Cant see the forst for the trees???

bedway · May 20, 2007, 01:07:45 PM

I took the leaf springs that are off a jeep. They have five leafs in them. I positioned them under my log bed in the position i wanted. I made some shackles for the front and tacked them to the frame.

Not knowing where the rear shackle should be placed and its dimensions i figured id put some jacks under the frame and jack the springs up till the frame lifted off the stands. That way i would have some idea where to place them and how much the spring compressed before it picked the frame up,=travel. To my surprise the springs were nearly straight and hadnt picked the frame up.

This pic doesnt show the springs compressed, but trust me they were. I assume it has something to do with the rear of the spring haveing to be restrained in shackles also, even though the rear ones pivot.

I thin k ive stumbled across one of those things that are not as simple as they appear at first. Any of you have knowledge in this area feel free to enlighten me,,HELP,,bedway ;D

DanG · May 20, 2007, 02:45:49 PM

The first thing that comes to mind is, your springs may not be stout enough. That mill is probably a good bit heavier than the hind end of a Jeep.

Another possibility is that not having one end of the spring secured to the frame may be allowing the spring to lengthen too much. Normally, the spring would be restricted in how much length it can gain as it straightens. I would just place that second shackle at the "normal" length of the spring, then couple it to that shackle via a pair of links, so it can move but can't move too far.

I haven't had great luck using automobile springs on trailers. They usually are not stiff enough. The hardest I ever seen Fla._Deadheader laugh was when we loaded the Hootiemobile onto the old trailer I had. It turned the springs completely inside-out, and the frame sat right down on the axles! Then, when I unloaded it, the trailer jumped clean off the ground.

:D :D :D I always had to restrict the load on that trailer because the truck springs that were under it just weren't up to snuff.

Furby · May 20, 2007, 03:17:45 PM

Jeep springs are pretty soft springs.

bedway · May 20, 2007, 04:19:05 PM

When i tried to lift it with the springs i was allowing the front end of the frame to stay on the jack stands. Im thinking, ( and i think pretty accuately) that the complete package weighs in around 1500 pounds. I tried it again rolling the saw head forward of the springs, and it still didnt lift it and the leafs were nearly straight. I felt at first the obvious thing is the springs are to weak. The ones in question are off the front end of a cj-5 that had a six cylinder in it. :(

DanG · May 20, 2007, 04:27:50 PM

If they're front-end springs, they should be strong enough. Try clamping a block to the frame to keep the spring from lengthening too much as you compress it. I still think the shackle should be at the normal length of the uncompressed spring.

theorm · May 20, 2007, 04:51:52 PM

Quote from: DanG on May 20, 2007, 02:45:49 PM

It turned the springs completely inside-out, and the frame sat right down on the axles! Then, when I unloaded it, the trailer jumped clean off the ground. :D :D :D

DanG, Do you have a video of that? That would be a hoot! 8)

Theo

logwalker · May 20, 2007, 05:22:14 PM

I have to disagree with DanG. The springs have to be allowed to flex unrestrained or you are just creating an arch and would get no flex beyond that point. The shackles have to be designed so the springs can completely flatten.

rebocardo · May 20, 2007, 06:24:31 PM

> The ones in question are off the front end of a cj-5 that had a six cylinder in it.

imo, Never use front springs for a trailer.

Because for the most part they are the most flexible springs on a vehicle and many times have a variable rate built into them so the vehicle does not drive like a truck, literally. They are meant for a soft cushy ride.

On yours the shackle/pivot was probably in the front and the hanger (U shape) in the rear. Which means to work properly, the ends of the spring can not be on equal heights on both ends if reusing the Jeep parts (can't tell by the pictures).

If you are going to use car/truck springs on the cheap, then get a set from a truck or van such as a F-350/E-250 where the leafs look like they were made from 3/8 material and are good for 5,000 pounds.

The springs you have are probably rated for 2000 pounds for the set, if that. A $50 set of springs with four leafs and hangers from northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company would be good for 3500 pounds, such as item# 12523.

DanG · May 20, 2007, 09:00:16 PM

Quote from: logwalker on May 20, 2007, 05:22:14 PM
I have to disagree with DanG.

I have to disagree with your disagreement with me, Logwalker. If the springs are allowed to flatten all the way out, they will turn inside-out like mine did. Those springs didn't have much of an arch to them to start with, so the links were long enough to allow them to flatten all the way out. I'm having a little terminology problem here, so bear with me. I'm referring to the U shaped piece that is welded to the frame as the shackle. The little 3" pieces of bar stock that attach one end of the shackle to the spring, I'm calling a link. The links allow the spring to flex and provide some cushioning to the load, but keep it from flexing too much. Without it, you may as well just weld the axle to the frame and save all the bother, which is a valid method, as well. Like most other stuff, springs are made for a specific purpose, and perform less well when used for other purposes. The multiple leaves are intended as a damper to limit bounce, rather than to bear weight, in most automotive springs. The main spring in those stacks, the one with the curly-Qs on the end is really bearing all of the weight.

Bedway, go to a large mobile home dealer and look in their junk pile. They probably have some busted axles there and will sell you the springs from them real cheap.

tomboysawyer · May 20, 2007, 09:15:05 PM

Quote from: rebocardo on May 20, 2007, 06:24:31 PM
On yours the shackle/pivot was probably in the front and the hanger (U shape) in the rear. Which means to work properly, the ends of the spring can not be on equal heights on both ends if reusing the Jeep parts (can't tell by the pictures).

If you are going to use car/truck springs on the cheap, then get a set from a truck or van such as a F-350/E-250 where the leafs look like they were made from 3/8 material and are good for 5,000 pounds.

The springs you have are probably rated for 2000 pounds for the set, if that. A $50 set of springs with four leafs and hangers from northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company would be good for 3500 pounds, such as item# 12523.

We bought those springs from northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company for our sawmill. You're right - the Jeep springs are not designed to go on a straight frame.

The northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company springs come with instructions on how far apart the shackles are supposed to be. I don't know that it was obvious at first, but we got the information from the manufacturer. I think we figured our mill was close to two ton. Our 2" axle ended up bending after driving for 1.5 miles with the sawhead on the mill.

Some times cheap is more expensive.

Fla._Deadheader · May 20, 2007, 10:10:26 PM

When we built the tri-axle log trailer, we got used trailer axles. Some of those single leaf springs were bent. We bought all new ones.

bedway · May 21, 2007, 09:55:41 AM

This might be an exersize in futility, but im building the rear shackles complete with the pivot assembly. Im not going to weld them, but clamp them to the frame in an arbortrary location. Then ill jack up on the springs again to see if this makes a difference. As i stated before the total weight of this mill cant be more than 1400 pounds. I guess the easiest thing to assume is the springs are to light,, but on occation my wife has been known to call me bullheaded,,,,,i wonder why :D,,bedway

firecord · May 21, 2007, 01:07:16 PM

Copy the set up that was on the Jeep from hanger eye to hanger eye. You will be fine. The springs will bear the weight + some. I have seen Stock CJ's running big block V8's, wenches, heavy bumpers with no efect on the springs at all. And yes DanG is right if the whole setup is not installed it will flatten out too much.

fuzzybear · May 21, 2007, 01:27:51 PM

You have to have the axle assembly completly installed or they will not work. As far as placement on the frame, the rule in trailer building in 60/40. This means that if your frame from hitch to end is 20' the center of the axle should be mounted 12' from the front. This will allow the trailer to be ballanced properly.
NOTE.... the head of the mill will have to be positioned over the axle during transport. I noticed in the photo you do not have the front shackles installed. These should be swivel shackles not solid mount.

bedway · May 21, 2007, 05:01:54 PM

Ok, i got the rear shackles built with the swivels. I positioned them approx. 1.5 inchs beyound normal spring positon with no weight on the spring. I then put jacks under the axle and jacked the springs up until it lifted the frame with saw head centered above the axle off the jack stands. Only the tongue was setting on jack stands at this point, with im guessing maybe 75 pounds at the front. You can see in the pictures that the spring is still not straight. Im happy with this set up and think im going to weld brackets permanent. If for some reason its needed i guess i could build some helper leaf in or rig in some small coils to help with the weight,,Ok what do ya all think,,,bedway

Don P · May 21, 2007, 05:11:21 PM

I don't know nuthin but I'm watching this hoping to find out. One thing I've always heard is that impact loading is 2-3 times just gravity load. You might want to think about throwing a plank across the rails and some more weight while watching the spring deflect ???

firecord · May 21, 2007, 05:29:29 PM

Bedway
I would not go past normal, you don't want the spring hangers (not swivels) straight up and down. They should slightly point to the rear for flex. The springs in your photo look sprung! As in flattened out! Are these some you had or purchased? You can take them to a spring shop and have them re-arched, however they won't stay re-arched. Springs are basically memory steel and once they go flat they will return to flat. If it were me I would go buy some new springs. Northern hydraulic has a fairly good price or look into having some made locally. Springs are the cheapest part of a good axel set up. my 0.02

firecord · May 21, 2007, 05:36:05 PM

It's northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company now?

Anyway
Trailer Springs — 4500-Lb. Capacity
Two spring sets double your capacity. Example: two 2000-lb. spring sets have 4000-lb. total capacity. Each spring set includes two 1 3/4in.W springs w/ 9/16in. eyes and 25 1/4in. center. U.S.A.

$44.95 + shipping not a bad deal

Jeff · May 21, 2007, 05:43:54 PM

Quote from: firecord on May 21, 2007, 05:36:05 PM
$44.95 + shipping not a bad deal

Its a lousy deal in the scheme of things...

I boycott and will continue to boycott northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company since they went to china and copied one of our favorite sponsor's patented tools and is now selling a very inferior copycat product under the northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company name. I would hope that all forum members consider doing the same. northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company has proven to me a severe if not total lack of ethics. >:(

Contact sponsor Eggimann to the left. they can get ya anything you need.

bedway · May 21, 2007, 06:05:54 PM

Firecord,,,,the pictures you see are of the axles loaded with the weight of the mill setting on them. In their relaxed position (no load) they have about 7 inches of arch. These springs came out of my son in laws jeep. There was nothing wrong with them other than he put a lift kit in his jeep and it included new springs etc.

Quote from: firecord on May 21, 2007, 05:29:29 PM
Bedway
I would not go past normal, you don't want the spring hangers (not swivels) straight up and down. They should slightly point to the rear for flex.

Im a little confused by this firecord,,of course my wife says i was born confused.,,,,,bedway

rebocardo · May 21, 2007, 06:13:49 PM

If you are not happy with ride height and such, throwing on a set of rear air bags for a Ford pickup (since they have the flat top mounting) is always an option. A $150 option!

Just inflate them to the height you want and use the springs as a safety measure in case one deflates.

beenthere · May 21, 2007, 06:33:16 PM

I guess I can see not having the hangers straight down.
Consider hitting a bump, where they (hangers) angle slightly forward with no load, then stay forward when the load comes down on the springs. Might cause some heartache if they do that.

Furby · May 21, 2007, 08:43:37 PM

Bedway, the top part should be shifted forward so that the spring can move without binding.

Yup, stay away from northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company!
Springs can be found REALLY cheap by doing a Google search for trailer parts.
Farm supply stores such as TSC and the like carry them as well. ;)

Gary_C · May 21, 2007, 09:21:38 PM

Those springs are what is called double eye springs as compared to single eye springs where the other end is a slipper end that just rests on a flat support. The mounting idea is the same however as one end, always the front end is fixed and the other end is allowed to move front and back without restriction. So your rear mounts must never restrict the elongation of the spring under load nor allow the eye to rotate forward and go over center when all the weight is taken off the axle.

In other words that back hanger should never restrict the springs from getting longer or something will break or bend.

DanG · May 22, 2007, 01:24:41 AM

Let's just look at the dynamics of the whole thing for a sec. The "normal" length of the springs is the length with no load at all. When you put the weight of the mill on them, they get flatter and longer. The purpose of the hangers(that's the term I couldn't think of before :

) is to allow them to get longer. Now, if you're going down the road and hit a hump in the pavement, or a railroad crossing, the springs have to lift the mill over it, and that will cause them to flex...to get flatter and longer. That's well and good, but what if you were going a bit faster than you should have, and the wheels come off the ground as you bounce over the hump? Suddenly, you have the weight of the wheels and axle pulling the springs the other way, making them shorter than "normal." This is the point at which you do not want the hangers to be hanging forward of vertical. If they are, when the trailer comes back down, which it has to by law, the hangers will take the first strain and tend to continue in their forward arc. This will prevent the spring from lengthening and cause it to bind, which will either break something or bend something, as Gary said.

Judging from your photos, which are excellent, I'd vote for placing the rear shackles an inch or so forward of the "normal" length of the spring. Your hangers are plenty long enough to give the spring room to roam to the rear. You just don't want them to roam to the front.

firecord · May 22, 2007, 10:23:05 AM

Wow learned something new about northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company. Never bought from them, just get their catalog at work. DanG, I couldn't have said it better myself.

bedway · May 22, 2007, 11:39:22 AM

Seems theres a concencus that the pivoting hanger should be forward of verticle when the spring is not under load. Im going to reclamp the rear hangers forward, then jack it up again and take a pic. Ill report back shortly. Oh, thanks for the comment about the pics dang, i got some help on that ;D

bedway · May 22, 2007, 01:28:21 PM

Well i just came in for a sandwich and to load the pics of the aforementioned exersize. Dang, i sure wish i had put the memory chip back in the camera b4 i took those picks. The pics are on the internal memory of the camera which i cant access to this computer. Well, chalk that one up as todays minor diversion :D.,,bedway

jrokusek · May 22, 2007, 05:19:22 PM

Can you use some overload springs? We had some a long time ago that literally "bolted" to the existing springs. They didn't engage until the springs squatted to a certain point and then engaged. Lord help me for posting a link to JC Whitney

aniakhenry · May 23, 2007, 12:34:36 AM

OK, I have only skimmed the arguing points of the springs and am not too interested, but...

Here is the bigger question, is that a procut sawmill your building there?

bedway · May 24, 2007, 08:20:49 PM

No, its not a Procut sawmill. I bought the saw head complete carraige kit from Linn Lumber. Ive been building it since last november in my spare time. I have lots of pics in my gallery of my progress. Ive been very pleased with the design and materials that came with the kit. I have made some modifications to suit my own needs and likes. Im hopeing to be within days of makeing sawdust ;D,,bedway