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Subject: 
Re: Universal Joint Modifications for Train Applications
Newsgroups: 
lugnet.technic
Date: 
Sat, 8 May 2004 22:21:24 GMT
Viewed: 
1578 times
  
In lugnet.technic, Luis Hernández wrote:
   In lugnet.technic, Mark Bellis wrote:

   For those unaware, a Shay engine has a 3-cylinder engine hanging over one side of the loco with jointed extending shafts running the length of the loco to 2 or 3 bogies. In principle this requires 6 uni joints and 3 extension devices. The problem with the Shay is to get the flexible transmission into a very short length (I’m aiming for 8 studs or less), yet extending and contracting by 2.5 studs as the bogie turns.

Any ideas for alternative solutions that fit the above spec are most welcome.

Mark Bellis

For what I can read, it seems to be a good use for the broken u-joints (yes, they are toooooooo long)... but, can we see the piece modified? It may help looking for an alternative solution. An also, where can I see a Shay engine? I’ve never heard about it.

Thanks a lot,

Luis
(comments, instructions, death threats, etc. please remove all the X’s)

There are pictures of Shays at:

http://www.cassrailroad.com/locos.html

Shay #6 is the one I’m building a model of, as its wheels are bigger than on most others (4ft rather than 3ft), so the BBB wheels (3’9” in 8mm:1ft scale) fit better.

So far I cut up 6 5L axles into 3.5L and 1.5L lengths. The 3.5L ones are used for the wheels that have 20 Tooth bevel gears on them - they need an extra 0.5L of axle to hold the bevels and are held in the bogie in an axle extender, with a 3L axle the other side for the other wheel. The 1.5L axles are used on the transmission shafts. Conveniently, there are 6 3.5L axles for the 6 wheelsets and 6 1.5L axles used 2 at a time on the transmission shafts - 100% utility of modified parts.

A uni joint with one end modified is about 3.2L long, having lost 0.8L of axle holder at one end. Sorry, no digital camera yet :-( The unmodified end has a 1.5L axle to hold a 24mm pulley for the extending part of the transmission. The modified end has a shorter piece of axle, modified with a thin round end like flex tube, to go into the 1/8” hole.

I have to take account of clearances when judging what length of axle to modify for the modified end of the uni joint. I’ll have to calculate how much I can remove from the total length of the transmission and still get it to work.

Mark



Message has 1 Reply:
  Re: Universal Joint Modifications for Train Applications
 
(...) Hi Mark, I built the bogie using unmodified axles but as you can see the drive shaft is just hangin in the breeze currently. (2 URLs) ROSCO (20 years ago, 9-May-04, to lugnet.technic, FTX)

Message is in Reply To:
  Re: Universal Joint Modifications for Train Applications
 
(...) For what I can read, it seems to be a good use for the broken u-joints (yes, they are toooooooo long)... but, can we see the piece modified? It may help looking for an alternative solution. An also, where can I see a Shay engine? I've never (...) (20 years ago, 7-May-04, to lugnet.technic, FTX)

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