[SRT Mike]

I was watching a show on TV, I think it was "how its made". Anyway, they were cutting an aluminum panel that was going to hold a bunch of switches and gauges. They put a finish on the aluminum that looked like a bunch of overlapping circles.

What is that finish called? I thought it was "engine turned" or something? Of course when I google "engine turn aluminum" I get all sorts of links about maching AL on an engine lathe

I have a trade show coming and I want to machine some fixtures in aluminum. They always get beat up so I figured a nice coarse turned finish like that would look OK even after being scratched. But how to achieve it? It looks like it was done with something like a wire wheel or maybe a sanding disc, either in a hand drill or maybe using an angle grinder?

I'm sure someone knows what I'm talking about - any pointers?

[Med-Pac]

Any chance of some pictures? That might help.

Mike

[LinearMotionFan]

Mike,

Here's the "How It's Made" segment that shows that. It's 2:30 into the video.

[ame="http://www.youtube.com/watch?v=MnPRje1khIU"]YouTube - How It's Made Fire Apparatus[/ame]

[SRT Mike]

Hi Mike,

Here is the only pic I could find

[Hennessy]

i don't know what they call the finish but i think it is done with an orbital sander...

[SRT Mike]

Mike,

Here's the "How It's Made" segment that shows that. It's 2:30 into the video.

YouTube - How It's Made Fire Apparatus

Bam! That's it! Thanks so much! .. oh man, I was searching forever it seemed and you go and find it in minutes! Awesome - looks like a sander it is - that's precisely the finish I am trying to achieve.

[SRT Mike]

i don't know what they call the finish but i think it is done with an orbital sander...

Yup, that's it too - I found some sites mentioning using a wooden dowel but they were talking about a jewelers finish and it would take hours with all the parts I'd need to do.... I wasn't sure the best tool but from the pics and video, it looks like an orbital sander and just regular sanding pads will be perfect.

Thanks guys!

[SCRAPWOTSCRAP]

I believe the circular pattern is referred to as "engine turned pattern". Didn't trust my memory (with good reason) so I checked. For your reference:

http://ornamentalturning.net/craft/

[Geof]

i don't know what they call the finish but i think it is done with an orbital sander...

I have a feeling that an orbital sander will give 'fuzzy' circles; try it with a simple rotating disc using a soft backing behind the abrasive.

I have done a very similar thing on a much smaller scale using a pencil eraser and grinding past with the pencil mounted in a drill press.

[mc-motorsports]

"engine turning", it's done with a drill or a drill press, high speed, scotch-brite pads or sandpaper. Simply spin the abrisive wheel about 1000 rpm and press down, move have the diameter to the right, press again and repeat. At the end of the row, move down half the diameter and start over making sure you stay linear for the true "engine turned" look. (vary step over and alignment to preference)

It's old hot rod stuff. You'll see a lot of firewalls in custom cars with the same finish. Don't know where it originated, but from my experience, that's where it's most popular, that at fire trucks! lol

[acondit]

We used to do the same thing (with a much smaller rotating disc) to rifle bolts. It was called jewelling. I used to have a tool that held a small (approx. 1/4" diameter) abrasive imbedded rubber piece that was pressed against the bolt. I may still have something similar for my Foredom.

Alan

[Big S]

I was thinking it would be very easy to do on a cnc mill or router, just like in the drill press only you can program in the spacing and let it do the hard work for you.

Shannon.

[mc-motorsports]

I was thinking it would be very easy to do on a cnc mill or router, just like in the drill press only you can program in the spacing and let it do the hard work for you.

Shannon.

With a spring loaded tool to garantee even pressure, it would work perfect!

[Big S]

With a spring loaded tool to garantee even pressure, it would work perfect!

Excellent idea, you may find that a scouring pad based tool has enough inbuilt 'spring' that it would give the correct finish.

BTW I may actually be doing this sort of finish on my CNC at some stage, my father has already asked about doing something similar on an aluminium frame.

Shannon.

[automizer]

I have done this on my cnc useing a a flat pad sander used for auto body work

[Ultralajt]

Hi!

And when it is done, what shall we do to protect this shiny sanded surface?
Any clear spray coat or just leave it bare?

Mitja

[automizer]

clear anodizing would be a good one

[CarbideBob]

Google search: Engine Turning

[automizer]

something worth watching
[ame="http://www.youtube.com/watch?v=jf5dqUIT-eo"]http://www.youtube.com/watch?v=jf5dqUIT-eo[/ame]

[ALLtra Mach]

I have a feeling that an orbital sander will give 'fuzzy' circles; try it with a simple rotating disc using a soft backing behind the abrasive.

I have done a very similar thing on a much smaller scale using a pencil eraser and grinding past with the pencil mounted in a drill press.

I use a Dual Action Sander on aluminum alot. Geof is right, you wont get an engine turn. Instead of straight down and stepping over,just sand the part like you would a board or anything else. If your just trying to hide scratches, this works great, is much simpler to do and much less time consuming.
I use 80 - 100 grit paper with little or no pressure to just put an even pattern on it.
Engine turning looks fancier, but if uneven it looks "Hack"!