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Thread: Swirl mark finish
06-24-2007, 12:53 PM #1
How is the nice swirl mark finish made on a flat surface?
06-24-2007, 12:56 PM #2
There are many styles of "nice swirl mark finish." Can you be more specific?
06-24-2007, 01:02 PM #3
The finish I am trying to describe is concentric circles. I tried to use a wine cork in my mill collet with lapping compound. put downward pressure then move the table 1x dia of cork then pressure again, repeat. Wish I had a picture to show you. I have seen this finish on a bank vault door ( much larger scale than I am trying)
06-24-2007, 01:05 PM #4
I'm guessing that this is close to the finish you're thinking of. Only time I did this was on the scale cover for my mill/drill. I don't have a better picture. http://i5.photobucket.com/albums/y18...g/DSCF0010.jpg
In my case I just used a 1" dia piece of plastic and used double sided tape to hold a piece of emery cloth. I did have to change the emery cloth a few times. I spaced them out equal using the mill of course but some do it by hand.
On large areas some use a round sanding disk on a hand drill. I think there's a few ways to space them out to get different effects. I wasn't so sure when I tried it out, I mostly did it just to hide future scratches.
06-24-2007, 01:07 PM #5
The term is Engine Turning
06-24-2007, 01:11 PM #6
Thanks to SND and John for the proper term
I will try the emery cloth
06-24-2007, 01:12 PM #7
Sorta like this eh:
Looks sorta pretty on an airplane cowl but I much
prefer the appearence of a real hand-scraped
surface on machine tools.
06-24-2007, 01:20 PM #8
That finish can be done with a drill press or vertical mill. You can use a wood dowel with a small abrasive disc on the end. You can also use a brass or cast iron rod and various grades of lapping compound. It depends on the material you are finishing. The key is to overlap the circular patterns with uniform spacing. A very slight tilt may help, too. I built a jig once that used a coarse pitch power hacksaw blade to quickly index the part in one axis.
I once used a Bosch random-orbit disc sander on a piece of steel plate, the apron on a Di-Acro shear. It took off the light rust and left a very nice random swirl pattern.
The ultimate swirl finish is found on high grade antique pocket watch movements. The rotating lap was moved by an ornamental lathe or straight line engine in complex patterns. Sometimes the finish was made two-tone by gold plating and lapping through parts of the plating to the underlying silver color metal.
Google "engine turning" to find a wide range of definitions and descriptions. Some will answer your specific question, and others will lead you to rose engines and straight line machines.
06-24-2007, 02:04 PM #9
I will try your sugestions, lots of information on the web now that I know the correct term
Thanks to all
06-24-2007, 02:12 PM #10
06-24-2007, 02:50 PM #11
cratex also works well, as will a small wire brush
06-24-2007, 03:19 PM #12
I use a piece of 3/4" Tufnol( but you could use bigger) with a slot sawn in the bottom on the centre line, fold a small piece of emery cloth in two and slide it into the slot, folding the cloth that sticks out back down onto the Tufnol creates a little disc of emery. Quick dabs with a pedestal drill work best, don't allow the material to dwell on the work.Regards Tyrone.
06-24-2007, 04:06 PM #13
You can buy rubber abrasive rounds (they look like pencil erasers) to mount in a holder in different diameters and grit. Do a search. The rubber abrasive does a better job and is more controlable.
06-24-2007, 04:31 PM #14
Pencil erasers work on soft materials and look good on a small scale.
Cratex stick works on a larger scale and you can chuck in directly. Dress the end with coarse sandpaper for consistancy.
Or you could roll up a piece of sand paper and chuckk it.
Or you can get a Ro-Lok kit and use the non-woven fabric abrasive disks.
On a larger scale there an angle grinder and a soft pad sanding disk.
Stick and valve grinding compound has already been mentioned.