm going to be building a log boom grapple for the tongue of my dump trailer and I'm having a hard time finding a close up view of the base bearing. Anyone have anything? I have a couple of different options at this time. One is a 4" od pipe inside a 4"id pipe with a bearing on top or a jeep wheel hub bearing cassette and build off of it. Any feedback is welcome.
thanks,
dave

 

[BHD]

Clutch throw out bearing, should work for a thrust bearing.

https://www.google.com/search?num=1...ed=0CAkQ_AUoAQ&biw=1280&bih=800&q=log grapple

 

[muddstopper]

I built a knuckel boom on my splitter for load large rounds to split. I used the jeep front axle hub where it bolts to the strut. My boom was 14ft long fully extended with just a set of log tongs for picking up the rounds. Worked really well until I decided to lift a 14ft, 16in dia log up for easy sawing. The jeep bearings are actually 2 bearing in the hub. They are spaced to close together for any real support once you factor in the extended length of the boom. The leverage of my long boom just popped the bearing out of the hub, almost took out my splitter engine. For a boom/grapple I think your pipe ideal will work much better than the jeephub.

I found an old electric crane off a mechanics truck and replaced my knuckle boom with it. This crane is simply a pipe in a pipe. Not sure of pipe size, but sure it isnt 4in as in your plan. I think it is rated for 1500lb. The pipe that slides into the outside pipe does have a smaller solid shaft sticking out the bottom, that goes into a bushed plate on the bottom of the outside pipe. This supplies additional support for the upright pipe and reduces the load on the sides of the pipes. Makes it much easier to turn since it reduces friction of the two pipes as they turn inside each other. The upright outside pipe is just welded to a flat piece of plate with 4 gussets welded on for support. It uses a small electric winch on top of the boom to pull the wood up. I used a 4 pole trailer connector to wire up a 20ft long remote cable which allows me to reach firewood I otherwise would have to either carry to the splitter or move the spitter closer to the wood.

I attached a pic of the boom, the base, and the stub I replaced at the bottom of the inside pipe. I also added a pick of the Knuckle boom and the jeep hub mount that I removed from the splitter.

 

[davedj1]

Thanks guys.
Muddstopper, that's exactly what I was going to use, I think your problem was you didn't leave the stub axle in place, it keeps the bearings from separating. I have decided to go a completely different route now though. I'm using a Jeep axle assembly with one tube cut off. I will be able to drive the yoke with a hyd. motor for turning and it should be much stronger. I'll post some pics once I get it under way. I've been shearing and punching steel this morning at a friends shop. He is going to cut a piece of 6" well casing for me. It sure was nice punching some 1" holes in some 3/8" plate! He also has an Ironworker which I used to cut the 3/8" x 6" to the lengths I needed.
dave

 

[muddstopper]

Post a few pics when you get it built. I had thought about going the same route with a ton rear end, but just havent gotten around to it.

 

[BHD]

I see your talking about building the boom not the grapple on the boom,

I have seen the use of wheel spindles,
My hoist is pipe on pipe on the smaller one, (harbor fright), and the larger hoist it has a thrust beating in the bottom of it, both of mine work well, and turn easy,

 

[davedj1]

BHD, I will be getting to build the grapple eventually. I'm searching for the motor for the rotator, I want to be able to hitch a post hole auger up to it. I think it will come in handy for building pole barns and fences.

 

[muddstopper]

We used to have some old tie cranes at work that used a orbit motor to turn the head using drive chains and sprockets The grapple was attached at the bottom of a shaft. The shaft was drilled for 2 lines to operate the grapple opening and closeing. The shaft ran thru a round collar that was machined to allow oil passage. this allowed for a continuous 360* rotation. Newer machines now use the more modern design 360 rotation swivels.

 

[BHD]

By rotator do you mean the boom rotation or to rotate the head of the grapple?

and by post hole digger do you mean you want the same motor to run the auger, as the head of the grapple?

 

[davedj1]

BHD, I mean the head of the grapple. I have seen a company that sells an atv trailer with boom grapple that they show taking the grapple jaws off and putting on an auger so yes, same motor if possible. It may not be possible, if not I may just use a hydraulic cylinder for 90* rotation of the grapple.
I'll post some pics later today of what I have done so far and what my "plan" is. You know plans can always change!
thanks,
dave