May 29, 2008

Close enough....
     is good enough
        when you got a Taig

... let me explain that.

I haven't written much about making these throttle quadrants and I'm just about finished with them now. But that's getting ahead of myself... but I guess I'm at that point already...ahead of myself.

Well, at this point in time, just about all the pieces have been routed out of aluminum (amazing how that stuff cuts with a router... like budda,) practically all the holes have been drilled and not much left to do.

The point of discussion tonight is the friction knob. You know, the knob you tighten to keep the throttle levers from moving fore and aft. I wanted to get a nice set of aluminum knurled knobs from McMaster-Carr.

Started flipping through their online reference book and found something that was REALLY close to what I thought that knob should look like. Close, beacuse, one, I couldn't get it with the 10-32 threaded stud that I wanted and two, the neck on the knob itself was about twice as long as I had wanted it to be. Just a few months ago I would have either bought it and dealt with it "as is," or continued my search for the "perfect" knob. Well, now is now, and now I have a Taig Micro-lathe and "close enough" is something that I can change.

Plunked my money down for two aluminum knurled knobs with unthreaded holes in them and two 1 1/2" long 10-32 threaded studs on Tuesday. Got my package on Wednesday. Went to work on them on Thursday.

Tonight was all about the Taig Micro-lathe. First I chucked each of the knobs in the lathe and cut the neck down to the size that I wanted. Finished each with a beveled edge and then took 200 grit sandpaper to them to smooooth out those edges.

The holes in the ends of the knobs were way too big. Found a small piece of 4130 tubing that the 10-32 stud just fit inside of. One small problem, it was too large for the opening in the bottom of the knob. Notice I said small problem. I cut two small pieces off of the small piece of tubing that I had, chucked them in the Taig Micro-lathe and turned down the outside of them until they were a snug fit inside the knob's hole. Using a parting bit I cut each one off to size. Mixing up a small batch of T-88 I glued the "bushings" into each hole then glued the threaded studs into each "bushing."

Close enough, when you have a Taig Micro-lathe is good enough 'cause you can make it dead on in a matter of minutes.

This was the first time I really used the lathe to craft a piece for the biplane. Had a great time learning and working with it. If you're building a plane and you're thinking about getting a lathe, or maybe you aren't even thinking about getting a lathe, do yourself a favor and pick one up and start learning on it as soon as you can. Well worth the money, and you'll get almost the same kick out of using it as you do welding with O/A.

I'll be uploading some photos of the throttle quadrants and write up a brief discription of what I did to make them. I spent about $50.00 in materials, if that, and saved about $500.00 off the list price of two throttle quadrants. It's all about money... oh yeah.. the learning thing too.

May 30, 2008

Levers and knobs....
     routing and bending...
          how I made my throttle quadrants

Above May 29th post was putting the cart before the horse.

(pictures to follow)
Learned a lot and saved a lot by making the two throttle quadrants for the Skybolt. Never thought that I would be making something like this. It was one of the farthest things from my mind... sorta like cutting tubing and welding up a fuselage.

Got the idea from Scott (Scottly) from the biplane forum. He started a thread discussing how he went about making two of these for his Skybolt. Didn't look that hard to do. I asked a few questions and got started on them.

You'll want to take a look at the old Skybolt Newletters that Mac MacKenzie printed out for a few years. You'll want to take a look at Series 3, Volume 3, page 12 and 13. That's your starting point.

The material that I used was 6061 aluminum and 2024 aluminum. All of the pieces were cut from the softer 6061 aluminum except for the back plate which was cut out of the harder 2024 aluminum for it's rigidity.

While waiting for the material to arrive I laid out all the pieces on the DeltaCAD program that I have and printed them out. I gave the files for the larger levers to the guys in the Engineering Department at work and they printed out the DWG drawings that I gave them. (thanks guys!)

I made a few jig for holding the pieces of aluminum and to give them a uniform shape. I cut these out of 1/2" plywood. I used the larger jig to route the larger pieces, of course, but I also used it to route the top and sides of the smaller pieces that I used as spacers for the top-inside. Using the one jig allowed me to route these to the exact same shape as the larger front and back plates, keeping things uniform.

After I routed out all the aluminum pieces, I glued thin sheets of .010 brass to the sides of the upper spacers (I found these at a local hobby shop.) Once they dried I routed the brass the same as I had routed the aluminum, using the jigs. The bottom spacers I cut out individually and then drilled the hole through the centers.

Let's see... all the aluminum pieces are cut out. Still need to cut and bend the throttle levers. I wrote a little about that earlier. You can click here to go to that page. Long story a little bit shorter... don't try cutting your 5/8" wide levers out of .o71 4130 flatstock. It'll cup on you like a potato chip. Do yourself a favor and order strips of 5/8" x .071 from Aircraft Spruce. By the way... I haven't drilled or bent those levers yet. Been working on the fuselage. Maybe I'll get to it this weekend.

I still need to purchase the throttle lever knobs. You can use just about anything. McMaster-Carr has a selection of knobs at a reasonable price. I did a search and found a place out West that'll make custom knobs. Just a little bit more money but it'll give it that custom look.

June 2, 2008

Scrap aluminum....
               and the strange feeling of being...
                                                     marginal at best

It just didn't feel right tonight.

What didn't feel right ????
Nuthin' !

It didn't dawn on me until I turned out the lights and headed up stairs to make a call to Denise. I wasn't happy with the scrap aluminum, er, routed pieces that I had worked on tonight. But somehow I knew I wasn't going to be. Hmmmmmmmmm ??? What the hell does that mean ?

I was putting in time on the plane. But that was it ! It was just time. The cutting out of the jigs for the spacers. The routing of the pieces. Just time.

What's to be taken away from tonight... what learning ?

There's got to be something in it for me other than a night of making scrap aluminum.

I had every good intention of putting in a few good, productive hours on the biplane.

I had a plan.

I had set out to make those jigs and get as many of those additional spacers routed as I could in two hours. Maybe that was the problem, er learning. It's not about how much we can get done in the amount of time we have... it's about how much we can accomplish in the amount of time that we have. And, getting those jigs made and routing out several unacceptable aluminum spacers isn't accomplishing a thing at all. I would have been better off taking my time making a few nice jigs than to "rush" through slapping together something that I "knew" was going to be marginal at best.

Tomorrow... plans on making a nice set of jigs to route my additional spacers for the throttle quads. And if I get to route a few of them out it'll just be that much more that I will have accomplished.

June 9, 2008

Fit ....
          and finish...
                              ...the final five percent

Each part... a microcosom, or should I say a "micro project." Wikipedia's Wiktionary's definition of microcosom: a smaller system which is representative of or analogous to a larger one. In reference to a Radial Skybolt project... the smaller system, the individual components, parts of the whole.

Anyways... my point, we're always hearing about, and talking about, 90 percent done 90 percent to go. It's the same as my "fit and finish... the final five percent" intro above.

I've been working on these throttle quadrants for what has seemed like forever. Learned a little about routing aluminum, starting to learned how to use the lathe, actually seeing bend allowance-set backs-site lines really do as they say in the books.

There were/are a lot of pieces to these two throttle quads. Each piece adds that much more time to that particular microcosom. Each of these quadrants have about 2 dozen pieces to it... all with pretty close tolerances. (Read that as more time.)

They need to have a nice fit and finish to them. (Again, read that as even more time.) You know... more so than the other parts that we're anal about... this is anal taken up a notch or two. Not a bad thing when it's something that you'll see each time you fly the Skybolt. These are sorta like little works of art. Call me crazy, 'cause I am.

Where was I going with this ???... oh yeah, the "final five percent." I always wondered about that 90 done 90 to go bit. I always thought it was just a lot of little stuff, still left to to do on the plane. As I sit here writing this now, that's now how I'm seeing it.

My work on the throttle quads, this microcosom of sorts, has opened my eyes to the larger picture, or macrocosom.

Cutting out all those parts did take some time, sure... and that's understood. But all this sanding and sanding and sanding, fit together and take apart and sanding and sanding and sanding, fit together and take apart and sanding and sanding and sanding... well, I hope you get the picture. This final fit and finish, what I see as five percent of the microcosom's size, is taking me 90 percent of the time to do. It's gotta be what others are talking about when they say that... you know, that 90 percent thing.

I just hope that all these microcosom fit and finishes are adding up towards that "final" five percent.

There's more to see...