A Real Dirty Job

Where users can chronicle their builds. Start one thread and continue to add on to it.

Moderators: Harold_V, WJH, hwboivin3

User avatar
Carrdo
Posts: 1008
Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Thu Nov 08, 2018 6:19 pm

No new incidents to report.

The first leaf spring bundle assemblies. They are not finished yet but I am getting there.

I don't know if I like the leaf springs with the spacers or not. Will at least try it out and see how it works.

I do know that without the very fine control on the bench rollers, this would not have been possible as each leaf except the shortest two (top) spring leaves are curved slightly more than an adjacent leaf. I tried to make the curvature on each leaf such that when two leaves were set together without a spacer, if one pinched the two leaves at one end, the gap at the other end was equal to a leaf thickness (0.015").

You really can't see this feature with the spacers in place.

I also noticed another issue coming up with the Langworthy design regarding the above but I will deal with it shortly.
Attachments
201 The Leaf Springs First Assembly into a Leaf Spring Bundle.jpg

User avatar
NP317
Posts: 1445
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: A Real Dirty Job

Post by NP317 » Thu Nov 08, 2018 8:14 pm

I do not understad how that spaced leaf spring would work.
Normally, the spring functions by adding each leaf force as the spring is compressed.
Those spacers prevent leaf interaction, leaving the longest leaf to do all the work.
~RN

User avatar
Carrdo
Posts: 1008
Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Thu Nov 08, 2018 9:27 pm

NP317,

Yes, you are correct.

As I mentioned, this was the first setup.

There was a reason for doing it this way. I needed to know if I hit or missed another required dimension which was shown on the Langworthy drawings and this was the setup which would tell me. Yes, I did hit it or am very close.

The final result (most likely) will be the metal spacers will be replaced with a lot of dummy plastic leaves (to keep the dimension which I was trying to hit) or I am going to have to make a lot of additional curved spring leaves. The spring leaves were made curved, one slightly more curved than the one above, to try and make them "progressive". If I put in all those additional metal leaf springs, over what Langworthy specified, there will be no spring at all.

I simply don't know at this point as I really need to find a practical way of determining the actual weight which is on the locomotive lead truck, the drivers and on the trailing truck (and I don't have such a method). I suspect that virtually 100% of the locomotive dead weight (in 3/4" scale) is on the drivers and that the lead truck and trailing trucks are just going along for the ride but I can't prove it. The Langworthy lead truck dead weight is only 5 lbs.(and add another 15% for vertical impact loads - my guess) and if that is all the weight the lead truck springs will see then yes, the first two leaves are all that one needs to be working.

Otherwise, it is all just so much trial and error (so one needs to find a very flexible spring design/arrangement).

User avatar
NP317
Posts: 1445
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: A Real Dirty Job

Post by NP317 » Fri Nov 09, 2018 12:31 am

Now I understand what you were doing.
Thanks.
~RN

Post Reply