Some notes on how I design things. Some people make detailed 3D cad models of their complete vehicle. I do some dimensioned drawings, but I don’t make them a complete detailed cad model. The drawing below was my layout for the Jet Vanes.
This drawing was done in Rhino to scale. but as a flat 2d drawing. When the vane mount got welded to the exit cone if was about 0.1875 too far down. This caused me to redo my vane bearing mounts and redo the jet vanes as the bearing is now 0.2” farther from the exit cone.
Once I have a scale drawing of the parts I make a simple dimensioned drawing I can take out to the shop or use to generate CNC code for the lathe. I don’t have a good lathe CAM program so all the Lathe CNC code is generated by hand or by writing a program to generate the CAM file. The CAM generation on the mill is automated from the drawing.
This is the drawing for my new corrected vane. I got up this morning and went to two places, IMS to get more 316 stainless shaft to make vanes out of, and to Marshals Industrial hardware to get some more carbide end mills to cut the stainless. So after working from 8 am to 1:30 am I have the following:
The three parts on th left are not yet destroyed. All the parts on the right are toast in various ways. The four that look relatively complete are done to the original drawing and are now the wrong dimension. Some of the bad ones have the wrong bearing dimension (They are loose on the bearing), I had a problem in my hand crafted lathe code where I made 4 exact errors…. The other two are the result of milling problems, the new carbide bits I got today just aren’t lasting. MY last set that I ordered from MSC would do two vanes before they were dull, the ones I picked up today last for 1/2 of a vane. So since I went through all my carbide tooling I though I’d try a big 3/4 TAIN coated HSS end mill, real slow…. The one in the middle left with the notch is the result of that experiment. The bit cut just fine … for awhile then it suddenly welded it self to the work piece and when I based the mill to recover it bent the vane. The three parts on the left are done with the lathe work (sort of) and now need milled. The one on the bottom left that looks like it was gnawed by a rabid squirrel is the result of trying to part off the vane and having the parting tool die. I really should not be parting solid stainless on my Lathe its just not rigid enough, but I don’t have the shop space for the proper tool, a metal cutting horizontal band saw. I even tried the Armstrong method, I bought the highest quality hacksaw blades I could find at home depot and after two strokes the stainless removes all the teeth.
As a general rule I don’t wear gloves near machine tools, its a good way to loose your hand. So in the last 24 hours I’ve bled from 5 of my 10 fingers.
The vanes are bieng used in a hot oxygen stream so I need the maximum oxidation resistance, otherwise I’d use 303 stainless a lot easier to machine. Did I say I hate Stainless? Hopefully today will go better…