Looking for steamer parts

[Chris333]

This is the crosshead from a MDC/Athearn 2-6-0 and 2-8-0



Just need the black piece. The same part from an Atlas/Microace 2-6-0 will work as well.


I'm looking for a bunch of these for scratch building purposes. Any ideas?

[Iain]

Etch the crosshead and use brass wire for the piston shaft?

[Lemosteam]

@Chris333 I could do that in Shapeways.  You can send me a part and I will model it and put it there with as many as you want.  I assume this has a right hand/left hand?

[Chris333]

John, I appreciate the offer. I know someone who is making a few other parts in 3D for me that could do it. But do you think FXD would hold up?  The upper part has to slide back-n-forth on a square metal shaft. I'm not so worried about the piston as the cylinders they go in would FXD as well.  That is a penny under it you know 

[Lemosteam]

Yep, I do.  Good radii in the corner or you could make the block and use a brass rod.

If the wall thicknesses and diameters are OK per SW rules, you could make it from Black Flexible which is a nylon base, and very slippery.

[robert3985]

I'd break out the dial (or digital) calipers, take all pertinent measurements and make this tiny part with jeweler's saw and files out of brass...or aluminum.

I'd find a piece of square rod (preferably) or round rod to start with which are just a bit bigger in all dimensions to your finished part, and file (or cut) this piece completely out, except leaving the last cut to separate the finished part from the rod...use the rod as a handle to hold the piece, then...after it's totally filed to shaped (except for the last cut), put the handle in a vice and carefully cut it off as close to the correct length as you can...cut slow...and use the whole blade of your saw in long, smooth strokes...

After it has been separated from the rod (handle) carefully vice it up and smooth your cut with your files.

Voila!  You're done, except for adding Archer rivet decals along the top and painting.

If you wanted a bit more realism it'd be fairly easy to make a metallic piston shaft from nickel silver wire (or rod), carefully dressing each end so they're burr free, then filing and shaping a separate end-piece (which is held in place between the two holes drilled in your crosshead out of brass...then insert the piston rod into this end-piece and solder in place.

If the rivet details are not important to you, then I'd file the crosshead up from black Delrin rod and use the stock plastic piston shaft.

This would be really easy if you had a mill and lathe (which I do)...and two of these would be done in a couple of hours.

I see no need whatsoever to either etch or 3D print this part....too much work for such an easy part to make.

Cheerio!
Bob Gilmore

[peteski]

Nice writeup Bob!  One problem: Chris said "I'm looking for a bunch of these for scratch building purposes. Any ideas?"
 

[Chris333]

Oh I wouldn't  mind making the parts. I do have a mill and a lathe. I just don't  think I could ever do it.

I've go ones on a kit that are etched, but they used nickel silver instead of brass.

[robert3985]

Nice writeup Bob!  One problem: Chris said "I'm looking for a bunch of these for scratch building purposes. Any ideas?"
 

Hehe...I overlooked that part!

Well...that's a whole different problem...but easily accomplished. 

This time, I'd go with Shapeways, but instead of expecting finished parts from them, I'd do the 3D modeling 10% oversized and design a "sprue" to hold half a dozen crossheads and pistons, with a small gate and receptacle on the opposite ends of each part...and order the parts in "Castable Wax".

When you get your prints, I'd take half a dozen sprues down to several local jewelry shops, or rock shops...to somebody that does jewelry lost-wax investment casting and see if they'd be able to cast your parts in nickel silver...and how much they'd charge to tree up a a "bunch" of them, invest them...and cast them.

Although I have the equipment to spin-cast my own flasks, my local rock shop charges me only 20 bucks to tree-up, invest, cast and de-invest the tree if I supply the metal...so it's a lot easier for me to just drop off a bunch of wax masters and pick up the brass parts a few days later.  An important question to ask them is "How old is your investment?"  If they are using old investment, your castings will be rough.  I actually offer to buy investment for my rock shop when I need a tree of brass parts since it's relatively inexpensive.  For the past few years, I haven't had to do that, and the parts have been flawless.

Since the guy who does my casting usually only does silver or gold pieces, we did a test run first with my brass material...and all worked out just fine. 

Depending on the size of flask they can use with their equipment, you could get several hundred parts in a single cast.

That's what I'd do if I were you...'cause it's what I do for the hundreds of parts I need for my layout's trackwork.

I have both a commercial vulcanizer and wax injector, so I have not used Shapeways yet, but I've got my eye on some complex parts and I'll probably do exactly what I've told you to do...but I'll be using the first investment-cast parts as hard masters to make my vulcanized rubber molds to produce wax masters for my rock shop to cast up...I just have to calculate the total shrinkage first.

Cheerio!
Bob Gilmore

[Chris333]

Bob,

Shapeways does brass   

I'm not 100% sure, but I think they print the parts in FXD and then cast them in brass for you. I might have to look into that.

[robert3985]

Bob,

Shapeways does brass   

I'm not 100% sure, but I think they print the parts in FXD and then cast them in brass for you. I might have to look into that.

They do.  However, I'm pretty sure it's going to be a LOT more expensive for them to cast them in brass than a local jewelry store/rock shop to do it for you.

But, if you don't mind the expense, Shapeways will do a fine job of it!

Cheerio!
Bob Gilmore

[rodsup9000]

  You could have them cast in white metal. What is the original made from?? The molds I use vulcanize at 300 degrees F and if the original part can withstand that temp, I could use it with about 1% shrinkage on the reproduced parts. I could do them for you, but it'll be a month or two before I'm going to do any casting again. 

[Chris333]

I like the idea of white metal. I'd want to make sure the original would survive though as it would cost about $60 to replace it.

[Chris333]

Has anyone had brass cast with Shapeways.

https://www.shapeways.com/blog/archives/2550-introducing-castable-wax-our-newest-maker-only-material.html

From what I've read they won't let you gang more than one part together. If so that is a bummer.

[up1950s]

Is it possible to modify a modern crosshead by filling the top of the top slot and grinding off the lower slot ?