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Post by IronMan on May 20, 2004 18:21:26 GMT -5
Hi, I have put the springs I purchased on the trucks, They are .500 o.d. 1.750 long the wire is .062. It is not going to work, not enough tension. I uploaded 2 pictures in the photos section. This is the front truck, with 8 springs like Kozo suggests, I wanted to save Myself some trouble and bought the springs, obviously not a good choice. Now there is 2 things I can do research the same springs with thicker wire or make them. Does anyone know how much deflection a real tender has? when fully loaded? or what a model should have ? Does anyone know anything about springs? what guage of wire should I shoot for?? I made a modification to the upper bolster, the thickness should of been 1.187 I had the option between going to 1.250 or to go down to 1" which I did, It should not affect perfomance in anyway. The material was easier to obtain, so it was a no brainer. Well I hope this will be of help to someone thinking about building in 1.5" . Regards, IronMan  |
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Post by DavidT on May 20, 2004 19:41:00 GMT -5
On the website for Cannonball Backyard RR's www.backyardrailroads.com they have springs that are rated by pounds to compress 1 inch. Most of them are 5/8 dia. |
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Post by IronMan on May 21, 2004 8:14:08 GMT -5
Thank you David,
I can not access the site for some reason. I am using 1/2 O.D. imposible to fit anything bigger. What I must need to do, is figure out how the compresssion works, guage wire size,how many turns etc what the springs will bear for load. I did some real quick research I have compression springs on, what about die springs? anyone knowledgeable on the subject?
Thanks,
IronMan
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Post by DavidT on May 21, 2004 11:11:48 GMT -5
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Post by IronMan on May 21, 2004 11:37:59 GMT -5
Thank you,
I have found the formulas in Machinery's handbook for spring loads. Finding them and using them is 2 different things. I will eventualy "get it " I suppose , I will post my findings on what I am going to use and the load it will take. It is a bit of a draw back for the moment but the tender is going no where soon.
Regards,
IronMan
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Post by phill3006 on May 22, 2004 1:06:20 GMT -5
g'day ironman
if you are talking about die springs as in injection moulding die return springs.there are different types off springs as in the material used.some use the round bar as the material used.they also make a spring out of flat material which will give you better travel as well as alot less chance of breaking.we use the flat type to replace any springs that have failed during the course of there life and find we get less failure with this type of spring remembering that i can run some dies for weeks on end non-stop.i find the flat type alot more reliable as you can close them totaly without breakage.which also means you can get more working spring in less space
regards phill3006
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Post by Bill holland on May 22, 2004 13:31:24 GMT -5
Use more springs  |
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Post by Bluechips on May 23, 2004 1:46:54 GMT -5
It is probably made from "inferior" wire, ie; not industrial spring grade. You can try to purchase springs made with heavier gauge wire or use the material that Kozo suggests. I'm not sure what constitutes scaling up in springs, probably doubling the area of the cross-section of the wire is not sufficient as the sprung weight increases out of proportion to the scale???
Good luck with this one! Let us know what you find.
Bluchips
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Post by phill3006 on May 23, 2004 5:24:35 GMT -5
g'day boys
ironman send me the size of your springs so i can do some homework on them for you as i said i work with these in our tool design so i maybe able to help with your problem
regards phill3006
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Post by IronMan on May 23, 2004 10:16:49 GMT -5
G'day Phill,
Thanks for the offer , here it is .500 O.D. X 1.750 and wire dia. is .062. I can not use anything bigger than .500 O.D. I have posted 2 pictures in IronMans A3 Photo folder that shows how much deflection the front truck has already with just the frame and the copper sides, there is 8 springs on that one , the rear truck has 12 and only a bit of deflection. In response to Bill's sugestion, even if I were to add more springs, which I may have to do, at least one series on each truck. It will never be enough to compensate for the weight. I can not put springs all across the bolsters. The solution is to make or find something with more tension. Die springs seem to be " stonger" just by the looks compared to regular tension springs .
Thanks, Bluechips for the encouragement I am sure between everyone here we will get to the bottom of this problem and find a solution. I guess these problems are all part of growing up!
Cheers,
IronMan ;D
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Post by patyoung on May 23, 2004 14:02:51 GMT -5
Hi Ironman, I remember reading somewhere about guidelines to use to scale up and found that Kozo provided some in his Shay book. If you plan to roll your own coil springs, he stated that the wire size diameter should be multipled by a factor of 2.56 and the spring diameter by 2.14 when building a 1 1/2 scale locomotive. Here is a transcript (from page 168): 3. Coil Springs The wire diameter of the coil springs should be determined by calculations, using the factors given in Table 3. The relationship between the deflection and the wire diameter is geometric but not arithmetical. A coil spring with the wire diameter calculated with the multiplication factor in Table 1 will be too weak for the larger scale Shay. : : TABLE 3 MULTIPLCATION FACTORS FOR COIL SPRING WIRE DIAMETER Scale= 1" Gauge= 4 3/4" Factor = 1.46 Scale= 1" Gauge= 5" Factor = 1.56 Scale= 1 1/2" Gauge= 7 1/4" Factor = 2.49 Scale= 1 1/2" Gauge= 7 1/2" Factor = 2.56 I would guess that this would also apply to store bought springs also. Hope this helps. Pat Young Cupertino, Calif |
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Post by IronMan on May 23, 2004 15:11:07 GMT -5
Hello Pat,
Thank you for the information, it gives me something to go on, by those calculations I would need about .100 wire, I will see if I can get store bought springs at a resonable price, or if I will need to make them. I will wait and see Phill is going to give me some information on die springs. Right now I need to figure out the approximate weight of the tender, and the total weight including me. It will give me an indication of how many springs I will need. But I figure if Kozo suggest to put 12 -8 he must of done the calculations before. I hope this story will come to a happy ending.
Cheeers
IronMan ;D
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Post by Bluechips on May 23, 2004 15:21:54 GMT -5
Phil's suggestion is an excellent one. The die springs would be worth trying especially if you come close to the optimum diameter of wire. Try Mcmaster Carr or your local tool and die supply house. Stay away from the hardware store variety.
Marcus
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Post by IronMan on May 23, 2004 15:37:03 GMT -5
Thank you for the help, it would appear that my enthousiasm got the best of me, I should of done my homework before hand, I did buy hardware store springs. I was there one day and I saw them..... Well if my mistake can save someone else, the trouble it will of been for some good.
IronMan
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Post by phill3006 on May 24, 2004 5:02:33 GMT -5
g'day ironman
the hight of your sping i assume is 1.75 inch is that the area you have to work with as in when the spring is removed the area where the spring sits is 1.75 inch if so remember you can have some tenshion on them when you insert the spring so if your max opening is 1.75 inch you can use a spring of greater size.as a car spring you need to close them alot to get them in.i will need to know the opening and the amount of travel so i can work it out and i will get back to you asap
regards phill3006
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