Engine-turned finish to alum. alloy

[xb-60]

This may be something that everybody knows how to do….but then maybe not. It’s called engine-turning, and it’s a polishing or burnishing finish that’s applied to aluminium alloy sheet typically, although it could just as successfully be applied to brass or steel sheet.
If you have a bench drill or pedestal drill press, then you can do it. You need some half inch diameter timber dowel with one end nicely squared, and some valve grinding paste.
If you are applying the finish to a small object, it should be held adequately and safely by screwing it to a larger piece of flat timber.

Smear some valve grinding paste on the workpiece surface.
Position the workpiece on the drill press table at the point where you want to start.
Clamp a suitable piece of timber to the drill press table to act as a guide to slide the workpiece along.
Start the spindle and burnish the workpiece surface. You need to judge the spindle speed yourself (not too fast) and also get a feel for the amount of force required. You are polishing, not drilling.
Raise the spindle and slide the workpiece along the guide so that you will overlap the previous burnished area by around one third. Doesn’t have to be exact; a little bit of variation adds to the hand-done look.
When you have worked the full length in the ‘X’ direction, reposition your guide in the ‘Y’ direction, overlapping the previous row by about one third, and re-clamp.
Continue until you have covered the workpiece surface completely.
For small areas you may not want to use the clamped guide, but the workpiece needs to be adequately held.

A bit of practice on a piece of scrap sheet is a good idea, and light pressure and a subtle pattern is probably a good way to start. If the end result is a little too burnished looking, a light going over with a fine emery cloth or steel wool will tone it down suitably.

The predecessor to this method was hand-scraping, using a hand scraper (who would have thought?). You might have seen it on the slides on old lathes, where it was originally used to enable the surface to retain a small amount of oil for lubricating the contacting surfaces. Probably almost a lost art these days, and it definitely was an art to be able to hand scrape properly.

Anyway, I was trolling around looking for interesting pics and found this close up of CSX2557’s switch panel, which has a dowel-burnished, or engined-turned, finish.
Cheers!
Glen

[davecobra]

Just a side note, Eastwood sells a kit to do it, I did my dash with it.
David

[Learjockey1]

I always have liked the classic mechanicalness of bare metal "engine turned". Some all it "jeweling". Old fashioned classic bling never dies. I was at the Retro Classics Car show over here in in March. There must have been 60 mil of classics on the floor. Many had this technique in the finish.

[Karl Bebout]

Since I was doing several square feet of aluminum sheeting on my firewall and engine bay fender walls, my buddy Mesa Mike used many 2" medium fine grinding discs with a high speed die grinder. He had done his car a few years ago so he knew the process. Didn't really take all that long and came out looking great. I wiped it all down with brake cleaner afterwards and then sprayed it with high temperature clear lacquer to cut down on oxidation. It has the look I want.

[HealeyRick]

I've been a big engine turning fan growing up with hot rodding in the 60's as well as seeing the wonderful Bugatti Grand Prix cars engine compartment. I cheated a bit with the firewall of my Healey engine swap:



and purchased some engine-turned stainless from FPM Metals

[xb-60]

Originally Posted by HealeyRick

I've been a big engine turning fan growing up with hot rodding in the 60's as well as seeing the wonderful Bugatti Grand Prix cars engine compartment. I cheated a bit with the firewall of my Healey engine swap:



and purchased some engine-turned stainless from FPM Metals

Out of interest, how much does the sheet cost?
Cheers,
Glen