Gallery, Projects and General > Project Logs
Another Halo
bogstandard:
Kirk,
I wasn't :poke: you specifically, it was just a comment about what is happening with the Paddleducks engines.
It is my fault really, for doing a difficult piece at the very end. But that is the only way it could be done, to accurately make it physically fit the engine.
Bogs
ozzie46:
--- Quote from: bogstandard on October 17, 2009, 12:14:44 PM ---Darren,
I have yet to see on any of the Paddleducks engine builds, one with the steam control valve fitted and working.
John
--- End quote ---
Ok John, here it is.
I didn't find the control valve all that difficult to build. :dremel: Just a little bit time consuming to get the spool to length , took me about half an hour. Then again maybe I got lucky. :D
Sorry about the quality of the video. I'm still not to versed on them yet.
Ron
bogstandard:
Absolutely wonderful Ron, you have just made my day.
Many thanks for showing it to us.
Another first.
John
kvom:
Yesterday and today I worked on the most challenging part thus far, the master rod. Because of the irregular shape I figured I needed a jig to hold it. First I reduced a small piece of 1/4" brass to .375" wide by 1.25" long and drilled the holes needed for the wrist and crank pins. After reaming the crank pin hole, I machined it to 1/16" thickness.
For the jig, I found a 3" diameter disc of aluminum about 3/4" thick. I turned one side for a 1" diameter spigot that would mount on the rotab, and then turned the other side with a small .125" spigot that would be a tight fit for the crank pin hole. Once mounted on the rotab and centered under the spindle, I set the rotab to 0 degrees and drilled a .063" hole .850" from the center. I then could mount the workpiece on the center spigot and hold it laterally with a piece of 1/16" drill rod. I then drilled the 4 holes to which the other connecting rods will be pinned:
Next using a 1/8" endmill I tried to carefully machine the profile using a combination of linear and rotary motions. Unfortunately it seems I had a slight undercut on one side.
I trimmed the tail to length leaving a workable, although less than perfect, master rod.
Some lessons I learned. I had intended to drill and tap a hole in the tail as a hold-down (for that reason it was left long). When I first mounted it on the jig it was very solid, so I neglected that step. On a do-over I would do so as the piece did have a tendancy to lift when milling the tail portion. Rather than the spigot in the center of the jig, I would just drill a hole and insert some 1/8" drill rod.
If, like John, I needed to make multiples, I would sandwich all of the pieces and drill/mill all at the same time. I think using a larger endmill and calculating the toolpath for a single cut of the entire profile would be better than the incremental milling I used. I'll be interested in seeing how John approaches this part. I don't really see the need to shape the head as the plan shows unles I find some binding with the rod ends once assembled.
bogstandard:
Kirk,
I will only be able to make two the same, all the rest will be different.
John
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