Author Topic: The Dickson!  (Read 15200 times)

Offline b.lindsey

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Re: The Dickson!
« Reply #60 on: April 03, 2018, 01:07:19 AM »
Wow, very nice looking crankshaft maury!! All these details are going to make a fine looking model for sure

Bill

Offline maury

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Re: The Dickson!
« Reply #61 on: April 04, 2018, 02:50:18 PM »
Guys, thanks for all the nice comments!

I guess I was in a bit of a hurry when I posted last.
As I said I used the spin index to get the proper rotation of the cranks. So What I did was to position the first throw on the shaft using Locktite262. After hardening, I drilled and reamed the pin holes for .125 pins. Then rotated the spin index 120 deg. and repeated the process for the other 2 throws.

The reason the pins don't show on the final pic is because they are covered by the counterweights. I thought it more attractive to hide them.

The materials I used were:
Drill Rod for the shaft parts, I like it because it's ground to a nice finish and it's harder than the usual softer steels.
I had some 1144 in my bin, this is my favorite steel to use for most general applications because of the finish I get and the nice way it machines. Also, machined this dry. Almost like cast iron but without the mess. I used it for the counterweights
The throws were made from 1018 because I had some of the size I needed. I will use 1018, but it's gummy and doesn't give a great finish with using oil. Thus a mess.

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

Offline gbritnell

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Re: The Dickson!
« Reply #62 on: April 04, 2018, 07:25:01 PM »
HI Maury,
Great work as usual! I really like the crankshaft.
gbritnell
Talent unshared is talent wasted.

Offline maury

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Re: The Dickson!
« Reply #63 on: April 05, 2018, 05:11:13 PM »
George, Thanks! I appreciate the compliment
maury
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Offline maury

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Re: The Dickson!
« Reply #64 on: April 09, 2018, 10:07:59 PM »
Hi Folks, I cut the pattern for the drag side of the Low Pressure cylinder today. Dennis is designing these parts and sending me .step files so I can run them on my CNC. This was a 3D run, and was about 8 hours. It is made from REN, a really nice material for making foundry patterns. I used a 3/8 tool for roughing, 1/8 for rest roughing, and a 3/16 ball end mill for finish.

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

Offline J.L.

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Re: The Dickson!
« Reply #65 on: April 10, 2018, 01:07:05 AM »
HI Maury,
Absolutely stunning work.
John

Offline Dennis

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Re: The Dickson!
« Reply #66 on: April 22, 2018, 10:26:19 PM »
Hello everyone,

Finished up the patterns and core boxes for the 6 columns for the Dickson model last week and got them to the foundry.  Here is a photo of the pattern for the three front side columns and their core boxes.  These are simple "strike off" core boxes cut on my CNC router.  The pattern pieces were also cut on my CNC router.  I will post photos of the parts when they are cast but not sure when that will be.  The foundry looked busy and I didn't ask the lead time, just grateful they will still cast my small volume parts.

The High pressure and intermediate pressure cylinder patterns are being assembled in the shop now.  Maury machined the pattern pieces from REN board and it is really nice to work with.  First time for me with the REN board, wish I could afford to use it more but it is quite expensive.  The core boxes for the cylinders and steam passages are much more complicated than the column core boxes.  The cylinder core boxes are made in two parts and they will be closed with several vents on one side and multiple high pressure fill tubes on the other side.  Not sure what this process is called but it makes a very dense and strong core.  The foundry guys taught me about this process when I was having trouble making cores that would hold together for the compound condensing marine engine river gypsy built.  I will post some cylinder pattern and core box photos when one of them is finished. 

Dennis

Offline 10KPete

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Re: The Dickson!
« Reply #67 on: April 23, 2018, 02:36:27 AM »
Sodium silicate or CO2 cores.  Wonderful invention.....

Pete
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Offline maury

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Re: The Dickson!
« Reply #68 on: April 23, 2018, 06:57:35 PM »
Dennis, great looking core box.

10K, you can't use sodium silicate on iron, it will fuse like glass and you will never get it out. Actually, it might even melt and deform. I believe the foundry is using either baked cores or Air set sand.

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

Offline 10KPete

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Re: The Dickson!
« Reply #69 on: April 23, 2018, 07:13:36 PM »
Dennis, great looking core box.

10K, you can't use sodium silicate on iron, it will fuse like glass and you will never get it out. Actually, it might even melt and deform. I believe the foundry is using either baked cores or Air set sand.

maury

Maury, the silicate is not used alone in making a CO2 core. There are other additives/factors which are used/accounted for in using this system, which was invented/patented around 1959. Silicate cores have been used for iron since day one.

Here is some basic information on the system:

http://www.hillandgriffith.com/green-sand-metalcasting-foundry-news/sodium-silicate-binders

https://www.budgetcastingsupply.com/product-p/1025-qt.htm

https://patents.google.com/patent/US2883723

I hope this helps,

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Dennis

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Re: The Dickson!
« Reply #70 on: April 23, 2018, 10:01:11 PM »
Pete,

Thank you for the additional information.  I will make good use of it.  My pattern making and foundry experience is from trial and error so every little bit helps.  I make something and when it doesn't work the guys at the foundry are kind enough to explain why.  Wonderful people and I have been working with them for 20 years now.

Dennis

Offline maury

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Re: The Dickson!
« Reply #71 on: April 26, 2018, 08:52:20 PM »
Guys, Thanks for all the nice comments. I decided to jump in on the main castings for the Dickson.
The base Plate seems like a good place to start.

1) the casting was a bit rough, so I did some initial fettling to get it where I could get a good
setup for the first cut. This is important because everything will be referenced to it.


2)Bearing Mount Holes: After the first cut, the casting was fettled some more to get a good top side
setup.This setup was maintained for the remainder of the machining of the part. The column pads and
main bearing cap pads were machined to finish height. Then the stud holes for the mains were drilled.

3) Base Mount Holes: The base mounting holes were located and drilled. There were small discrepencies
between the Dims and the locations of the pads on the casting.So I centered the holes on the pads and
recorded the dims on the drawing for future use on the foundation casting.

4) Mains: Since the stud Holes intersect the trough for the mains, they were done first. Then the
trough was cut to Dim.

5) Columns: Notice the hankypanky with the clamps. They were moved one at a time to preserve the setup.
Had to do this twice. I did sanity check the setup with the DRO before proceeding each time.The 48 column mounting holes were drilled and tapped. a bit tedious.

6) the machined bed plate.


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

Offline crueby

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Re: The Dickson!
« Reply #72 on: April 26, 2018, 09:12:27 PM »
Great job on the base, thats a lot of holes to get lined up.   :ThumbsUp:

Offline maury

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Re: The Dickson!
« Reply #73 on: April 27, 2018, 04:28:41 PM »
Crueby, thanks for the compliment.
If it weren't for my DRO I would never have been able to Get all those holes right. Thanks for technology.
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline Dennis

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Re: The Dickson!
« Reply #74 on: June 03, 2018, 07:55:29 PM »
Hi everyone,

Last Friday, I picked up the cast columns, bearing caps and cylinder heads for the Dickson engine model.  Did some trimming on the castings and the first set of parts (in the photo) will ship to Maury Monday morning.  Still with a lot of trimming to do.

In the photo, the in-gate for the columns is at the top of the column.  I left most of the gate on the parts in case we wanted to use it to clamp the columns down for machining.  The workers at the foundry cutting off the gating can get a little heavy with their grinders and saws so I always tell them to trim the gates at least a half inch from the part.

The cylinder heads all have a large chucking post on the back side which makes them easier to hold for machining.  I left the bearing caps attached to a strip of runner so they wouldn't get lost so easy.

The three cylinder patterns and core boxes are being worked on now.  They are nearly finished so at least one of them should be at the foundry late next week to see how the pattern and core box are going to work.  We want to be sure the cores in the steam chest area and steam passages will be strong enough before running all of the patterns. 

Dennis