Building a 3pt Log boom+winch

[Marshy]

Yeah, if nothing else I will have a good log boom to lift logs and pull them out. Still liking the scissor design.

 

[Marshy]

Apparently Massey Ferguson had something similar a looooooong time ago.

 

[XP_Slinger]

Apparently Massey Ferguson had something similar a looooooong time ago.
View attachment 111515

Would a boom that long reduce your lifting ability? Or am I misunderstanding the top link leverage of the 3 point.

 

[Marshy]

Would a boom that long reduce your lifting ability? Or am I misunderstanding the top link leverage of the 3 point.

No, your adding mechanical advantage if the boom is longer between the 3pt pin and the pivot, vs the length between the pivot to the end of the boom.

I have to do some measuring but I was thinking about 2-2.5' between 3pt and pivot, and about 18-20" from the pivot to the hook.
That would yield 1.3:1 or 1.5:1 leverage.

 

[Marshy]

I need to double check that though.

 

[Ryan Browne]

Would a boom that long reduce your lifting ability? Or am I misunderstanding the top link leverage of the 3 point.

I think yes, it's gonna reduce the amount you can pick up. You'll still be able to generate the same amount of lift force with the three point, but since it's further away from the lift arms and top link, any weight you lift has a magnified effect on the tractor. Also, the higher the weight is lifted means need stability for the tractor. A tractor like yours should be able to lift quite a bit even a few feet back, but at some point you'll either hit the relief (hopefully), break something (hopefully not), or need a bucket full of gravel or firewood to keep the front end down.

No, your adding mechanical advantage if the boom is longer between the 3pt pin and the pivot, vs the length between the pivot to the end of the boom.

I have to do some measuring but I was thinking about 2-2.5' between 3pt and pivot, and about 18-20" from the pivot to the hook.
That would yield 1.3:1 or 1.5:1 leverage.

Wait, explain that again would you? I see what you're saying, but I just don't think you can get extra lift capacity for free.

 

[Ryan Browne]

This is intriguing. It's from Tractorbynet.

 

[Marshy]

This is intriguing. It's from Tractorbynet. View attachment 112075

That's not the design I'm using though.
Look back at the top of this page.

 

[Marshy]

Like I said, I have to look into it more but by having the boom scissor I thought I was adding mechanical advantage. That may not be the case because it total distance from the length of the arms to the load like you were saying.

What I was call it the pivot I was referring to the location of the top boom where it pivots.

 

[Ryan Browne]

If you're talking about this design, I just still don't see it multiplying lift force.

I'm not trying to call you out or anything, so I hope I'm not coming off as rude. Just trying to have an enjoyable discussion.

I think what the design shown above achieves is the removal of the top link. If you used a regular top link with a setup like that (basically to replace the square tubing to the left of the current pivot) it'd be more difficult to make the rest of the boom rigid. This design allows a simple way to make the whole thing strong without needing to gusset a right angle. It needs to pivot there though rather than being rigid because of the way the three point works. Because the arms and the top point are mounted in different planes, there would be a major binding problem if it didn't pivot there.

 

[Marshy]

View attachment 112077

If you're talking about this design, I just still don't see it multiplying lift force.

I'm not trying to call you out or anything, so I hope I'm not coming off as rude. Just trying to have an enjoyable discussion.

I think what the design shown above achieves is the removal of the top link. If you used a regular top link with a setup like that (basically to replace the square tubing to the left of the current pivot) it'd be more difficult to make the rest of the boom rigid. This design allows a simple way to make the whole thing strong without needing to gusset a right angle. It needs to pivot there though rather than being rigid because of the way the three point works. Because the arms and the top point are mounted in different planes, there would be a major binding problem if it didn't pivot there.

Please go back and read more. That is the design I am going to copy.

 

[Ryan Browne]

Please go back and read more. That is the design I am going to copy.

I read the whole thing and I think I understand what you're trying to do. Am I missing something? I think the design that you're gonna copy is a good one.

 

[huskihl]

Using either design, you lose in lifting capacity, but gain in lifting height. I'm not sure of the formula, but I would imagine what you gain in a percentage of height would be similar to the percentage you'd lose in lifting capacity. The only way to gain a mechanical advantage would be to lift between the tractor and the end of the three-point arms. But with a respectable size tractor, giving that you're only lifting one end of the log, I really don't see where you'd have any issues

That being said, I really like the design of those last pics posted. Seems very rugged.

 

[mels]

We've got one of them tractor supply 3pt boom poles, and a hydraulic top link.

I'm no physics guy, or geometry or whatever the heck but I'd like to think that hydraulic top link gives me a lifting advantage because where the 3pt is a simple dead-lift straight up pretty much, that top link gives me a mechanical advantage when I retract it.

Sounded good enough to me at the time when I bought it, so at the risk of sounding foolish (like I need any help with that, lol) I just keep telling myself that...

The concern as was mentioned above, is that the front end of the tractor (old '58 Ford 641) gets light in a hurry. Concern enough for me anyway that I nabbed that old stone boat.

That Ranger unit with the tongs looks beefy as all get-out though.

 

[XP_Slinger]

I’m going to start out with a tong set up as I don’t have the coin to drop on a skidding winch right now. Probably just going to get a 3 point draw bar receiver and add about a 24” boom to hang the tongs off of.

 

[junkman]

I tried something like this with a small harbor freight type engine lift ,it worked sort of with tongs ,but i ended up building forks for my skid loader ,the fork lift works much faster for me .,with heavier logs it seemed to roll over on my 3 point ,i have a small tractor though ,21 hp kubota ,it is handy if i need to lift something heavy like a car transmision out of my pickup bed and back it into the shop though .I do not have any images installed ,but i can get about 6 feet of lift between the bottle jack and the 3 point

 

[Jimmy in NC]

I want to add to something touched on briefly by others, but anytime you put the pullabove the rear axle, you exponentially increase the ability to loose stability. Lots of people been injured or killed using a boom pole to pull a not so large log.

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[XP_Slinger]

I want to add to something touched on briefly by others, but anytime you put the pullabove the rear axle, you exponentially increase the ability to loose stability. Lots of people been injured or killed using a boom pole to pull a not so large log.

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Excellent point. My goal is to have the log no more than 16” off the ground regardless of lifting capacity.

 

[Marshy]

I want to add to something touched on briefly by others, but anytime you put the pullabove the rear axle, you exponentially increase the ability to loose stability. Lots of people been injured or killed using a boom pole to pull a not so large log.

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That's a good point. I have more than a couple hours on log tractors so I'm versed in do's and dont's. I'm going to have some chain hooks on the frame thst supports the boom so the log will be lifted by the 3pt frame when dragging.

 

[XP_Slinger]

That's a good point. I have more than a couple hours on log tractors so I'm versed in do's and dont's. I'm going to have some chain hooks on the frame thst supports the boom so the log will be lifted by the 3pt frame when dragging.

You start building yet Marshy?