It is currently Sat Nov 18, 2017 11:50 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Tue Oct 06, 2009 12:07 am 

Joined: Fri Jul 25, 2008 6:34 pm
Posts: 26
I'm looking for three of the pictured component from a Heywood-Wakefield walkover seat. It supports the seat cushion and allows it to move when the seat's direction is reversed. This part has 68244 cast into one side. It's 16.25" overall. The pins that hold the seat cushion in place are 10" o.c. Please email me directly at np5070@charter.net if you can help.


Attachments:
IMG_2649.jpg
IMG_2649.jpg [ 213.45 KiB | Viewed 1123 times ]
Offline
 Profile  
 
 Post subject: Re: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Wed Oct 14, 2009 12:39 pm 

Joined: Thu Jan 12, 2006 2:38 pm
Posts: 209
Location: Roanoke VA
NPaul,

If you have trouble finding these castings, have you considered recasting them? We have a local Foundry that we have railroad parts recast at, Cast Iron, Cast Steel, Cast Aluminum and I think some cast Brass. The reason I mention this is the part is relatively small and looks like the part it's self could be used as the pattern given its shape. My guess you could have rough castings in hand for I'm guessing $30 or so Dollars each. Just an idea if you can't find any and it might be holding up that project.

_________________
Steven Smith
Roanoke / Salem VA


Offline
 Profile  
 
 Post subject: Re: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Wed Oct 14, 2009 2:06 pm 

Joined: Mon Apr 30, 2007 12:45 am
Posts: 442
Location: Illinois
The main problem with using a mechanical component as a direct pattern for duplication of itself is shrinkage. Due to the temperature of the molten metal when poured, the finished part is roughly 3.5% smaller than the pattern used.

A proper pattern is made 3.5% oversize, so that the shrinkage results in a properly sized part.

Jeff

_________________
What if we took a GG1 and changed...?
Image
Image
I'd rather be a NNN, than a Yammering Yutz of Yesteryear


Offline
 Profile  
 
 Post subject: Re: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Thu Oct 15, 2009 12:25 pm 

Joined: Thu Jan 12, 2006 2:38 pm
Posts: 209
Location: Roanoke VA
Jeff,
While I welcome your comments, We (Our various Local Preservation Groups) have be making patterns, casting and manufacturing parts for our railroad equipment for decades. Now I will say you do bring up a valid point with making most parts but there is so much that can be done taking shrinkage and other material aspects into consideration. To us this is a simple part (Bracket) that when cast properly would yield parts that would look and work just fine for needed application, yes there would need to be some machining to dress up and shape the casting but operations wise it should still function as designed. Now once you do get into what would be considered more critical mechanical parts there are many variables to consider with shrinkage being one of them.

I still feel that casting duplicate components if handled properly off an original is a valid option for this application given that original components remain unavailable.

In my free time I volunteer for local preservation groups, To pay the bills I'm an Industrial Engineer dealing primarily with Research & Test and Material Science for a Class 1 Railroad.

_________________
Steven Smith
Roanoke / Salem VA


Offline
 Profile  
 
 Post subject: Re: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Fri Oct 16, 2009 1:42 am 

Joined: Fri Jul 25, 2008 6:34 pm
Posts: 26
So that my wife (who's my partner in this restoration) will stop giving me grief- I hereby apologize for the billboard-sized photograph attached to my original message. I'm better with tools than with a computer! ...now perhaps I can sleep in the house tonight. :)


Offline
 Profile  
 
 Post subject: Re: WANTED: Heywood- Wakefield walkover seat component
PostPosted: Mon Oct 26, 2009 1:49 pm 

Joined: Sun Oct 10, 2004 3:45 pm
Posts: 165
Location: Hudson Valley, NY
Uh, 3.5%? Like the commercial says, "not exactly..."

Different metals/alloys have different shrinkage ratios.

http://www.nonesuchtools.com/pmkr/shrink.html
(If you're not familiar with basic foundry/patternmaking, poke around this site - some good stuff is listed, including suppliers).

Proper patternmaking utilizes "shrink rules" -- customized rulers that provide the appropriate compensation for the specific casting material, without causing the patternmaker to fry his/her brain computing all the compensated dimension sizes while trying to make a pattern. Such items are usually available from a foundry supply house.

_________________
John Isaksen


Offline
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 5 hours [ DST ]


 Who is online

Users browsing this forum: RBH and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: