Fine finishing plate stock

[Donleybill]

Q Has anyone tried to use a flapper disk abrasive pad on their vertical mill? The base of the engine I’m building was originally Blanchard ground which looked ok. After months of building on top I’ve managed to upset it’s original surface finish. My engine build is about finished and I need to address the surface finish of the 1/4” plate 302 SS stock. I don’t want to surface grind. I would rather see fine spirals patterns across the plate. Don’t want to color paint.
Disk sanding on a milling machine is not what it was designed for. If the ways are covered and I carefully clean the milling machine before and after why not? I‘m will double side tape the plate stock to the machine table. Attach a flapper sanding to the spindle. Turn on the spindle and hopefully end up with great results. Is this too stupid or what!
Bill

 

[Charles Lamont]

A flapper will round the edges - a sure sign of poor workmanship.

 

[kiwi2]

Hi Bill,
I can vaguely remember from years ago someone gluing a circle of scotchbrite(?) to the end of a piece of 1/2"(?) rod. This was mounted in a mill and plunged down onto a flat metal surface to produce a circular mark. The work was then moved 1/2"(?) and repeated. This left an attractive pattern on the metal. I can't remember if the circles overlapped or not. I'm sure someone else will know more about the process.
Regards,
Alan

 

[Drawfiler]

Yes overlap, you can use a circle of abrasive paper glued to the disc and slightly angle the spindle. Look up ‘Engine Turning’

 

[Apprentice707]

I have used a piece of suitable sized wooden dowel cut square to the axis and dipped in fine (or very fine if the material is non-ferrous) grounding paste, It will need recharging with paste from time to time and is best done in a vertical milling machine or a drill with a compound table. When finished wash off with a suitable spirit.
If you feel adventurous and have lots of time you could hand scrape the surface which should look good after about 20 years of practice!! I can't do it but I admire people who can.

Good luck and stay safe.

 

[Charles Lamont]

The OP said it was made of 303, an 18/8 stainless. I don't think I would want to try scraping that.

 

[Joe]

You say you don't want to surface grind which suggests to me you have that capability. If so can you rotary grind the plate ? Mount the plate to a rotary device and grind whilst rotating and only in feed or out feed the grinder, no left/right traversing.

Cheers,
John

 

[Mike Henry]

Would abrasive brushes like those from BRM work?

http://www.brushresearch.com/brm/abrasivebrushes/

 

[Apprentice707]

The OP said it was made of 303, an 18/8 stainless. I don't think I would want to try scraping that.

Point taken.

 

[Donleybill]

Would abrasive brushes like those from BRM work?

http://www.brushresearch.com/brm/abrasivebrushes/

Thanks for the tip. It would work I’m sure but this tool is very pricey.

 

[Apprentice707]

Would abrasive brushes like those from BRM work?

http://www.brushresearch.com/brm/abrasivebrushes/

That would scrub the front doorstep eh?