Building custom camper jack legs

[doug720]

Depending on the weight of the camper, but even the lightest campers weigh a 1500+ pounds - many weigh over 2500 pounds, there is a tremendous amount of force exerted into the jacks and mounts. Extend this weight off the ground by 5 feet or more - height where jacks mount to camper, and the jacks must be very strong.

Even lowered, unless the bottom of camper is supported on the ground, the jacks will be subject to huge leverage loads.

I had 3 Lance campers over the years, and removed them after every trip. IMHO, you want strong jacks, which typically means heavy.

 

[Alloy]

The 2 sections of aluminum will need something between them to prevent galling.

Two sections of steel will slide without galling

A ball screw will use less power and take more load than an Acme screw but the Acme screw is less expensive.

Try a search for lead screw or linear actuator.

Another route might be to modifying the jacks made for the front of a trailer. There are single jacks for bumper pull trailers and dual jacks for 5th wheels that are manual, electric and hyd.

 

[headingwest]

Mine is the same weight, then load it up and it's potentially double, then lift one forward leg too much and it could be taking 80 percent of the weight, then have 2 people in the cabover bed... so I'm working on 2000lbs per leg for a 1200lb camper.

 

[headingwest]

The 2 sections of aluminum will need something between them to prevent galling.

Two sections of steel will slide without galling

A ball screw will use less power and take more load than an Acme screw but the Acme screw is less expensive.

Try a search for lead screw or linear actuator.

Another route might be to modifying the jacks made for the front of a trailer. There are single jacks for bumper pull trailers and dual jacks for 5th wheels that are manual, electric and hyd.

Hi Alloy, I hadn't heard of galling, thanks for the heads up. Would a thin sheet of hpde or uhmw between the sections help? I''m guessing in a 10 year life that they'll be raised/lowered an average 20 times per year so 200 cycles.

This would also help resolve another issue of finding structural profiles with matching inner / outer sizes.
Thanks,

Jim.

 

[The Artisan]

Jim I using 1/16" umhw for my lifts to slide easily
Kevin

 

[Alloy]

Hi Alloy, I hadn't heard of galling, thanks for the heads up. Would a thin sheet of hpde or uhmw between the sections help? I''m guessing in a 10 year life that they'll be raised/lowered an average 20 times per year so 200 cycles.

This would also help resolve another issue of finding structural profiles with matching inner / outer sizes.
Thanks,

Jim.

Both UHMW and HPDE are good materials for this. If you'd like something better then use Delrin.

Stay away from Nylon as is expends in water.

 

[tanuki.himself]

spoke with another supplier today - he also recommended a 24mm trapzoidal/ACME thread with a 5mm pitch. He calculated I should be good upto 2000kg on a 900mm travel which is way more than I will need and that for me buckling on such a long travel is the limiting factor. He also reckoned that it would need a torque of 13Nm with my expected 400kg load - not sure what that will equate to for your expected load.

 

[headingwest]

Just looked at my cordless drill specs, it claims 60Nm torque so should raise 400kg no problem.


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[tanuki.himself]

Just looked at my cordless drill specs, it claims 60Nm torque so should raise 400kg no problem.


Sent from my SM-T825 using Tapatalk

i'm thinking exactly the same thing - although i may make up a lead and false battery connector for a 12v drill/driver so that I can run it off the camper battery rather than having to keep portable batteries charged. Also useful for drilling holes in hard ground for awning pegs and other ground anchors...

 

[TomsBeast]

I've been in your shoes, but wound up giving in, and just buying standard hydraulic camper jacks.

For their strength, their weight isn't that bad, even with a bad back.

If your cabover is lightweight, they used to sell these cable actuated lifting jacks with tripod bases.

 

[jwiereng]

maybe a threaded rod in tension would be better, less likely to buckle.

Could use a threaded rod of less diameter. You would need a longer rod and it would protrude when legs are retracted

 

[headingwest]

Possibly. The point of failure will be at the top of the leg where it attaches to the vehicle so the top of he leg needs to be strong. That or the leg buckling.

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[shade]

I'm surprised there isn't more interest in a trailer tongue jack. Relatively cheap, simple, strong. Adding an extended leg seems easy compared to fabricating a lifting device from scratch.

 

[redneckjeepr]

I'm surprised there isn't more interest in a trailer tongue jack. Relatively cheap, simple, strong. Adding an extended leg seems easy compared to fabricating a lifting device from scratch.

I made a set out of the longest travel tongue jacks I found and the only pain is having to wind each one up and down multiple times to actually lift the camper off the ground. For my truck, I need about 40 inches of lift to take the camper from ground level to truck bed level. This takes 3 full lifts from each jack to get the required lift which is a bunch of winding up and down. The other issue is that you have to support the trailer each time you need to unload the jack so that you can wind it back up and extended the drop leg. If I had known how big of a pain in the ass it would be, I would have probably ponied up for real camper jacks, but I already have nearly $300 in this set-up, so I feel like I should stick with it.