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3pt. plate compactor

larboc

Limestone cowboy
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May 19, 2020
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Fed up with how much time it's taking to use the walk behind on the fill portion of my shop build (https://irate4x4.com/shop-and-tools/...uilding-a-shop), I'm going to try to red green a larger, more powerful unit for the tractor. It's also snowing and my tractor has a heated cab.

My plan is to not plan too much.
I looked around the yard and mobile home axle hubs have the best bearings for the job out of what I have on hand so I'm going to build the exciter out of a pair of them shortened and mounted to a machine frame I had laying around.

I cleaned up the extra stuff from the frame and cut the hubs off one axle tonight.

I've got some ideas on how to make them spin. Synchronizing them is the challenge.

My goal is a 60"x24" plate with 20,000 lbs of compaction force and the MH bearings last at least 5 hours

IMG_20201001_205916464.jpg
 
How much fill are you doing and what type of material is it?

Would a sheep's foot type be better for the bulk of in, then finish it off with the walk behind plate?
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Synchronizing them is the challenge.
chain drive to a common jackshaft solves any alignment and timing issues
though running both in single shear will be a lot weaker than both with one shaft, though alignment will be tougher with the two sets of bearings...

ETA: from my research on the subject years back I'm pretty sure you want something around 3000 RPM on the vibrator
 
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oh right, make sure and blobberate on one hell of a piece of plate to keep the counterweight out of your brain when it breaks free
 
I would have gotten an 8-lug (or whatever bolt pattern you have around) UB and CV shaft from the junkyard and then welded a flange for a PTO shaft to the cup that holds the bearing together and direct driven it off the PTO. Pour an old tire and rim half full of concrete would vibrate nicely and being on the same axis at the PTO when it fucks off it goes sideways instead of at you.
 
That's going to shake the crap out of you and your tractor. There is a reason that contractors who own their equipment put rock hammers and other vibrating equipment on their old stuff and not the new ones.
 
[486 said:
;n150930]oh right, make sure and blobberate on one hell of a piece of plate to keep the counterweight out of your brain when it breaks free

This for sure. When I was maybe 14-15 I built a small soil screener in my parents one car attached garage. That pile of junk came apart, jumped off the ground and punched a hole in the ceiling while flailing metal parts everywhere. That was the last day of the nifty sifty top soil screening business. :laughing:
 
How much fill are you doing and what type of material is it?

Would a sheep's foot type be better for the bulk of in, then finish it off with the walk behind plate?
​​​​​​

Well graded clean sand, static sheepsfoot isn't a good way to pack it. Needs lots of pressure and/or vibration.
 
[486 said:
;n150924]
chain drive to a common jackshaft solves any alignment and timing issues
though running both in single shear will be a lot weaker than both with one shaft, though alignment will be tougher with the two sets of bearings...

ETA: from my research on the subject years back I'm pretty sure you want something around 3000 RPM on the vibrator

My goal is 60hz/3600rpm. My initial plan was to just buy some 1.5" keyed shaft from surplus center and several pillow blocks but when I started looking at bearing ratings, grease lubricated sealed ball bearings are nowhere near capable of that speed and load. The other problem is that normal roller chain isn't rated for the kind of surface speed a sprocket that would fit over a 3" shaft would see (4" or so OD sprocket) unless it's running in oil. I'd like to do two sprockets and an idler so that the shafts counter rotate but I'm scratching my head a little at how to do it without investing a ton of time. At this point I'm going to take a chance that driving them both with a v-belt and identical pulleys is going to get them close to the same speed, and then the vibration of the entire unit will keep them synchronized. If this doesn't work it would probably be pretty obvious.

I've got a plan to get both spindles welded on straight and in good alignment using either a lathe or some all thread depending on my level of motivation.
 
I would have gotten an 8-lug (or whatever bolt pattern you have around) UB and CV shaft from the junkyard and then welded a flange for a PTO shaft to the cup that holds the bearing together and direct driven it off the PTO. Pour an old tire and rim half full of concrete would vibrate nicely and being on the same axis at the PTO when it fucks off it goes sideways instead of at you.

Need 3600rpm, not 540 rpm.

I don't know what a unit bearing is rated for, but when I was looking at the bearings in a 14-bolt hub they aren't capable of getting close to 3600rpm. I also don't know how well the bearings in a UB would stand up to a counter balanced 20k lb radial load.
The bearings in the MH axles are 3600/3000 so I'll be pushing it a little already with those but I plan to run the hubs with oil instead of grease so that should help.
 
This for sure. When I was maybe 14-15 I built a small soil screener in my parents one car attached garage. That pile of junk came apart, jumped off the ground and punched a hole in the ceiling while flailing metal parts everywhere. That was the last day of the nifty sifty top soil screening business. :laughing:


Sounds awesome! I made a little sand sifter a long time ago... It was small enough that if it came apart it wouldn't do much damage. It did work quite well to clean larger trash and rocks out of river bottom sand to use for sandblasting. The sand itself was a bit fine to cut really well, but it got a few projects done anyhow.
 
I'm curious to watch this.

Edit: I'm requesting a solemn irate oath to take video of whatever turns out of this effort in action.
 
My goal is 60hz/3600rpm. My initial plan was to just buy some 1.5" keyed shaft from surplus center and several pillow blocks but when I started looking at bearing ratings, grease lubricated sealed ball bearings are nowhere near capable of that speed and load. The other problem is that normal roller chain isn't rated for the kind of surface speed a sprocket that would fit over a 3" shaft would see (4" or so OD sprocket) unless it's running in oil.

sounds way too expensive, buying parts...
I'd go with either used up motorcycle chain, or old timing chains, mainly because I've got a bunch of that junk saved from the trash
larger diameter sprockets will reduce the heating of the chain, you do not want small diameter sprockets with high speed chains, surface speed is nothing when compared to the angle each link has to bend to wrap around the sprocket
I'd just run them open, spray some used oil on them every once in a while and expect them to be sacrificial with all the dust floating around
 
Need 3600rpm, not 540 rpm.

I don't know what a unit bearing is rated for, but when I was looking at the bearings in a 14-bolt hub they aren't capable of getting close to 3600rpm. I also don't know how well the bearings in a UB would stand up to a counter balanced 20k lb radial load.
The bearings in the MH axles are 3600/3000 so I'll be pushing it a little already with those but I plan to run the hubs with oil instead of grease so that should help.

In my experience parts from a truck axle rated at 4-6k are gonna be a hell of a lot more beef than trailer parts rated for 7.5k. You'll probably be fine either way but a single unit bearing would be super easy to design for.

The bearing will have no problem being over-sped until you start talking about super high speeds. The lubrication and reduced life will probably be your first issues. Finding a drive-train to turn your 540rpm into 3600rpm is going to be your biggest issue. You need 7:1. Maybe add an extra bearing to the front of an old truck 4spd to support the input and then run it backwards in 1st/reverse

Do you really need 3600? If 540 will work but just be slower that would likely be a good tradeoff.
 
[486 said:
;n151273]

sounds way too expensive, buying parts...
I'd go with either used up motorcycle chain, or old timing chains, mainly because I've got a bunch of that junk saved from the trash
larger diameter sprockets will reduce the heating of the chain, you do not want small diameter sprockets with high speed chains, surface speed is nothing when compared to the angle each link has to bend to wrap around the sprocket
I'd just run them open, spray some used oil on them every once in a while and expect them to be sacrificial with all the dust floating around

That's kind of my plan if they don't auto-sync with a belt. 26 tooth #35 sprocket tack welded on the tube OD and plenty of #35 chain on hand. I keep the sand so wet during compacting there isn't much dust.

I'm looking at charts like this, which say that no go-cart or mini-bike chain running at 10hp at 4000rpm in free air around a 14 tooth sprocket should ever exist.
https://www.renoldjeffrey.com/media/2395574/ansi-standard-roller-chain-renold-jeffrey.pdf

Based on what the chart says vs. how many miles I've got on mini-bikes and go-cart chains, I think what you said, or maybe even a drip oiler or something similar would be good enough for this. Maybe even o-ring chain would be worth it.
 
In my experience parts from a truck axle rated at 4-6k are gonna be a hell of a lot more beef than trailer parts rated for 7.5k. You'll probably be fine either way but a single unit bearing would be super easy to design for.

The bearing will have no problem being over-sped until you start talking about super high speeds. The lubrication and reduced life will probably be your first issues. Finding a drive-train to turn your 540rpm into 3600rpm is going to be your biggest issue. You need 7:1. Maybe add an extra bearing to the front of an old truck 4spd to support the input and then run it backwards in 1st/reverse

Do you really need 3600? If 540 will work but just be slower that would likely be a good tradeoff.

540 won't work for well graded clean sand. Lots of compaction data out there that granular soil like this needs high frequency to compact. 40Hz is about the minimum seen on big stuff. Walk behind single plate compactors are closer to 100Hz.

Keep in mind that a unit-bearing spinning at 3600 rpm would be the equivalent of a truck sized tire going 350 mph. MH tires speed is still stupid, like 260 miles an hour but because I can have the bearings in oil instead of grease it helps to get rid of the heat and looking at the bearing spec. sheets, they should be okay for 50 million revs. at the loads and speeds I'm talking about. I can't find sheets for unit-bearings, but I suspect that because they are so much bigger diameter to let axles shafts pass through, they aren't going to last as long as a MH axle at 3600, even though they can probably handle more weight at lower speeds. Likely more inline with bearing specs for 14-bolt hubs.
 
Your belt will not work, I give your chain a 10% chance of working. You underestimate the forces your dealing with. I have 20 shaker mechanisms between screen boxes and vibrator feeders. Best bet if to find a old vibrator feeder and cut it down and use that for a compactor. They are built like brick shithouses. The little two shaft compactors have 1” wide gears and cylindrical roller bearings.

Go on Craigslist and find a old 800-1200$ pull behind vibratory roller and be done.

i have a vibrator plow that’s Hooked to a skidsteer plate. I’m sure you could put a plate on and make that work for you. You could pick that up and try it.

I could prolly let you use a self propelled compactor as long as I get it back. It looks like I have three here atm. I could make one go missing for a while before dad goes looking for it.

960A1F18-F19D-4DC4-A6D3-3716AF47E662.jpeg
006814D2-85D2-458C-BF65-EE3E42D41A70.jpeg
 
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Keep in mind that the hubs are designed for load more less inline with the bearings (radially) and from one direction. A load offset from the bearings will change the forces on the bearings a decent bit, and rotation of an offset load is going to be flexing the spindles and what they mount to. Rotational reversed bending (which is what you're doing) is the worst thing you can do for fatigue. Also note that MH bearings are designed undersized and not speced for long life. You can do the calcs, but I think bearing life is less of an issue the fatigue failure of the spindles and weldment they attach to.
 
So, I did some more digging outside of mcmastercarr and it looks like 14-bolt hub and carrier bearings are okay above 3600rpm not sure where mcmaster got their 2000rpm number from. 387AS is good to 6280lbs C90, the outer hub bearing 5610lbs. This has me thinking about pulling the 14-bolt with the grenaded g80 and stuck brakes out of the '85 K30 and turning it into an exciter. I'd probably pull the pinion or ring gear so the pinion isn't going 14,760RPM and mount a pulley on a hub and weld the spiders. Spin the pulley with either a small engine or a golf car axle backwords from the PTO. Put an offset weight on each hub, and bolt weights in the holes where the ring gear should be, or remove material from the carrier dependign on what the calculations show needs to happen.

This should be able to deliver 36klbs of rotating force for at least 400 hrs of bearing life and is pretty close to the advertised force/C90 bearing rating of every compactor exciter I could find bearing part numbers for. 36klbs is intermediate sized bomag territory if I can find big enough metal to keep this all together.

A 750lb reversable packer is $190/day from the local rental place, that's probably the right thing to do but it still wont be as powerful as this should be.
We'll see where I get to by the end of the weekend, maybe I'll have to make an emergency trip to wausau panz, but I'll have to find something to bring you that you need or reasonable cash.
 
So, I did some more digging outside of mcmastercarr and it looks like 14-bolt hub and carrier bearings are okay above 3600rpm not sure where mcmaster got their 2000rpm number from. 387AS is good to 6280lbs C90, the outer hub bearing 5610lbs. This has me thinking about pulling the 14-bolt with the grenaded g80 and stuck brakes out of the '85 K30 and turning it into an exciter. I'd probably pull the pinion or ring gear so the pinion isn't going 14,760RPM and mount a pulley on a hub and weld the spiders. Spin the pulley with either a small engine or a golf car axle backwords from the PTO. Put an offset weight on each hub, and bolt weights in the holes where the ring gear should be, or remove material from the carrier dependign on what the calculations show needs to happen.

This should be able to deliver 36klbs of rotating force for at least 400 hrs of bearing life and is pretty close to the advertised force/C90 bearing rating of every compactor exciter I could find bearing part numbers for. 36klbs is intermediate sized bomag territory if I can find big enough metal to keep this all together.

A 750lb reversable packer is $190/day from the local rental place, that's probably the right thing to do but it still wont be as powerful as this should be.
We'll see where I get to by the end of the weekend, maybe I'll have to make an emergency trip to wausau panz, but I'll have to find something to bring you that you need or reasonable cash.

Don’t forget your gonna need some extremely beefy isolators to isolate your tractor from the plate. If Not your gonna lose a ton of vibration into the tractor vs into the ground where you need it.
 
I'm looking at charts like this, which say that no go-cart or mini-bike chain running at 10hp at 4000rpm in free air around a 14 tooth sprocket should ever exist.

so run it around a 40 tooth sprocket
 
Don’t forget your gonna need some extremely beefy isolators to isolate your tractor from the plate. If Not your gonna lose a ton of vibration into the tractor vs into the ground where you need it.

bonus points for electric motor drive, towed with a rope
 
[486 said:
;n151829]

bonus points for electric motor drive, towed with a rope

20+hp electric motor and drag it around with the power cord. :laughing:
 
Is water an option? Years ago we built in a place where drainage was great and would bring in some fire trucks and lay down thousands of gallons of water to compact before a pour, the water was gone in a matter of an hour or so, worked great.
 
I've done it, but it was with a cat 815 :flipoff2:​​​​​​

Those diesel vib plates panz posted work well in sand though.

Those are our gas powered fleet. My dad bought a diesel one and now the gas ones sit.
 
Is water an option? Years ago we built in a place where drainage was great and would bring in some fire trucks and lay down thousands of gallons of water to compact before a pour, the water was gone in a matter of an hour or so, worked great.

Compacting without water would be like fucking with a soft dick. :flipoff2:
 
Those are our gas powered fleet. My dad bought a diesel one and now the gas ones sit.

Gotcha, I just assumed diesel by the size. We had a job where we had to get 95% in sand :rolleyes: we made it in the flat with a plate, but ended up using a Ram x to get it on the slopes.
 
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