Recommend Shapeways metal choice

[Greg_Lewis]

How about a recommendation on metal choice for these marker lamp brackets I'll be getting from Shapeways? I see either brass/bronze or steel. Of course, they'll be painted black but I'd like as smooth a finish as I can get without having them hand polished. THANKS!

https://www.shapeways.com/product/MXTHM ... quot-scale

By the way, Tom, the artist who drew these up for me, has several other parts that some of us could use. Check out his section on the Shapeways site.

[amadlinger]

Hi Greg,

I would highly recommend the "raw brass" or "raw bronze", both of which are actually investment castings; Shapeways prints the master on a high-resolution 3D printer and then investment casts the parts in brass or bronze. Attached are some photos of parts I have had made recently in raw brass, exactly as I received them from Shapeways with absolutely nothing additional done by me.

The steel and stainless steel options are excellent for larger parts, but the resolution isn't as good as the brass/bronze. With the stainless, they actually use the 3D printer to bind together powdered stainless steel, fire it in an oven to make it congeal into a structurally solid but porous part, and then infuse the porous SS with bronze to fill in all the porosity.

Sincerely,
Adam

[Fender]

What alloy is the raw bronze?

[Greg_Lewis]

THANKS Adam!

[Short Line Tom]

What alloy is the raw bronze?

shapeways_bronze.png (1.8 KiB) Viewed 5505 times

shapeways_brass.png (2.07 KiB) Viewed 5505 times

Cheers!
Tom

[Fender]

Thanks!

[amadlinger]

Hi Greg,

You bet! I am on the road heading to a Meet now so I don't have a great photo, but below is a Shapeways "stainless steel" brake hanger for comparison. A note of caution if you ever do use the SS. As others on the forum here have noted in the past, the Shapeways SS material is very difficult to machine. Brand new HSS drills didn't even want to touch it, but I used solid carbide tooling and it cut fine.

Happy modelling!

Sincerely,
Adam

[NP317]

Hi Greg,

[snip]
A note of caution if you ever do use the SS. As others on the forum here have noted in the past, the Shapeways SS material is very difficult to machine. Brand new HSS drills didn't even want to touch it, but I used solid carbide tooling and it cut fine.

This corresponds to our early research (2005-ish) at the Univ. of Washington Mechanical Engineering Department, developing printing with SS powder. I was tasked with testing the machinability of our bronze-infused SS matrix. It was indeed difficult to machine! Making small (< #10) threads was deemed nearly impossible with my "standard" machine shop tooling.
~RN

[Kimball McGinley]

to amadlinger: Where did you get that brake shoe?

[amadlinger]

Hi Kimball,

The shoes are from Howard Gorin, The Machinery Works. I like them because the shoes are separate from the body, just like the prototype, and the body has a bump out to install return springs, again per the prototype. I am using them on my 2-8-0 with 7-5/8" drivers, but a friend of mine used them very successfully on his LE Pacific with 10" drivers.

Sincerely,
Adam