Hatz Biplane Association

This picture goes more to the finished product than the process but reflects that a fairly complex cowl can be "turned" if each step is undertaken in the right order. There were a couple of starts and restarts when doing this projec

Excellent posts. Thanks for sharing your knowledge gents.

Bill

I believe I posted my method for the Hatz Classic a year ago. But for the cowl a low abrasive 3M 2"disc in a drill press was used. Prior to final assembly a grid was marked on 1" centers. The turning begins at the bottom rear point to insure that the lay of the turns overlap like fish scales. Each suffering turn overlaps the one blow and the row behind. The EAA Hints for home builders has a slightly different approach but feel mine had a some preference for me. There were a half dozen or so beyond the reach of the drill press but with care and slow speed turns were successfully applied to the clamped cowling pieces

Thanks everyone for your in;put.

Wot kinda playne iz zat your drivin ,Mark---bootiful---Jerry

When I wanted to put an engine turned finish on the instrument panel of the Corben Super Ace I built several years ago, I purchased a kit from Eastwood. http://search.eastwood.com/search?p=KK& ... 20Kit&rk=1
It's a time consuming process, depending on the size and spacing you decide on. If you have access to a mill it's much easier to keep the spacing even, otherwise you can use a drillpress with a fence to keep the work straight. Just be careful with your spacing. The Eastwood kit uses a hard rubber rod and mandrel and requires very little abrasive.
If you're going to finish a panel that will have a bunch of holes in it, it's a lot easier to engine turn the rough panel before you drill or punch all your holes. The tool has a tougher time right on an edge.
Have fun,
Mark

I've heard of people using scotch brite or emery paper on the end of a wooden dowel modified to chuck up in a cordless drill. If using a drill I'd suggest cordless because they usually have better speed control.

The best results I've seen, and one of the "safest" methods is to use valve grinding compound (paste) which comes in various grits. I think the finest would do it and its available at auto parts stores. Normally the paste is put on the valve seat and the valve (like in a car engine) is turned with one of two tools. One is not much more than a dowel with a suction cup on the end turned back and forth between your hands as if you were rubbing your hands to keep them warm. The other tool does the same thing but it is like an old crank egg beater and when you crank it the rod coming out of it with the suction cup on the end turns back and forth about a half turn or so. A good idea would be to make a "lower guide" of some type to keep the suction cup (which in this case has the valve grinding compound put inside of it) from "walking around" on your metal. A board with a hole in it the size of the rod which rotates back and forth with some pads on one side to raise it up of your metal just a little should work and keep the suction cup rotating in the same spot so the round burnish marks are all nice and round and not "wobbled". If the suction cup is actually "sucking" to your metal you'd want to make a hole in it so it did not stick.

There are probably many more methods that would work nicely, maybe even better than what I described.
It probably goes without saying that I'd try a couple methods on scrap and find which works best for each persons skills.

Hope this adds,

-Jackal

Hi Ron,
There is an Eaa video in the homebuilding section, try this, http://www.eaavideo.org/video.aspx?v=595068183001. If the link doesn't work, it is about three pages back in the listings. The Scotchbrite discs come in various diameters. I don't think you want to use a hand drill for this.
Al

Can anyone tell me the procedure for applying the circular brushed pattern on aluminum. Have seen several with such on engine cowling and instrument panels. Assume must be using something such as a wire brush on a drill. Interested in techniques for maintaining consistent pattern during the process too.