Building the Southern Railway PS-4 Frame

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mjahn
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Re: Building the Southern Railway PS-4 Frame

Post by mjahn » Sun Sep 11, 2011 11:42 pm

Guys, you can save yourself the time of grinding down a drill bits (at least on some sizes) by using Dewalt bits from home depot. They have some TiN coated ones that are flat around the perimeter and have a bit of a pilot in the middle. They worked great and even withstood my abuse reasonably well :)
Mattaniah Jahn

Matt Corps. Railsystems,
operating on the Manatee Central RR
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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Wed Sep 14, 2011 4:35 am

Received the endmills and counterbore bit from ENCO, also managed to get my hour in the shop last night.

Wife is starting to wonder about the number of ENCO packages coming in the door.

Finished cutting all six pedestal binders down to 5/8 x 3/4 and cut to length last night.

Now to drill and counter bore for the bolts
DSC_0138.jpg
Charlie Pipes
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2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Wed Sep 14, 2011 8:37 pm

The six binders are finished except the future drilling for the horizontal dowel pin. They have been added to the Kit Pile
DSC_0140.jpg
Using the counterbore bit without asking advice, along with having read comments about breaking them, I decided to run it very slow with a lot of oil on it. Seemed work nice at the lower speed.


As much as I would like to tackle the frame sides I believe I will do the brake Fulcrum (Not sure this is the right name here) next as it is made from plate and not a big loss if I mess it up. Needless to say my learning curve is still large before me.

Working from the Fitt Drawings and this photo I downloaded off the internet I was able to come up with a fabricated part that would not require a casting and be simple enough that I could tackle it. It will be cut from four pieces of hot rolled 3/8" and bolts into the frame using the scale bolt holes.
401 Brake Fulcrum Model (2).jpg
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2479FrameBrakeFulcrum2.jpg

kvom
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Re: Building the Southern Railway PS-4 Frame

Post by kvom » Thu Sep 15, 2011 7:31 pm

Minor comment on the above plan:

You do not specify a radius for the arc that joins the R.4514 arc, which would make anyone trying to make this to plan have to guess both this value and the center of the dimensioned radius.

It's also missing X datum position for the first of the 3 tapped 8-32 holes.

Since the right and left plates are the same with opposite hand, it might be clearer to use one larger drawing with all the dimensions.

Looks like a good place to start. If you bolt two pieces of stock together it seems you could machine both plates at the same time.

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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Fri Sep 16, 2011 4:48 am

You do not specify a radius for the arc that joins the R.4514 arc, which would make anyone trying to make this to plan have to guess both this value and the center of the dimensioned radius.

It's also missing X datum position for the first of the 3 tapped 8-32 holes
Thanks for the look. I can not tell you as a beginner how much I appreciate having someone who has "done it" to take the time to look over my shoulder.

Did a quick fix on the drawing last night and have the HRS laying on the saw to cut the four blanks for the project.

As to bolting them together I figure this is the best way and will give me practice with the method prior to working on the side frames.

I am giving second thoughts to the radius used on the drawings. They are simply scaled down from the Fitt Drawings. I am wondering if changing from .5333 to .5000 would make it easer to machine as I could then use a standard tool size. Is this common practice?

Thanks again for your input KVOM.

Charlie Pipes
Charlie Pipes
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2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
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kvom
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Re: Building the Southern Railway PS-4 Frame

Post by kvom » Fri Sep 16, 2011 6:58 am

To machine all these external radii accurately without a CNC mill you would need mount the plates on a rotary table with the center of the rotab on the center of the arc. So the size of the tool will only matter if it's an inside radius. Sine you have access to the drawing on your computer, you can find the centers of the arcs. Someone else using your plan would have to calculate them (if possible). So I would recommend giving the coordinates of the arc centers on the drawings.

Of course you could just print a full-scale drawing, paste it to the metal, and then saw/grind/mill the profile using the #1 eyeball.

On the brake fulcrum bearing, how were you planning to machine the top radius inside the flange? Since it's not seen you might want to do something easier (e.g., make the profile square and the slot to match). Although it's possible to calculate the flange depth and hence the top radius, why not specifyit directly?

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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Fri Sep 16, 2011 6:01 pm

I spent my lunch time re doing the radius for the use of standard drills and cutters. As you say I will probably transfer the lines for the outside curves and cut to the line by the TLAR standard.

I will go back in and lay out the reference marks for the center of the radius.
Charlie Pipes
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2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Sat Sep 17, 2011 7:11 pm

Trying something new with the drawings. I have printed them out on letter sized paper to work from. they sit nicely on the table of the mill.

Cut the plates to size with my cheap Harbor Freight Bandsaw which I am beginning to loose faith in. It has made less than a dozen cuts and is slowly beating itself to pieces. Looks like it may a rebuild job in itself.

Managed to break two blades on a bandsaw this afternoon cutting the plates into usable size. Off to Huntsville next week for new blades. Hope to find some of quality and not the stuff I found at Harbor Freight.


After bolting the plates together I started fly cutting the parts that make up the side of the assembly. (Question for the day: How deep a cut is normal when fly cutting and are blue chips ok?)
DSC_0169.jpg
Also continued moving equipment and getting the shop cleaned out for this as a dedicated project.
Charlie Pipes
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Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
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Fender
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Re: Building the Southern Railway PS-4 Frame

Post by Fender » Sat Sep 17, 2011 7:25 pm

Blue chips are OK for carbide, not for hss. Yellow chips are about as fast as you should go with hss.
Depth with the flycutter depends on the mill, but I usually don't go more than .020 or so. I use the flycutter to finish, not to get to size.
If you set up a shield in front of the workpiece, the chips won't go all over the workshop. But then, you have that magnet thingy....
Dan Watson

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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Sat Sep 17, 2011 9:04 pm

The magnet is great. Hot chips up the nose or in your mouth kinda suck real fast. I am digging around the shop for some plexiglass to make me a couple of shields.

Oh, if you use the fly cutter for clean up what do you cut to size with? Bandsaw

Thanks for the info.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

kvom
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Re: Building the Southern Railway PS-4 Frame

Post by kvom » Sun Sep 18, 2011 7:34 am

Your photo looks more like a face mill than a fly cutter.

A good bandsaw blade will help a cheapish saw work a lot better. Get a bi-metallic blade with enough teeth/inch so that when cutting you always have at least 3 teeth in the material. Also make sure that the SFM is not too high (should be around 80 for mild steel).

I use a bandsaw to cut stock to rough size, and then an endmill to square up the edges. For the flat faces of the plate I use a 2-insert 1.25" facemill; usually I take around .025" DOC at 8ipm or so, and blow the chips with air while cutting. I take off the same amount on both sides to reduce stress warping. The steel I get locally is typically slightly undersize, and by the time I mill the surface flat it's .01-.02" under nominal size. So if I need an accurate 1/2" thickness, I use 5/8" steel to start. Obviously the closer to final dimension the stock is, the less time you spend in preparatory machining. Lengthwise slicing is impossible to do on a horizontal bandsaw and a PITA on a vertical, so it's best to get steel in the width close to what you need. With brass lengthwise slitting using a slitting saw on the mill works for me, but I haven't had good results doing that with steel.

To avoid chips in the face at the Bridgeport, I feed right to left and cut back to front (conventional cut), so that the flutes send the chips to the back of the table.

Hope this helps. Others may do things differently.

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Pipescs
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Re: Building the Southern Railway PS-4 Frame

Post by Pipescs » Sun Sep 18, 2011 8:30 am

Motivation Photo of the Day

PS-4 Pacific No. 1401 at the Smithsonian
Second trip (69).jpg
I can see that the completion of this project will require all the dedication and perseverance I have.

I am cleaning out the shop and giving away large numbers of RC model airplane items to keep me on track over the next ten years.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

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