www.nightvisionforumuk.com

Machining pure copper is probably like trying to slice chewing gum. Look at the different finish to the ends of the copper and ally rods, and that was after several attempts. I'm getting them nice and easy from ally (circled) but can't get anywhere near a decent copper one yet. It folds or chips easier than it cuts.

It seems a special copper is needed for machining, it's on order and pricey too. Still waiting for LED-TECH.de to restock the 16mm Oslon Black SFH 5715s stars so I can leave as much copper as possible in place to soak up the heat. If anyone is sitting on a few puh-lease let me borrow or buy them. Pretty please even.

I have several Ahorton lenses if anyone wants em @ £13 ea.

I hate to say I told you so about machining the copper..............

George

BLIMEY! do you have enough drivers?

paulham wrote:BLIMEY! do you have enough drivers?

I know it'll shock some of you but....
































I'm optimistic sometimes.

It's the 'Some Bloke P60 Drop-in Company'. Mind you don't turn into a multi-national conglomerate, Dave.

George

Dave, so far I've not tried turning copper but I guess your problems are with the rpm and the cutting tool itself - I would think a sharp hss tool with plenty of clearance and run at medium speed with a fairly light cut. Hopefully a bit of experimenting will result in a decent finish. The work may be flexing a little against the tool which could give some chatter and a poor finish, if you could use a live centre that would keep it more rigid.

terry1001 wrote:Dave, so far I've not tried turning copper but I guess your problems are with the rpm and the cutting tool itself - I would think a sharp hss tool with plenty of clearance and run at medium speed with a fairly light cut. Hopefully a bit of experimenting will result in a decent finish. The work may be flexing a little against the tool which could give some chatter and a poor finish, if you could use a live centre that would keep it more rigid.

I'm running at it's slowest speed now and very close to the headstock with the rod all the way through the spindle hole so it's not moving in the jaws. I found it better taking a slightly thicker cut to get some kind of flow but it's just happy.

I just jumped in and bought "copper" rod instead of machine grade copper rod. My mistake that I have learned from.

I wonder if the "machinable copper" will still have the same thermal properties?
Everything you might want to know about machining the different copper and brass alloys. Long read but lots of good info.
http://www.copperinfo.co.uk/design-and- ... alloys.pdf

Dave, I had a quick look around and found:
http://www.cnczone.com/forums/general_m ... shape.html.
The general consensus seems to be very sharp tools, high rpm, light cuts and keep it cool - suggestions include WD40, milk and vegetable oil.

Cheers chaps.

I already have better machine grade copper on the way - which has excellent thermal characteristics. If I can't get on with it I'll fall back on plan b - aluminium ones which is still much more thermally conductive than brass - especially when the standard brass pill base is only 0.5mm thick between the star and the driver cavity.

Ally is of course no good for soldering which is why it isn't used for many LED pills but there are other ways of fixing the driver whilst maintaining electrical continuity.