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How to get a stunning finish on Brass

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AdeV:
I've been turning some brass the last couple of days, and had been getting very rough finishes using my new Glanze indexable tooling. A couple of weeks back, however, I'd bought a couple of inserts for aluminium cutting from Chronos: Linky thing. Figuring that brass is softer than steel, it had to be worth trying it out. And, like wow (as a Californian might say):

After a simple turning operation, the machine marks are almost invisible to the naked eye. This pic is after a 0.005" cut @ 400cuts/inch (2.5 thou per revolution - the best my lathe will do):


So then I tried a facing cut... I didn't quite cut all the way through the marks, but you can see the quality of finish:



Suitably impressed, I broke out another product I recently bought, having seen it on here:



After applying a smear on the end & letting the lathe spin it for maybe 30-40 seconds (any more an I lose patience), this is the result:


It was proving quite difficult to photograph with the flash (the light just bounces off & goes somewhere other than in the camera), so I tried one without:


OK, it's not quite as good as a bathroom mirror, but not half bad for 5 mins of turning & half that polishing....

Bogstandard:
Ade,

If you want really superb finishes and a versatile tool as well, invest in a profile tool. They can cut in all directions.

I have been using one for years now, and they really are a good addition to your arsenal.

http://rdgtools.co.uk/acatalog/PROFILE_LATHE_TOOLS.html

The big plus is that when one area goes dull, you just turn the tip a few degrees and you have a nice new cutting edge. You can turn it say up to about 20 to 30 new edges before the tip needs replacing. If you are very careful, and a real cheapskate, you can in fact resharpen them for use with brass by just stroking the top face across a water wetted diamond lap. DAMHIK, and guess who's a cheapskate.


John

Powder Keg:
You can also use some fine grits of Emery paper before you polish it up to help get rid of tool marks.

John Hill:
Do not use a rag to apply polish to work in a lathe while it is running, in fact do not allow rags anywhere near rotating machinery!

Use small scraps of newspaper to apply the polish!  If it gets snagged on the work the news paper will tear and you will still have your fingers!  Besides, the paper fibres are rather hard and bring up a nice polish in no time at all.

AdeV:
Bogs - I nearly bought one of those last time I bought some tooling, but didn't in the end as I was already spending more than I ought... but I will definitely get one next time. I guess the real point here, however, is that when cutting brass (or Ali), one needs an absolutely razor sharp tool, which most indexable tooling simply isn't.

Powder Keg - the machine marks simply aren't there (compared to every other bit of turning I've done). I expect a bit of 1000-1500 grit work would help, but I don't have any such paper... so it's straight to the polish for me.

John H - Fear not! I used a microfibre "pad" to apply the polish. Had it got caught in any way, it would simply rotate out of my hand, causing no injuries and only some minor cursing. In the event, it didn't even do that, so all was well. Nice idea about the newspaper though, I must try that out.

All good hint & tips chaps, keep 'em coming!

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