Author Topic: The Dickson!  (Read 10999 times)

Offline Dennis

  • Full Member
  • ****
  • Posts: 29
Re: The Dickson!
« Reply #30 on: August 31, 2017, 06:04:27 PM »
Glad you area safe Maury.

The piping patterns look great, The cnc is really great for patterns like this.   A nice approach to making small complicated piping. 

Dennis

Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #31 on: October 05, 2017, 07:51:23 PM »
Well, folks, it's been a while, s o I thought I'd post a bit of an update.
Since I have been working on the valves and piping it has become evident
that some of the parts would not work with sand casting, leaving 2
alternatives. Investment casting seemed the only acceptable choice, so
I set about seeing how I could make that happen. Idid some reading and
talking with folks and also foundry. Well it came down to me having to set
up here at home.  I bought a burn out oven, but the accessories were harder
to come by. I ended up making the racks and tongs. I couldn't find the
proper size wax tray, and I don't have a finger break, so I had to settle
for a smaller one than I wanted. Here are some pics of the back end
equipment I have. On a later post I'll show making the molds, the waxes, and
the trees.

maury

"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #32 on: November 19, 2017, 03:23:57 PM »
Well folks, it's been a while, so I thought I'd give an update. The project is not dead.  It's cooling off a bit, so I am able to do a bit of foundry work. Unfortunately, I've been less successful on this project than some in the past. I seem to have trouble getting my sand molds to fill properly, and so far my investment casting has been a disaster.

Included are a couple of pics of castings. The piping and valve tops are done in sand, There has been some issues with filling, so I spread the parts between 3 patterns instead of 2, and improved the gating. Will be casting these new patterns before too long.

The second pic shows the 3 sizes of gate valves, the valve body being cast in investment. I have a few parts, none of which are really nice, but good enough to machine and verify the design. None of the valve handwheels have turned out so far.

Kind of a bummer, but making progress and learning a lot.
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline fumopuc

  • Full Member
  • ****
  • Posts: 2196
  • Munich, Germany, EU
Re: The Dickson!
« Reply #33 on: November 19, 2017, 04:26:59 PM »
Hi Maury, I am following along with big interest.
Kind Regards
Achim

Offline Dave Otto

  • Full Member
  • *****
  • Posts: 3373
  • Boise, Idaho USA
    • Photo Bucket
Re: The Dickson!
« Reply #34 on: November 19, 2017, 04:36:08 PM »
Hi Maury

Looks like good progress, are the patterns for the investment wax or some other material?

Dave

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6020
  • Surrey, UK
Re: The Dickson!
« Reply #35 on: November 19, 2017, 05:09:31 PM »
They look a lot better than quite a few castings we are expected to pay for!

Interested to see how you machine the U shape for the gate to slide in

Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #36 on: February 28, 2018, 04:35:42 PM »
Well, contrary to what it may seem, the Dickson is NOT dead.It's been a while, but what happened was I wasted a lot
of time and and investment trying to investment cast the valve bodies and handwheels. Sorry to say it was a complete
failure so I decided not to wast any more time on investment casting and redisigned the valve bodies for sand casting
and fabrication of the flanges.Also the handwheels are now being done on the CNC.

There are 3 sizes of scaled gate valves, and the engine needs a total of 9 valves. I have goof patterns that I have made
castings from, and have started machining them.
I'm including pictures of ine of them through the process.
1) the casting
2) Cutting the pass through to Dim.
3) I didn't show making the flanges from bar stock I cat, but here they are being soldered to the body.
4)Cutting the Flanges thickness to Dim.
5) Drilling the pass through.
6) Drilling and tapping the bolt circle on the Flange.The setup allows the other side to be done after centering.
7) Setup for the valve body top and cutting to dim.
8) Cutting the slot for the gate.

The bolt pattern is then drilled and tapped on the the top. Boring picture, but it really helps a lot
to have a DRO. If you don't have one you need to get one.

More on the valves later.
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline Mcgyver

  • Full Member
  • ****
  • Posts: 139
  • Toronto
Re: The Dickson!
« Reply #37 on: February 28, 2018, 05:59:18 PM »
Hi Maury,

can you explain a bit more whey the investment casting didn't work and what you think went wrong?  The stuff in post 32 looks great?  Investment casting is something I look forward to trying so am curious what happened

Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #38 on: February 28, 2018, 08:39:49 PM »
Mcgyver,thanks for asking. The bottom line is I just could not get my molds to fill. Those 3 valve body castings you see in post 32 were 3 of 4 out that molded ok out of at least 50 to 75 that I poured. I'll post a pict of the handwheel  later. I did everything by the book, that is the jewelry casting book suggested by another member on this board. I vaccuumed the investment before and after pouring into the mold, I used recommended  burn out times, poured the metal at the right temperature into the molds which were at the correct temperature, and on my final try, I even vented the waxes thinking there might be too much air getting into the mold. All no go.

Hope this helps,
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline Dan Rowe

  • Full Member
  • ****
  • Posts: 723
  • Dripping Springs TX USA
Re: The Dickson!
« Reply #39 on: February 28, 2018, 08:50:27 PM »
Maury, were you using a solid flask on a vacuum table when you made the pour? I use 1/8" sprues for all but the smallest parts and the vacuum is needed to draw the metal into the mold.

Come down to my shop or I can visit you if you want to see my process.

Dan
ShaylocoDan

Offline Mcgyver

  • Full Member
  • ****
  • Posts: 139
  • Toronto
Re: The Dickson!
« Reply #40 on: February 28, 2018, 09:42:55 PM »
Maury,
thanks for explaining more, I feel the frustration.  If nothing else I won't feel so lonesome if I have trouble.   I'm inexperienced but have been collecting the equipment and reading up on it.  The one thing you said that struck me was vacuuming before and after; I thought you vacuumed during the pour to pull the metal in as Dan notes?



Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #41 on: February 28, 2018, 09:53:31 PM »
Dan, thanks for the offer. I would like to hook up with you next time you do a pour. I can PM you my phone number, and I'll need a GPS address for you.

I don't have a method for pouring the metal under a vaccuum. This may be what my problem is. So, I thought the investment was porus enough to allow gravity to get the metal into the mold cavity. I am using 4" solid flasks, 4" high.


McGyver, I was using the vaccuum to get the bubbles out of the investment while making the mold. Not while I was pouring the mold.

maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline Dan Rowe

  • Full Member
  • ****
  • Posts: 723
  • Dripping Springs TX USA
Re: The Dickson!
« Reply #42 on: February 28, 2018, 09:56:09 PM »
The investment is mixed then vacuumed before pouring into the flasks. Then it is vacuumed again to remove any bubbles. This needs to be all ready to go as the working time of the investment is 12 to 15 minutes.

I have had trouble getting vacuum a few times before a pour and made the pour anyway... the results are usually disappointing.

We were posting at the same time. I will let you know the next pour I have.

Dan
ShaylocoDan

Offline maury

  • Full Member
  • ****
  • Posts: 409
    • Lone Star Engine Works
Re: The Dickson!
« Reply #43 on: March 04, 2018, 10:15:32 PM »
So here are more parts for the gate valves. It seems the piping and valve work has been about as much as building a whole steam engine from a kit. Been having fun though, and learning a lot: even at my age.

1) This is the part I modeled and wanted to investment cast for the valve handwheels. This the only part which filled as well as it did, and the one of very few that filled more than about 50%

2)These are the Handwheels I made on the CNC. They are a 2 setup job, and take about an hour to cut. Multiple tool changes, and 3D milling The handwheels are about 1" in Dia.

3) The valve stem and the gate. The stem is made of .0925 drill rod with a collar soldered on. The thread going into the stem is left hand.
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Online Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3181
  • Portland, Oregon, USA
Re: The Dickson!
« Reply #44 on: March 05, 2018, 05:28:44 AM »
Wow, Maury, those are beautiful hand wheels!  Well worth the effort.  Sorry the investment casting didn't work out as well as you'd have liked.
Kim