Author Topic: PM Research Dynamo, I know, not unique but it is my first ever casting kit build  (Read 1479 times)

Offline Doug Doty

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Kinda boring for veteran builders I am sure but this is my fist ever casting kit !!  taking up this hobby at 57 yo.

  I just thought I should do this first, kind of an initiation into the hobby project. I have much more ambitious ideas following this but starting small is good. Got this squared up on the mill today, it still needs centerline established and both ends cut to finish o/a length before I do the bore. It is a start and I am going to love this hobby and the projects that gives me reason to utilize my machines. I have had my mill and lathe for many years, they used to support a drag racing hobby and the uses were mostly un precise and even rudimentary in comparison but with a wore out back I can't do that anymore and I think this is going to be a ton of fun. I visited a NAMES show in 2019 and am going to another small show in Ohio on the 25th or 26th this month, I got hooked on the model engines at that NAMES show but have been a slow starter due to other things. Ready to go now !!


Doug...
« Last Edit: September 12, 2021, 04:41:11 AM by Doug Doty »
Just 1 wobbler so far to help pick up my milling skills.

Offline RReid

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Some projects are simple and some are complex, but all are interesting. Looking forward to seeing how you get on. :ThumbsUp:
Regards,
Ron

Offline Don1966

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Great project Doug I built one years ago to go with my Two cylinder Marine steam engine. You will enjoy building it….. :ThumbsUp:


 :cheers:
Don

Offline propforward

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It’s a great choice for a project. That will be great fun!
Stuart

Forging ahead regardless.

Offline steamer

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Have at it Doug!   following along!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Doug Doty

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Thanks for the kind words guys, I had built this little wobbler 3 years ago after watching a Mr. Pete video online and I will see how much power I can get out of the little dynamo with it when I get done. Still deciding on what to build, I would like go to the next show to look before I commit but would really like to do a hit and miss, like a Red Wing, I have had a small collection of hit and miss engines in the past and always like them. There is a fella that done a very detailed build on the water cooled Red Wing online so it could be a great resource for such a large 3rd. project for a newer hobbyist. We will see if anything at this next show changes my mind.


<a href="https://www.youtube.com/watch?v=9A1tPX-e4iw" target="_blank">http://www.youtube.com/watch?v=9A1tPX-e4iw</a>
Just 1 wobbler so far to help pick up my milling skills.

Offline Roger B

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That looks to be a nice project especially as you have a planned use for it  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Online Jo

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Hi Doug, Using a mill to true up what looks similar to a engine cylinder casting  :thinking:  You might be putting a lot of trust in the quality of the casting to be true - they have a habit to be a bit all over the place. This is what makes castings such challenging, but fun  :) , beasties to machine.

The first thing to think about, when we machine a casting, is where the master datum should be to get the best out of the outside shape of the casting. On a cylinder I would use the outer curve of the cylinder rather than the port face. I know that sounds like an odd place to start but its actually easy as you can hold the cylinder in a 3 or 4 jaw chuck on the lathe by the outside of the cylinder and that allows you to skim one end, turn it round, put the casting solid against the chuck, then both face the end and bore at the same time and that end of the cylinder from this point onwards is the master face which faces towards the crankshaft. Yours as it is a generator it requires both faces to be true so I would be tempted to mount it on a mandrel when taking it to length   ;)

If you get a chance it may be worth having a wander through some of the threads to see how other people have machined their casting sets. It is always fascinating and you will find that we use different techniques than are common in commercial work.

Jo
« Last Edit: September 14, 2021, 08:08:24 AM by Jo »
Enjoyment is more important than achievement.

Offline Doug Doty

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Hi Doug, Using a mill to true up what looks similar to a engine cylinder casting  :thinking:  You might be putting a lot of trust in the quality of the casting to be true - they have a habit to be a bit all over the place. This is what makes castings such challenging, but fun  :) , beasties to machine.

The first thing to think about, when we machine a casting, is where the master datum should be to get the best out of the outside shape of the casting. On a cylinder I would use the outer curve of the cylinder rather than the port face. I know that sounds like an odd place to start but its actually easy as you can hold the cylinder in a 3 or 4 jaw chuck on the lathe by the outside of the cylinder and that allows you to skim one end, turn it round, put the casting solid against the chuck, then both face the end and bore at the same time and that end of the cylinder from this point onwards is the master face which faces towards the crankshaft. Yours as it is a generator it requires both faces to be true so I would be tempted to mount it on a mandrel when taking it to length   ;)

If you get a chance it may be worth having a wander through some of the threads to see how other people have machined their casting sets. It is always fascinating and you will find that we use different techniques than are common in commercial work.

Jo

Thanks for your input and I do appreciate it. I do now do see the advantage in doing it that way. !!   Short of that, I started with truing the bottom of the casting as the top side of the 4 corner bolt down flanges seemed the truest and best starting place on this casting. I held it end to end between the jaws packed with some aluminum while probing the four corners get it the most square.  I have gotten lucky this time as the bore is now done as well as the machining on the end bells and the register diameters and they seem to make the most of fitting the main body when I mock it together. In the future I will give your method and look before doing it like this again. In this case the casting is very good and it helped me !!
Just 1 wobbler so far to help pick up my milling skills.

 

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