The Dickson!

[maury]

Kim. thanks for the compliment.

So, now I have completed 1 of each of the 3 sizes of gate valves.

Pics below.

maury

[b.lindsey]

Those look great! Maury. Sorry the investment process didn't work but the sand cast bodied look the part for sure and then handwheels are beautiful with the CNC work.

Bill

[maury]

Thanks for the compliment Lindsey, it's appreciated.

Working on some of the piping castings, I started with a simple one. The 10" scale extension pipe. It has 2 identical flanges, Drilled for 1-72 screws. The pics:

1) the casting
2) Facing the first flange in the lathe
3) Drilling the passage hole
4) cutoff finishes the lathe work
5) A setup is needed to make sure the flanges are centered on the casting and they line up end to end.
6) Using the DRO I first center drilled the BC, then drilled the 1-72 clear holes. Don't have another pict, but I flipped the
part, aligned with the lower BC, then drilled the upper BC.

maury

[maury]

Making the pipe_8_8_8_8 was a little more challenging. there are 4 flanges, all the scaled 8" size, but must
be in alignment on the through passage. The other 2 flanges must be perpendicular to the through flanges , and
have different ofsets. The fully assembled piping structure is bolted to all 3 cylinders, and is hard, as in
no adjustment to the structure. it is critical that each piece is spot on dimension.

Additionally, the part includes a difficult coring challenge. I avoided that by making a 2 piece casting set,
requiring the machining of the passage way and subsequently soldering the parts together. This has actually
worked out quite well. Other parts in the piping part of the Dickson project also use this method.

After the part is soldered together, it may be machined as a regular casting.

1) cutting the passage uses a 1/4" ball endmill, and is cut to a depth of .125. This of course gives a 1/4"
Dia passage. Note, the passage is not milled to an accuracy that will allow using it for a reference to later
operations. The OD of the flanges is carefully measured and used, the BCs on these flanges will be centered
on this OD measurement.

2) The halves soldered together. Note, the parts were sanded with rough sandpaper on a flat surface before
 the passages were cut. The castings were good, and it was not difficult getting a flat clean surface.

3) First OP: I didn't show a setup pict. but the part is setup in the vise with the tops of the 2 pass through
flanges parallel to the X axis of the mill. Measurements in the Z are setup on the Z DRO, and the flanges are cut.

4) The Bolt Circles are drilled

5) Second OP: The vise holding the part is then rotated in the Mill vise, exposing the next flange to be cut,
and keeping everything square. Next the vise is rotated again exposing the final flange.

Hope this gave some ideas for those challenging casting setups.

maury

[maury]

Hi Folks, well there has been a lot of plug & chug here. The piping sub assemblies are coming together. I need more castings to finish the valves and my knee is out of commission, so it may be a few weeks. I still have the governor and a couple  more pipe fittings to build, will keep me busy for a while.

I'll be glad to get to the next phase of the project, there are lots of bolt patterns to make on these parts, and over 200 tapped holes. Almost all are 1-72. Still having fun.

1) Pics 1,2,3 are the High Pressure Cyl to Intermediate Pressure cyl  piping connections.
2) Pics 4,5,6 are the Intermediate pressure to Low Pressure cyl piping connections.
3) Pics 7,8 are the Exhaust piping connection from the Low pressure cyl.

maury

[maury]

OK Folks, a little shift away from working on the piping. I have the drawings from Dennis for the base parts of the Dickson, so I thought I'd start on the crank shaft. I need to fettle the castings before I start on them. I made models of the crank parts in Solidworks, Also changed the design a little I won't be exactly scale because of this, but I wanted to make the crankshaft shaft with a single piece of drill rod. The original engine design has the crank shaft built in 3 pieces and bolted together with flanges. My experience tells me I won't be able to make that design accurate enough without the crank binding a bit.

I had a couple of busy days in the shop with 4 machines running. Had a great time. Here's what I've made so far.

1) I ran the model for the crank bell on the CNC. (actually did this 6 times). I chose to use round stock.  So to prepare the stock I faced  both ends of a piece in the lathe to get a parallel surface with a good finish for the face. I ran the part in the CNC, then used the band saw to cut it off a bit proud of the needed Dim.

2) I also made a Solidworks model for a tool to face off the other face. The pattern is a few thou bigger than the bell, and uses 2 set screws to hold the part in while facing. The bells were faced to Dim.

3) The 6 crank bells then needed the holes reamed because my CNC has a bit of backlash and the holes are not only not exactly round they are not quite the right size. Fortunately, they are smaller than Dim. I want a medium press fit with the shaft. After assembly, the bells will be pinned to the shaft.

Next time the counterweights, They should be even more fun.

maury

[maury]

Well Folks, another fun day in the shop. Today I worked on the Crankshaft counterweights. I had to diddle with the geometry a bit to get a nice tight fit between the bell and the counterweight to compensate for the backlash in the CNC. Hit it on the first try. I was able to cut two parts before my tool showed too much wear to go on. it is an old 3 flute carbide tool, and it has made a lot of steel parts. ( Chuck: if you are tuned in could you send me the contact info for the tool place in Round Rock please? )

I used a 3D tool path to avoid making any heavy cuts, balanced with cutting air. The part is about a 1 1/2 hour run.

1&2) CNC cutting the part.

3) The counterweight after being cut off in the band saw and facing the back face in the lathe.

4)The counterweight and bell assembled. I was planning to use set screws to hold the parts together, but  they fit tight enough that I may use LockTite.

maury

[Dave Otto]

Nice looking parts Maury!


Dave

[maury]

Dave, thanks for the compliment.

Also looking forward to seeing more of your excellent work. Max tells me the Pacific is getting lonely.

maury

[Dave Otto]

The Pacific is lonely, I havent been able to work on it since I made the pulley back in November. Part being busy with other projects and part procrastination.
Max walked by it the other day and mumbled something about that thing needs some paint.
Hopefully I will get back to it soon.

Dave

[maury]

Moving along on the crank shaft, I am assembling the 3 throws as sub-assemblies before
assembling the whole crankshaft.

1) The Throw parts. The new part is the little shaft made from drill rod. It has a tight
press fit into the crank bells.

2) The Throw tool holds the shaft vertically while pressing. I use a manual press, one of the
cheap ones, and while pressing it seems to like skewing the components off vertical. The tool
helps that.

3) Ready to press.

4) After pressing one crank bell to the shaft, the second one is aligned with piece of drill rod.
The fit is a light press.

5) the finished crank throw.

maury

[Admiral_dk]

Interesting jig for assembling the throws 
I'm guessing that you will make another to assemble the complete crank .... will it also have features that ensures that the throw angles are correct or 

[maury]

Admiral, thanks for the question. Actually, I was going to make a 60 deg. jig to hold the frank
 for drilling the holes for pinning the throws to the crank, but the light turned on. I ended up
using the spin index. Worked out well. I'm including pics for the setup of each throw, and some
shots of the finished crank.

maury.

[Admiral_dk]

So if I understand the pictures correctly - you pinned / screwed the throws onto the shaft - though I do not see the evidence on the last pictures 

Thanks and best wishes

Per

[Dennis]

That is a nice looking Crank shaft Maury.  I really like the way you put the parts together and the idea for setting the rotation angle on the individual cranks.  Did you use the 308 stainless for the crank parts? 

Dennis