Silver Bullet in progress

[Groomengineering]

Looking good Mosey! Thm:

Cheers

Jeff

 

[steamer]

Well, I finally am back to work on the Sllver Bullet.
I am working on the fan, which has been duly reported on another topic. Here are some pics of my first attempt to mill a 9 blader. Critiques and comments are welcome. This is how rank amateurs do it.
I am using the universal table tilted to 30 degress, Sherline RT, and 2 mini-clamps. I think I need the elves to come in as this is tiny stuff. I had to align the center of the RT with the center of the mill spindle at the height of the top of the work piece. I have to move the clamps as I rotate the table to clear them.

Hey Mosey,
Something to consider in the future. How about doing the rotarty table job like this. Mount a sacraficial aluminum plate to the top of the RT. In this plate turn or mill concentric grooves over the whole face. Once done face it off clean. Now, super glue your work piece to the plate. NO clamps

To take it off, take the plate off and take it out side and gently wave a torch at it until you can wring the part off with a rag. It will clean up with Acetone once it's cool.

Or you can go old school, and mount the part with Shellac....I'll let Tonybird tell us about that.

Buy the way...+1 for doing the jfan blade job like George describes

Dave

 

[gbritnell]

Hi Mosey,
Very nice job on the fan. On all of my water cooled engines the specifications are different, bore size, number of cylinders, radiator size, shrouded fan, non shrouded, so I don't have a good set of specs to work to. I do know that these little things get hotter than one would think and it takes a combination of all the elements to keep them somewhat cool.
gbritnell

 

[Mosey]

The nice thing about this forum, is that when a person like me with limited expertise produces something obviously not perfect, he gets cheers for trying (see below), and encouragement to keep at it. Thanks.
The fan was a challenge, in that it kept moving on the table until I discovered that I should mill out the spaces between he blades first, and then go back to milling the deep gullets down to the hub. I finally ditched the cover plate, not needed. With 9 blades, the neck where the blades connect to the hub are a little too narrow, weakening the blades. I may try again with a few less blades, but it looks great with 9. Perhaps Stainless would be better, even though it is a bitch to machine in such thin sheet.
I am still not satisfied with the die I made for forming the curved blades, as it allows the blades to shift when in the press, ending up not symmetrical. I'll come back to that later. I also think that the conical form that I press into the blades has to be mounted on a hinge-pin so it meets the blades exactly on their central axis. By the time I'm done, I guess I could make a real-scale engine. Next will be the radiator from the Bob Shores kit.
Nice suggestion below about the gluing it down to a sacrificial plate.
By the way, if I get lots of heat, I will be in heaven, because that means it is running.