Rudy's Radial 5 at Half Scale

[b.lindsey]

Aside from some more drawing, I have gotten one fiddly little bit made today...the vent for the crankcase. Made from a small length of 1/16" brass rod...tapped 0-80 on one end, rounded on the other and then drilled and cross drilled with a #73 drill. A few pictures are shown below.

Bill

[Dreeves]

Bill, I checked my crankcase dims. The bolts are on a .390  bolt circle. It's .195 x and y from the center of hole.  Hope this helps.  If it wild help I could sent you a dxf file from autocad 2004

Dave

[b.lindsey]

Thanks for the info. Dave.  That would be half scale to the original dimension of .781"  My problem is that the head size for 0-80 SHCS's takes up more space than the mounting flange allows. The flange allows for .078" and the head size for the 0-80 is between .093-.096".  I may try turning the head down on one and see how it looks or await further info from Marv's source on the 00-90's.

Bill

[Don1966]

Still watching you Bill.     


Don

[Dreeves]

I will check the head size of my 0-80 shcs. I may have undercut the lower part of the cylinder. I will check that as well

Dave

[zeeprogrammer]

Sorry Bill. 3 pages of posts and I never saw it.
Lately it seems I can miss 24 hours of the forum and there's 48 hours of worth of reading to catch up on.
Lot's of projects going on!

I always like to see your work.

 

[b.lindsey]

Thanks Dave.  I also figured out I can reduce the diameter of an 0-80 SHCS to the .078" needed and it doesn't look too bad. I tried it on a round head screw also and it ended up looking more like a fillister head screw which would work too.  I really appreciate the help though!!

Zee...not to worry...the fact that there are more and more projects showing up is a good thing for the forum!! I haven't posted much in the way of a build lately so its nice to be contributing again.

I'll have some more pictures in a little while.

Bill

[b.lindsey]

Here's the last bit for today...I made some progress on the crankcase. Beginning with a length of 1.25" dia. aluminum, I faced both ends, cleaned up the OD and began drilling and boring it to the .813 ID (sorry no pictures of that). After parting it off and facing it to length I attached it to the fixture shown yesterday and mounted the RT vertically on the mill (photo 1) to cut the 5 flats (photo 2). A 1/4" ball end mill was used to make the recesses at the corners (can there be 5 corners??) as shown in photo 3. After re-centering the fixture so the center of each face was right under the mill spindle (photo 4), I drilled each face with a 1/4" drill followed by a 5/16" end mill to finish off the cylinder holes (photos 5 & 6). Then is was on to the rather tedious process of stepping off in both the X and Y directions from the center of the cylinder holes to center drill and then drill the four mounting holes for the cylinders shown in photo 7.

[Don1966]

Cool Bill, that cylinder is looking the part and you can tell it's small by looking at the fixture Allen head cap screw. That crankcase vent must of been fun, man that's small.

 
Don

[b.lindsey]

After getting all that done I could take the crankcase off of the fixture, do a little deburring and make a trial fit with the bearing housing. Just a few more photos at this stage below. This little thing is smaller that I had imagined which photo 2 shows. The crankcase still needs the 5 holes on both the front and back faces drilled and then ALL 30 of the holes have to be tapped 0-80. At least they are all through holes rather than blind ones.

Thanks for checking in.


Bill

[b.lindsey]

Thanks Don...I think the second picture above with the quarter shows the size best. And these are some of the bigger parts...what was I thinking anyway    This whole thing may be an exercise in futility but time will tell. Thanks for taking a look!!

Bill

[Dreeves]

Bill just checked my cylinders and they are .553 dia with the undercut .312 dia. The heads of my 0-80 shcs are .069 dia.  There is not much room between the head and cylinder wall.  Looking good so far.  I have been playing With the rods and getting ready to fire up the cnc soon to cut them.

Dave

[ths]

Bill, I've been watching this, wonderful to follow.

Cheers, Hugh.

[b.lindsey]

Been thinking about how to do the rod bearing and particularly the pins for the 4 slave rods and one master rod at this smaller scale. Rudy's original design used an .093" dia. steel pin that was threaded on the far side to 2-56. I have already commented that 0-80 is more half the size of 2-56 so I have come up with an idea I will try out this evening.  Basically I will take an 0-80 SHCS ( I should be able to hold the head securely in a 3/32" collet on the Sherline lathe and turn the threads down to just below the minor diameter (.043" or so) thus forming a smooth pin for the rods. I will leave .033" of threads below the head (about 2.5 threads) and also shorten the head so as to fit both the remaining head and threads in the 1/16" wall of the rod bearing. The opposite side of the rod bearing will be drilled to fit the pin diameter closely so that the pin (screw) will be supported on both sides. I am attaching a sketch of how this should work in theory. Any other thoughts, ideas, or even concerns are welcome.

Bill

[arnoldb]

Good going Bill 

I'd say your idea for the screws are good.

Are you going to solder the fixed connecting rod in place, or do you think it will hold it's own with just the curve "locking" on the central hub?  I'd think even a minimal amount of play there will cause it to wear out very quickly...

Kind regards, Arnold