What leaf spring sliders are, and how you can build them in your Home Fabrication Shop.

Shackle setup

VS.

Leaf Spring Slider

What is better about leaf spring sliders?
Depending on setup, leaf spring sliders can provide great articulation and stability while also getting rid of big shackles that can hang down and drag on obstacles.

What kinds of leaf spring sliders are available?
Most leaf spring sliders are similar in design. All have a slot in which the bolt from the leaf spring can slide back and forth. some use small metal bearings and others use a hard type of plastic (UHMW, more on that later) to provide the sliding design.

There is no one right setup. It all depends on what you will be using the vehicle for. Now having had both the common shackle setup and the leaf spring sliders, I can readily say that both work well if set up correctly. The leaf spring sliders are a very tough design and I feel like they are more tight and predictable when used in the front suspension due to there being one less bushing and pivot point.

My favorite place to start researching is Google. You can and should start by searching “Leaf Spring Slider” but read on to learn how to make them yourself.

Everything starts with an idea, so after researching on Google quite a bit I came up with the highly accurate pencil drawing you see above (rulers are for chumps). One of these days I will learn CAD, but until then this is what we have to work with. You can see that I have the basic design laid out with some critical measurements. The thought is with the tube sleeve, I will be able to crank down on the leaf spring bolt without affecting the preload on the UHMW bushings or limiting suspension travel.

UHMW Plastic Sheet

Next step is to start gathering supplies! I picked up a sheet of UHMW at ~$60 for the whole sheet from a local plastic supplier, it was an odd ball already cut sheet so he gave me a pretty good deal. Don’t be afraid to ask for “drops” or already cut pieces when you only need a small piece. I have gotten many significant discounts by doing this. I also picked up the 1/2×1/2 square solid stock and tubing. The only tubing that they had in the size I needed was chromoly. I think they overcharged me for it, but it was such a small amount that I spent <$20 for 8 ft of 1/2×1/2 and 2ft of the chromo.

Total so far, is up to ~$80 and should have leftover materials.

Here is a snippet that I have written up on UHMW, why it is awesome, and why it should be used for this project.

I have had this idea in my mind and have been doing passive research on it for a long time. I just realized that it was all in my head, and I hadn’t posted any of it to share.

There is a lot of discussion on the topic, but relatively few people that have actually done the sliders and even fewer who have posted results.

UHMW is a plastic, but as far as plastics go, it is probably one of the most high tech plastics available. 

Quote:

Originally Posted by WIKIPEDIA – UHMW Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. …It has extremely long chains, with a molecular weight usually between 2 and 6 million. The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. [1]UHMWPE is odorless, tasteless, and nontoxic.[2] It is highly resistant to corrosive chemicals except oxidizing acids; has extremely low moisture absorption and a very low coefficient of friction; is self-lubricating; and is highly resistant to abrasion, in some forms being 15 times more resistant to abrasion than carbon steel. Its coefficient of friction is significantly lower than that of nylon and acetal, and is comparable to that of polytetrafluoroethylene (PTFE, Teflon), but UHMWPE has better abrasion resistance than PTFE.[3][4]

Most of it is way over my head, but the full Wiki article can be found HERE.


Essentially UHMW is made for bearing/sliding applications. They use if for everything from launching boats to fake knees and hips. 

UHMW pros:
Self lubricating – greasing it would actually reduce the life because it would attract dust/grit which would wear it faster.
High impact resistance
Can be machined
Is not brittle, does not crack like plexiglass (excluding lexan)
It has a temperature range from -240*F to +266*F

UHMW Cons:
It is still a wearable item. Hopefully it doesn’t wear out fast, but if it does, there is no risk of catastrophic failure due to the slot design.



Below are some links to threads that I have found useful about the shackle slider boxes:

http://www.pirate4x4.com/forum/gener…-shackles.html

http://www.pirate4x4.com/forum/gener…kle-boxes.html

Leaf Sliders



Clearly the easiest way for me to do this would be to go buy the ones from Tim at Liquid Iron Industries.

But, if I buy the part, I get one part. If I buy the tools to make the part, I can make as many as I want, and I get a free lesson in the study of plastics.

Grab a beer (in this case a home-brew espresso stout) to make sure your brain doesn’t overheat!

Start cutting materials down to length (specified in the engineerd drawring above)

Start laying out the parts to get a feel for what it will look like. The brass looking tubes are out of a leaf spring bushing kit and are exactly 3″ wide which works perfect as a spacer for building these.

Next is to build a paper template of the sides of the sliders and center punch the two holes at either end onto the steel.

In my home fab shop, when I want to replicate parts, I weld them together then drill them all at once so they match (almost) perfectly!

Mmmmm fun times with the drill press. In this picture I am drilling the ends of the slot.

After I drilled the ends of the slot in the drill press, it was time to make the rest of the slot. My plasma was broken at the time I was doing this project so I improvised and cut the slots with my angle grinder and a vice.

Next, tack on the .5″ square stock that will eventually become the support for the HDPE pucks.

Set up the proper spacing and tighten down the bolts.

Use the MIG welder and tack on the top plate.

MIG Tack on the back plate

Once they are all set up. It is important to double check all measurements BEFORE final welding. I only say this because I have made mistakes before that would have been easier to remedy prior to fully welding.

Cut out the UHMW pucks on my Father in law’s table saw.

Next up, drill holes for the sleeves to fit inside of the UHMW pucks. This is an important part because the metal sleeves inside of the UHMW pucks will determine the spacing and preload on the UHMW bearings.

I got bored and decided to whip out the ol’ TIG welder. I really need to practice TIG welding more often to build up some better skills. For now this will work though.

More TIG. I gave up and had to MIG weld the inside joints because it was too hard to do with the TIG.

Had to cut out and fabricate some front spring hangers also. I set them up with 3 holes so they are adjustable if I need it in the future.

Finished products. Adjustable front spring hangers with leaf spring sliders at the rear.

Installed in Ol’ Blue

The leaf spring sliders seem to work really well. They ride nicely on the road and flex more than enough offroad.

If I were to do this again. Unfortunately I would probably just buy prefabricated leaf spring sliders. You can find them in a quick search for anywhere between $30-$100 dollars. I built my leaf spring sliders with long slots for lots of travel, but as it turns out the springs really don’t need that much room to travel. I built mine 9″ long with a 7″ slot but I easily could have made them with only a 5″ slot.

Link to the installation of the leaf spring sliders on Ol’ Blue with more pictures.

I hope this article helps. I know that when I was initially researching this subject there really wasn’t a lot of information. It took me a lot of time to get enough information together to build these. Please leave your questions/comments.