USATC S-160 Consolidation

Where users can chronicle their builds. Start one thread and continue to add on to it.

Moderator: Harold_V

User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

The link motion support brackets are a couple more casting efforts. I cast the one on the right today. These are the biggest and most complex investment castings I have made. I had to split each of them into two 3D prints to fit my printer and then glue the halves together. They were cast in a 5" X 6" flask using vacuum assisted investment casting. The one on the left is actually destined to go back into the pot. I'm only allowing a 1/32" allowance on the machined surfaces and it doesn't allow much room for error.

There is still need some work needed to smooth the surface, but I don't have to feel too guilty, per the attached photo the prototype is pretty rough.

These and several other of my recent bronze castings use C9370 bronze from the chips generated when machining the new rod and main bearings on ARR #557.
Attachments
20201021_213054 reduced.jpg
link motion support reduced.jpg
Sandiapaul
Posts: 567
Joined: Wed Jan 07, 2004 8:04 am
Location: Princeton, NJ

Re: USATC S-160 Consolidation

Post by Sandiapaul »

Nice! What metal are you pouring?
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: USATC S-160 Consolidation

Post by Harold_V »

Sandiapaul wrote: Thu Oct 22, 2020 12:17 pm Nice! What metal are you pouring?
Last sentence in his post:

"These and several other of my recent bronze castings use C9370 bronze from the chips generated when machining the new rod and main bearings on ARR #557."

H
Wise people talk because they have something to say. Fools talk because they have to say something.
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

For bronze, In addition to the C9370 bronze shown above and home brew aluminum bronze, I have used SAE 660 and a couple of unknown bearing bronzes that have been donated to me. One was from a 6" ID bearing that probably came from the propeller shaft of a fishing boat. Another came from a bracket that contained a bearing surface from a piece of heavy equipment and both might have been SAE 660. I have also cast some brass from scrap, aluminum from scrap, and purchased ZA-28 ingot. Most of the bronze has been investment cast using 3D printed models in castable resin, although I have done a couple of investment castings with PLA. The other stuff was all sand cast in Petrobond.

The ZA-27 was probably the easiest to cast and gives nice castings. It casts at a fairly low temperature, is fluid, and gives a nice finish. It's supposed to have good bearing properties. One of the biggest drawbacks is it just doesn't look right on a locomotive. Although good structurally, I don't think it's good where it would be directly exposed to steam.

Brass was my least favorite because the zinc boils off, especially when it is overheated and the fumes aren't good for you.

The bronze casts OK, but the pouring temperature is fairly high and its harder to source the feed stock cheaply. Most of the bronze I have used has some lead in it, so good ventilation is advisable.
Sandiapaul
Posts: 567
Joined: Wed Jan 07, 2004 8:04 am
Location: Princeton, NJ

Re: USATC S-160 Consolidation

Post by Sandiapaul »

Thanks...and well I hadn't had my coffee yet Harold!
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: USATC S-160 Consolidation

Post by Harold_V »

Sandiapaul wrote: Thu Oct 22, 2020 7:28 pm Thanks...and well I hadn't had my coffee yet Harold!
Chuckle!
Trust me, I understand. I make more than my share of errors like that. We're all human and prone to doing so.
No offense intended, I hope you know. :wink:

H
Wise people talk because they have something to say. Fools talk because they have to say something.
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

Today's casting with no work other than to clean off the investment.

I redid the drawing and print so the walls were thinner than the bell I posted a few weeks ago in another thread. Because of the size it tinkles, but the ring lasts longer. This is one of the best quality castings I've done to date but the photos are disappointing. Except for roughness on the stem, the flaws that show so well in the photo are almost imperceptible visually or to the touch and should polish out easily.

I'm wondering if the improved surface finish and lack of scale compared to the photos from a couple of days age are due to the alloy? This was cast in bell metal, 20% tin and 80% copper. I also decrease the maximum burn out temperature. That shouldn't affect the scale but might prevent some deterioration of the mold surface.
Attachments
20201023_215014.jpg
20201023_215028.jpg
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: USATC S-160 Consolidation

Post by Harold_V »

Very nice, Dick.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

I've been modeling some parts in 3D and printing them in a castable resin for a while and finally did some more casting this week. These are the successful ones. Because of my small casting equipment it can be pretty tedious. I can only burn out a couple of flasks at a time and there is a 12-hour burnout cycle for the flasks.

The valves spools were cast in silicon bronze and the other parts in C9370 leaded bearing bronze. The guys doing the machine work on ARR 557's bearings and shoes were nice enough to carefully collect the chips. The price is right, but there is a lot of loss to dross when they are melted down.

The brake shoes will have a friction material lining epoxied onto them. They will only need to have the braking surface machined and the hole drilled.

The bracket at the top holds a support that goes across the frame for the valve gear.

Below that are brackets that bolt onto the outside of an early Central Pacific tender frame to support the deck and a handle for a blow down valve for a CP-173 copied from the Disney Engine that Jack is working on.

I was curious if I could cast a piston valve spool in one piece. The prototype had cast ends with a piece of tubing welded between them. These came out reasonably well. They are hollow all the way through (except for the sprue which will be removed when I machine them. The one on the left will need some work with a die grinder between the fins where the investment broke away. They are 4" long and 1-1/2" diameter. If I do them again I'll cast the ends separately and silver solder a piece of tubing between them. That will make for a much easier casting but add the need for the silver soldering.
Attachments
20210207_224520 reduced.jpg
20210207_224801reduced.jpg
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

About a week ago I posted a photo of the prototype for a replica Nathan #1 U-joint and valve handle that I had cast and machined from the original Nathan drawings. The full sized Alaska Railroad #557 was short a few due to the need for more valves on the turret to support additional appliances. I've refined it slightly and made up three more. Hopefully that's all that are going to be needed.

Since I had already invested the time in making the 3d digital models, I was curious if I could reduce them in size. The photos are the results of that effort. The little castings are identical to the full-sized ones and use the same digital model, but reduced to 25% of the bigger one using the 3D printer slicing software. The handle is 3/4" diameter and the U-joint is 3/4" long. Bolts are 1-72. The shafts are some #1 screw size brass rod from J.I. Morris Miniature Fasteners that I bought from Steamfitters during their going out of business sale about 35 years ago. I knew it would come in handy some day!

All the holes were included in the casting and only required opening up about .005" to clear the bolt 1-72 bolts. I was surprised that the investment didn't crack in that area and give me inclusions in the castings instead of a through hole. The squares for the valve stem are as cast but I still need to make up a little broach to clean them up. The camera in my phone isn't good enough to pick it up, but under a magnifying glass "Engine 557 #1" is legible. Not bad since the letters are only .012" and .019" high.

I continue to be awed by what a $300 consumer grade MLSA 3D printer is capable of when coupled with basic investment casting equipment.
Attachments
20210529_230909.jpg
20210529_234329.jpg
Last edited by Dick_Morris on Tue Aug 03, 2021 9:51 pm, edited 1 time in total.
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: USATC S-160 Consolidation

Post by Harold_V »

Outstanding! You appear to have mastered investment casting, Dick. Very well done.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: USATC S-160 Consolidation

Post by Dick_Morris »

Harold, Thanks. At least I'm starting to get consistent results and when something goes amuck (as it often does) I generally know what I did wrong.

I just noticed in Jack's 3/4" Scale J1e thread that he was able to fit castellated nuts onto some 1-72 bolts. I was just going to use a touch of Loctite. Back to the shop!
Post Reply