Wagon springs

[Wayne]

Hi all,

I have recently acquired an old market barrow and judging from age etc I am thinking its pre WW1 possibly turn of century.

It's in a pretty ropey state. So is a question of try and salvage as much as possible or use it as a pattern for a new build?

My main question is regarding the springs it is mounted on, they are elliptical and really rusted and pitted and as yet I have not had chance to run file over to test hardness.

The bottom spring is curved with both ends forged with two lugs, these are drilled for a bolt. The opposing spring has the ends rolled for the bolts to pass through.

Each spring has two smaller springs mounted on the back, each smaller than the other, the ends of these springs are forged to a thin taper to flow in.

A hole is drilled through the center of each set of three and a fixing bolt holds each set together, two other holes one each side of the central bolt passes through each set to fix to the body and to the axle.

I am wondering if with all the forging and drilling if these springs are really spring steel ie en34 or something softer like en13?

Diderot shows springs on carriages in the 1700's but again is this spring steel as we know it?

Does anyone have any knowledge on spring production prior to the 1900's?

Thanks

Wayne

[Frosty]

Wayne: Where are the pictures? You've been a member long enough to know we LOVE pics. Heck, if we can get a gander at what you're talking about we might have some ideas and maybe folk who don't know what's what will not post their ideas.

Frosty The Lucky.

[ThomasPowers]

Willie White once told us at a Quad State Demo that 100+ year old wagon seat springs were one of his favorite steels for making knives.

[Michael Cochran]

I too would like to see pictures. I love stuff from 100+ years ago be it iron, wood, tools, etc. There's just somethin about stuff from back then that has attracted me to it for years. Might be cause so much was made by skilled people who took pride in their work instead of things made by machines with no heart and soul to put into the work like it is these days.  

[Charles R. Stevens]

New ones are avalabel, this is the carcase of an older Amish bugy but they are still in production. 

 

[Wayne]

Hi Charles

The springs are just like that and come in at 27" long by 7" deep.the metal is 1 1/2" by 1/8, I say metal as I ran a file over them and it just bit straight in. I tried six or seven other places with the same result so it is not what we would probably class as spring steel hence my query.

The barrow is just a two wheel job, the wheels or whats left of them being around 30" dia. All the metal fittings are there its just the woodwork that is pretty shot. The body is about 4' by 3' by 9" deep.

When they stop messing with the phone cables in the village I can post some pics. Till then I am using my mobile at work.

I just wanted an interesting project....

Wayne

[Charles R. Stevens]

Well some one your side the pond makes springs for carts and buggys i'm sure, unless your masichistic enugh to forge your own, might surprise you what your local spring shop might get up to.  Carts came in an amazing veriaty but now adays I thing the waggons and carriages outnumber them.   

[Frosty]

A file will cut a modern car/truck spring easily, that's not an indication of steel type, only hardness. If a file skated on a spring, the spring would probably break early in it's life.

Frosty The Lucky.

[Wayne]

Hi Frosty

Stupid of me to ignore the obvious, just suprised how soft the metal is.

Charles, I am looking around but pickings seem to be slim this side of the water so far. But for a hand barrow which will not carry people or any great load I am just daft enough to have a go myself.............. maybe.

Wayne

[Charles R. Stevens]

If you do, talk to the Knife/sword guys on an even heat treat, sorce somthing like 4060 or other good spring stock, heat treat them use a press to set the arc. I have seen several rhat looked like the simply had turned an eye kn each end of one pack and the. Welded grade 8 washers to the ends of the others befor riviting them together. 

Otherwise, lets explore, some one makes visa vies, some one maintaines the Queen's carages, some one builds reproduction Vardoes and caravans. Bet a bit of work on the phone calling spring shops (y'all still belive in fixing things) should turn up some one to do the work. 

[Wayne]

I have the local paper shop getting me a copy of the Carriage drivers magazine, I figure that would be a good start.

Did not think about welding washers on, I was more thinkingthinking of jumping up ends of stock to give me mass to forge a couple of lugs, would need to watch I did not turn them up too fast and get cold shuts.

[Wayne]

Finally got the pictures sorted for the cart springs I aquired

[Charles R. Stevens]

Nicely fited. You can see wher the washers where jumpwelded on, but with modern spring steels, pre heat and weld with your faverite 7xx rod should be just fine. 

 

You can see that this set uses tubes with washers welded on the end, then welded to the springs. 

Edited October 5, 2015 by Charles R. Stevens

[gote]

You did not ask about it but I cannot help myself. I must show off what i have learnt.

There is a good reason why the spring is made up from blades each one shorter than the previous. In this case a main blade with two more.

The spring is subjected to a bending moment and a shear force. The moment is zero at the far end and maximum at the fixed end – in this case the middle. If you want to keep the resulting stress in the blade constant you need to make the spring triangular; wide at the fixed end and tapering towards the other. This is impracical so the theoretical triangle is cut into strips and these put on top of each others. The result is the spring you have. The three blades would make up the triangle if laid side by side. The result of this design is that the stress, caused by the bending moment, is nearly constant in all three blades over the whole length.

If it were only the bending moment, the spring could be very thin at the end. However, there is also the shear force to take up. Unlike the bending moment, the shear force is constant over the length of the spring and material able to take this force must be added. For that reason the main blade usually is sturdier than the triangle would call for. At the same time this gives material enough to shape the ”hinge” at the end.

I hope this was not too boring and bemuddled

Cheers

Göte  

      

[Charles R. Stevens]

Gote, a wonderful explination of spring theory. We americans are cheap/lazy buggers

Mobile/manufactured homes have been using taperd springs for years. As have some vehichicle manufacures, in either steel of fiberglass (crysler mini vans) tho trucks still use the "old method" I would imagine it has many advanteges over the "cheap" salution offerd by manufacturing technoligy. 

[mike-hr]

I find piles of old buggy springs at auctions for cheap. I cut the tapered ends off at about 8 inches, they made wonderful tapered wedges for layout, fabrication, and general millwright work.

[WL smith]

Gote sir I have always been told that leaf springs do not flex in the center section of the leaf. Have I been misled? 

[swedefiddle]

Good Morning,

Leaf springs don't move very much, where they bolt to something, in the middle. That is because that area is the thickest and the closest to the pivot point (the center of the axle). Watch a spring under compression, the Eye end is only the Main leaf, all the other leaves support the main leaf.

Neil

[Smoggy]

"...Leaf springs don't move very much, where they bolt to something, in the middle..."

You may want to quantify that Swede, I've seen elliptical leaf springs flex past the plane of the end mounting points......so it was the ends that didn't move much!

[gote]

I did not even get a forbidden this time

The cart springs Wayne have acquired are fully elliptic springs. The spring you find on an old car or truck are half elliptic. Old Bugattis had quarter elliptic on the rear axle. In all cases, the leaves are bolted together in the thickest point which in the case of semi-elliptic or elliptic spring is where the axle is fixed. Everywhere, except there, the leaves rub against each others when the spring flexes. Since there is some kind of plate holding the spring at the middle the spring cannot flex where the plate is but the flexing starts just outside the plate.

You all know that if you hold a flexible bar in the vise and bends it, it will bend most at the vise and not at all at the end. The end moves but does not bend. When you deform the bar it will bend permanently at the vise because the bending moment is highest there.

The whole idea in leaf spring design is to distribute the material in such a way that the stress is uniformly distributed so no part is subject to more stress than another. The result is that the spring always follows a circle. When it flexes, it flexes uniformly so the bending radius is everywhere the same. This is flexing due to bending. We cannot follow this principle exactly because we have a uniformly distributed shear force on top of the moment and the main leaf is made thicker in order to take up the resulting stress. (or there is a second leaf of the full length). This way there is also material available to make up the eye.

For this reason the spring actually bends less at the ends.

Yes a spring that is designed well bends most in the middle and less at the ends but the difference in radius is not great.

I hope this is clear. English is not my native language you know

Göte

[Charles R. Stevens]

Very clear. Your english is better than most native speakers, ya'know ;-)

[gote]

Thank you Charles