Metal Turning?

OK, I've seen turned metal dash inserts and even a fire wall here and there.

How is this done? Is it something that can be done to rounded sheet metal (cycle tank), or just flat things?

 

Buy the new R&C, Scribe has a good how to in it. (It is the one with the covered bridge on the cover)

 

Basically you spin an abrasive disk in an arbor following a set pattern on the metal. Each swirl overlaps the next by lifting up the arbor and moving the metal a bit each time.You can do round stuff, just harder

 

Thanks fellas. Anyone know of a good shop w/ reasonable rates for this type of work?

 

You're talking about a labor intensive procedure and some heavy bucks.
By the same token, it's easy to do.

There was a very extensive article in the old Tech O'Matic, but it's not there now.

Here's a reprise of a post I did.
That should get you started, or at the least curious.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Machine Turning

Machined turned dash panels were quite popular in the 30's lasting clear up to the late 50's.
There has been somewhat of a resurgence of interest in this today, as witness the commercially available panels.
(if you're not sure what I'm talking about, look at the Auburn Dash Panels in some of the mags - they were usually machine-turned.
Stainless looks especially good when done and aluminum does pretty good too. Just experiment on scraps on both and make your choice.

There are 2 basic ways of doing this at home:
One is to utilize a "Cratex" stick (round, abrasive filled hard rubber) available from MSC (800 645-7270 - for a free catalog that exceeds 3300 pages - thats right, 3300, lots of amazing stuff)
The other is the old time way as practiced by machinists from years past.

Either way requires either a mill, (small mill-drill works great) or a drill press. The mill allows fast accurate work. The drill press will take more time and care.

The mill will be easy, just clamp the material to the table and proceed from there.
The drill press will require a fence clamped to the table that will require moving for each row of circles. If you're careful the work on the drill press will look just as good as the work done on the mill.
If you are using a pattern with an edge that parallels the circle rows, life will be easy.
If not, do the machine turning first and then cut the panel out.
Making the long straight cuts on the panel is best done by the shear at your local sheet metal shop. Costs are very reasonable.
If the ends of the panel are circular have the shop cut close to the line and finish the cut using a bench mounted disc sander or a file. (wood working combo belt/disc sanders work fine)
In any event save cutting out the instrument holes for last - especially if you're using the drill press.

Cratex stick method - Clamp the Cratex stick in your chuck (unless you've got a big drill press, you will be limited to 1/2 - 5/8" in diameter.
decide which way you want the overlap to run (IE: left or right) and with the press at a fairly fast speed make your first circle. (practice on scrap first). Decide on how much overlap you want and make your next circle there. I find that 1/2 diameter overlaps are about right.
Keep the pressure and time the stick contacts the metal the same.
Otherwise you get different looking circles. Having spent some time practicing with your scraps I'm sure you burned a few spots. Try to avoid this on the finished piece.

The old fashioned way - (taught by my Grandfather who was a mechanic/machinist in the So. Cal oil patch - watched him do many amazing things with just simple tools)
Get a can of "Clover" valve lapping compound at your auto parts house. (and I hope you are going to a "real" parts house and not a blister pack store) - (how do you expect to build a hot rod without a good counterman/person/woman/girl - heck I don't know - just be friendly)
This valve lapping compound comes in 2 and maybe 3 grades. Usually its packed in a small double ended can with coarse and fine grades. (mechanics used to hand lap the valves in for a very good seal - with the machines and techniques in use today it's probably not required)
I find that the coarse works best for me - your choice - one can, using the coarse, was enough to do a stainless steel panel that is about 6" from either end of a 32 Ford dashboard.
Get some hardwood dowels at the lumber yard. (I haven't done this, but I suspect if you made your own dowels out of some really hard wood they would last longer than the tyical lumber yard dowels)
You have more size options here as you can easily cut down say a 1" dowel to fit a 1/2" chuck.
Spread some grinding compound on the metal.
Bring your hardwood dowel down and make your first circle.
With a mill you've got it made.
Drill press users will have to have the metal butted up against the fence so as to make straight rows and eyeball the distance to the next circle.
After making several circles you will notice the hardwood dowel will get flared and raggedy on the edges. Shut the motor off and clean it off with a rag. Start the motor and use a woodfile and then 100 grit sandpaper (wet/dry works really well) to trim it back to size. After quite a few circles you may want to cut the dowel down so as to expose a fresh surface. Cut as square as you can and final square it with sandpaper - just bring the dowel down to the paper - motor running - and touch lightly.
Occasionally wipe off the back of the metal as the compound will get under there and make sliding a little difficult.
This can take a while, so don't try to do it all in one day.
If you burn a circle with too much pressure or time you're pretty much stuck. Either make a new one or just live with it.

Clean up your mill/press really good, use a solvent and clean rags as the compound gets into every nook & cranny of the table.

I find that I like the compound method better as it cuts a little deeper and makes a more distinctive pattern that the lighter cuts made by the Cratex stick. Either way the light will really reflect off the circles.

(I have heard of using aluminum rod for this. Havn't tried it, but suspect it would work quite well)

Now that you have a nicely turned flat panel you can cut your instrument holes - need I say to be careful?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

An additional method that came to light after the original posting of this article was to use small stainless steel brushes.
Kind of like a small scale ‘cup brush’ you’d stick on the drill motor to clean out carboned up combustion chambers.
Used dry on aluminum and stainless.

Not sure where you get the brushes, this one was related to me by a guy on the old Roundtable.

If you’re looking for a larger swirl, it sure looks like Dusty’s method in the ‘Engine Turned Sheets’ post is the way to go.

I saw an article in a mag a year or two ago where the author stated “It’s ok to have some mismatch between swirls as that’s how it was done in years past”.
Bullshit....... there were some serious craftsmen in years past and they strived for accuracy, a well done and finished panel.

If you’re gonna do a machine turned panel you owe it to yourself as well as these past craftsmen to do the very best job you can.

Primer is ok, rust is ok, even dents are ok.

Shoddy work.

Never.....

 

There has been a multi part article on this in the last few issues of The Horse Magazine. You do get the Horse, right?

 

i saw that eastwood had a kit for doing it...i wanna say it was around 30 bucks

 

I did it with the dowel method that C9 explained. I used Permatex valve lapping ompound at first. Worked ok. I think it is water based. Then I got some of the clover compound. Worked a bit better. It is greasier- petroleum based. I would still like to try the Cratex, and the aluminum rod methods. Here is a picture of the finished product- not perfect, but alright or my first time I think: