Casting Pelton turbine spoons in aluminum

We had 7th grade wood shop for a semester. Drafting in 7th or 8th grade - I don’t recall which. Possibly it was one semester or drafting and one semester of woods the same year.

Freshman metals was essentially a joke. Some tin knocking which I was WAY beyond so was put in with the junior and seniors metals - which I was also too advanced for.

My home school had a small speedy melt foundry furnace that they never used. Dad ended up donating all the supplies they needed from his program yet they scrapped the foundry in the late 80’s. I found the furnace at the scrap yard and brought it home. It sits on the shelf. I’ve not seen a flame in it since 1978. We did have a forging furnace and some Lincoln dial arc welders.

As you so well understand - how is a student to know if they want to take a vocational level class if they have zero exposure?

My dad’s program was at a vocational center. So - as you can figure for yourself - with zero or very poor home school exposure why would a student take a class that consumes 3 to 4 class periods?

Morning class requires arriving to school via their own transportation as they need to take a special bus to arrive to the career center early enough for an approximately 2 hour class and then get bussed back to their home school. The afternoon class takes the place of 4 class hours. That is an absolutely daunting commitment for a student who may have absolutely zero prior exposure.

School counsellors fail the metal working students by not preparing them for a trade that requires a sound understanding of math. It is less of an issue with on-line help but a machinist still needs some background.

My son took a school auto shop program a decade ago that utilized Lansing Community College. It was a joke. They were not teaching an auto mechanic class. It was intended to create “technicians” who were to attempt to tell a mechanic what was wrong with the car - but not perform actual repairs. He wasted a lot of class time for 2 years.

Another class he took at his home school was “manufacturing”. It was claimed to help prepare for manufacturing jobs and business experience. All they did was operate a Woodmiser band mill making lumber that the wood shop instructor sold to help fund his wood shop program.

That same instructor sold off the shear, sheet metal brake, slip roll, corner notcher, bar folder, the 1950’s Clausing lathes, the Emco training CNC mills, and a small CNC lathe. He sold the entire foundry for under $200. He sold/traded a fully automatic surface grinder that had been donated by Post Cereals in Battle Creek. It was still brand new and on it’s pallet when the prior shop teacher showed it to me 2 years before. He wouldn’t say what became of it. He bought a couple Jet lathes. One broke after a year. It was used for parts to keep the other working for a few years. Both were not usable within 5 years due to broken plastic gears and sold for scrap when 7 or 8 years old. He also bought a small Lincoln MIG welder. He told me he wanted to buy a CNC controlled plasma cutter. I asked why? You sold off the sheet metal tooling needed to work with any parts the student would cut with the plasma cutter. He had no answer.

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I finished casting the spoons and cleaning them up. I then weighed them, matched them up in pairs which were closest in weight, and then adjusted the heavier one down to match its mate.

I am using parts of an old burned out water pump to make the runner and bearing assembly. The pump rotor makes an excellent disk to which to attach the spoons. It is balanced and has a key on the shaft. The shaft itself is long, which means it can hold the disk far from the old motor face and well into the turbine housing. I removed the field coils and stator iron making the assembly light weight.

The one thing I wish I did better is welding the screw thread on the end of the shaft better. The bolt wobbles, but it doesn’t really affect anything.

I attached the runner to the shaft and spun it up to 6000 rpm. This is 3 times faster than operational speed and 1.5 times faster than runaway unloaded speed for the runner. I was amazed that it was well balanced and needed no fine tuning. And I was all set to show you all the balancing app on my phone. :cry:

The next step is to construct a turbine housing at the site and install the turbine.

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Actually there are 5 axis 3d printers. on the market today. You PROBABLY could rewire it with a newer driver board and touchscreen. I got the monster8 v2 driver board. that I am rewiring my 3d printer with but it has slots for 8 separate mosfets. With a very brief glance, it appears as though Marlin firmware supports 5-axis.

However, 5 axis gantry kind of screams a 5 axis cnc mill or router to me, and there is potential to run a 5 axis with the open source grbl software. It is on my ‘wish list’.

This is the board I have, which i got because it also looked good for a cnc router type of project as well, except I am not sure if it has software support for it.

It sounds a lot like what happened at our high school. They have a cnc plasma table, but they sold off the old equipment for cheap when they killed off the shop programs. Like all the teachers retired within a few years of each other and they just shut down the programs. We had one substitute teacher that was trying to start up an electronics program for robotic stuff late 80s with cnc, but that didn’t make it through.

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The BPM Personal 3D modeler was unlike anything I’ve known. NASA actually tested one in space for producing patterns / components in a weightless environment.

It used an ultrasonic inkjet printer nozzle to ultrasonically propel the build material during the build. The microscopic particles of build material were able to build in overhang situations - often without supports. Surface finish was fine satin - nearly gloss. Generally no lines or layers would be evident. Standard accuracy in the 0.003inch range. It was capable of better accuracy with repeated alignment procedures. The software had a built in nozzle alignment feature where the operator would observe a series of printed lines and determine which was the most accurately placed. Enter the most accurate line numbers. Clean the build platen and repeat. Each time this was done, the software adjusted the print scale to improve resolution for the next alignment test. This is still commonly used for ink printers. I was told the print heads were made by Hewlett Packard but was not able to obtain replacements from them.

The software used industry standard STL files. These could be written and imported into the machine. At the time I was told Pro-Engineer seemed to produce the best files. The machine software produced a hollow honeycomb within the outer surfaces to reduce the amount of build material used. Unfortunately the build material was a proprietary styrene and wax product which was rather brittle. Persons not familiar with the delicate nature of the components would often leave “finger print” impressions where they crushed the outer shells.

I was put into contact with a gent in Georgia who used one to make architectural building models. There was a listing on ebay about 15 years ago by someone who had worked with converting BPM modelers to use bismuth metal for the build material. They had obviously spent quite a bit of time working with the modeler, added air-conditioning for internal temperature controls and had built some parts from bismuth. They had a number of spare parts being sold with the units. I also had talked repeatedly with the factory service tech from BPM and the last time we talked I was offered the ability to obtain all remaining inventory of parts he had in his garage. Price was great. He wanted the space in his garage. I chose to not proceed and contacted the gent in Georgia so that he could obtain them.

The fire at the business and what has occurred in the subsequent years has changed my plans. I need to do what I and my dad were not good at doing - getting rid of projects and simplify my life.

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Here is a gal that joined a Yahoo rapid prototyping/ 3D printing group I was on some 20 years ago. She uses 3D printing for patterns. Bathsheba Sculpture - Jewelry

I had described to more than one shop teacher how they could bring art students into the shop as foundry students using soft wax as a pattern medium. I liked modeling using the red sealing wax used on import cheese. Warming in your hands made it soft and pliable.

Slurry can be used for coating the investment pattern. Buildup of each layer of slurry is commonly accelerated using a crystalline material such as sand, ceramic beads, or other heat resistant media. Possibly even glass microballoons used in composite resin work. I’m even thinking milled glass might be able to be added to some slurry or dusted over the fresh wet slurry coating to improve strength of the mold.

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