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Building the Southern Railway PS-4 Frame

Posted: Tue Sep 06, 2011 9:28 pm
by Pipescs
For the last year or so I have been involved with members in what started as a discussion on the PS-4 Pacifics used by the Southern Railway. (Not the Southern Railroad as I was enlightened early on)

Having started a LE American that my heart was not really in, I have always really wanted to build a Pacific. Thanks to all those who had input I have put the LE American back on the shelf and convinced myself that I could tackle the PS-4.
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This is the first thread of what I hope to be a ten year or less build. The kick off came as I realized that Monday was my Sons 15th birthday. I am 57 and have come to the conclusion I need to get on with this project before my health record runs out. The goal is to see my son run it on his 25th birthday. As threads can run on forever and become hard to read I am going with short stories. This one is to encompass the frame and some of the crossties.

Having moved up from my motorized paperweights (as my friend Larry Kombrink calls my small mills and lathes) I have started with some of the simpler parts of the frame. I am also cheating in that I have a young friend in school who has asked for a few drawings to convert to CAD so that he can cut the parts and get a grade for them. Needless to say I will continue to be asking for help and guidance

NOTE: If you see me starting down a dumb path, please pull me back from my own ignorance.

My first project at home is the Pedestal Binders.
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201 Pedestal Binder  (2).jpg
NOTE: As asked before, no I am not working to these tolarances. I simply am too lazy to reset my AutoCAD to show less decimals

First Cut
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The frame having already been cut by Teddy Love out in Las Vegas is 3/4 HRS. I cut six blanks for the Binders from 3/4 HRS bar stock and am off and running. Hoping to have them done before my next trip.

Once again thanks to all the people on line here that have motivated and convinced me I can do this.

Re: Building the Southern Railway PS-4 Frame

Posted: Tue Sep 06, 2011 9:46 pm
by mjahn
Congrats! Building what you love is a wonderful journey! :D

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 2:22 am
by VO4454
You may want to consider using 5/16 socket head cap screws through the binders and threaded into the main frame. It may prove hard to drop a binder at a latter date with all the brake rigging and the drivers in place, to get a wrench on the bolts or the nuts as shown in your drawing up in the lower frame rail. We used a single 3/8 SHCS and a 3/8 solid dowel pins in lieu of toes. No hi-jack intended with the attached pic, I'm just a show me guy rather than tell me. Keep on machining

Vic

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 7:22 am
by GN2114
I am going to agree with Vic, in that you need to decide right now if you are leaning toward museum quality with some running, or plan to run the wheels off it, with all the running maintenance that is part of live steam.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 8:22 am
by kvom
On my current build, I decided to limit the number of fastener sizes as much as possible. I used 10-32 for assembling the frame members, and 8-32 for everything else that would fit. I do have a few 5-40s as well. While I am using SHCS during the build, I will use model scale hex-head screws and nuts where I think they will look best. Since there is so much assembly/dis-assembly needed when fitting things, the socket head screws make this work go a lot faster.

Good luck with the project.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 4:09 pm
by hwboivin3
Glad to see the progress!


Make's me want to start on one!

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 4:30 pm
by Pipescs
No hi-jack intended with the attached pic, I'm just a show me guy rather than tell me.
This is not a Hi-Jack This is exactly what I need. It can become frustrating on a forum when you make an input and get no feedback. You just continue down the path right or wrong.

As you say it is one thing to build a museum quality model and another to build one that is Reliable and Maintainable.

I redesigned the Binders at lunch on the laptop and came up with this. I could not remember the size of bolts or pins you mentioned but redrew everything with 5/16 inch cap screws and .250 Dowel pins.
201 Pedestal Binderl (3).jpg
201 Pedestal Binder (4).jpg
No problem with the design change as I am still thinning the bar stock down to 5/8 inch. This also simplifies the prep of the frame as I can now fly cut the bottom rail down flush.

I am on the asumption that I will locate, drill and tap the screw holes in the bottom of the frame. Then after bolting the binders in place drill and ream the holes for the dowel pins in both pieces at the same time.

Question: Do you make the hole in the binder larger to be a slip fit over the dowl that I am also assuming is a press fit into the upper frame.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 6:23 pm
by Pennsy fan
One suggestion is to cut locking groves and not use pins. I have worked on plenty of engines and found that is a easy way to keep the frame in tram. Also taking them off and on is also better.

d.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 6:55 pm
by mjahn
I politely disagree on the pedestal tabs being of much value on the tramming issue. If you just put 2 .25" dowel pins on a slip fit in each side of that big cradle and then another 2 per side on a spreader up front you should keep tramming at bay, doubling the amount of pins per side would be better. You'll save yourself a good deal of time if you don't do the tabs, though the pins can be a bit of a pain if they aren't pressed into the pedestal binders very well.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 7:05 pm
by boomerralph
Congratulations on the start of your build.
I have a LE Pacific under construction, and am contemplating backing up and going the PS-4 route.
I've always been in love with the SR Crescent Limited.
You are an inspiration to me.
Thank You

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 7:22 pm
by Trainman4602
Hi

I mean no offence but using a vertical dowel pin is not the best method of doing it.

I have had great success using a dowel pin horizontally. A Dutchman pin if you will. I use the cap screws ¼-20 is plenty. I place a .005 shim between the keeper and the frame and then drill and ream a hole on the joint line. When completed I disassemble the keeper and remove the shim. The .005 smaller holes will “clamp” the dowel and give a tight fit acting like a key.

Here is a picture of Dan Horting’s K4 frame using my method.

Re: Building the Southern Railway PS-4 Frame

Posted: Wed Sep 07, 2011 7:28 pm
by Fender
I agree with Dave. I used the same method on my Davenport loco. With the pins in horizontally and splitting the frame and binder, the bolts will force the frame into alignment if the jaws spring open or closed a little. I'm a pinhead about using fine thread bolts, so the only difference is, I used 1/4-28 bolts.