Sintered bronze & copper discs

[agemcutr]

Ive just spent all night(finished at 1.23am) making a copper and bronze sintered high speed polishing systems disc. I now have to add the tin centre glue it too a base disc machine balance and test it.Ive added tin and graphite to the mix to soften the finish.
Its eight in OD with a 5 inch ID and a five inch tin centre fixed or removable for a type metal and tin centre.Hope that makes sense. I will add photos of the results tommorrow
and be demonstrating this disc at Mingara on the central coast this weekend.

Regards Anthony

[From Rock to Ring]

Looking forward to the pics 

[agemcutr]

Its 11.52 pm and all the machining and melting is dont. Ive noticed my hands are black from handling the graphite inpregnated discs. a good sign and they feel a little slippery which is what i wanted.(note to self dont scratch nose or nuts)There ready to glue together
then the final diamond machining. I had to repolish and shape an old diamond tool to siut this job,that took an hour or more.So Im sitting back with a Mudgee mead and panadol before I go to bed. More tommorrow.

Anthony

[bjhodgkin]

Ahhh - just worked out who you are gemcutr.

Bought one of these at the show after a recommendation from one of my mates in the Central Coast club who was really really impressed with his & just off to try it out now. I am just still a learner (i.e. not much to compare results with) but will hopefully have some results to report back on soon - I suppose if I can a polish on the stones it is doing well and a lot better than my really old (& not that flat) copper laps and Perspex lap I have been using to date.

Regards

Rob

[bjhodgkin]

Tried it out and my first impressions are that it is a really good system. I was paranoid (ok terrified) about cross-contamination but followed the stepes you gave me and it worked really well.

The only scratch I ended up with was one I had obviously put in prior to going onto the new combined disc and didn't get out at the appropriate time (only a tiny one - possibly still in there from 600 grit).

Only things I need to do now are:
- get that light you recommended as my lighting isn't that great & probably why I missed the scratch, and
- get used to cutting at the higher speeds which is amazingly fast with my other 1,200 grit lap & can't really see my 600 will get used at all now.

Also, I am happy you gave me 16,000 grit for the pre-polish as 3,000 would have been way too fast with the higher machine speed and my beginners cutting skills.

Will start to post some pics as I finish some more stones.

Rob

[agemcutr]

I havent cut a full stone on it myself yet.Halogen is both a blessing and a curse. You cut better and see all with it but stones you cut prior to this light dont stack up.
I gave you 8000 i believe as a prepolish for the copper, just to slow you down a little as we discussed.Glad it worked out well for you.Perhaps a three in one next year at Mingara?Still working on the mold for it thou.
Im off to cut a pear shape tourmaline to test the system.

Regards Anthony

[agemcutr]

Ive been using the system now for most the week and its the best result of all my wheels over the years. The additives to the copper have made a very smooth running and silky finish with very little scratchyness that you get from normal copper at higher speeds.It also performs well at low speeds. Ive noticed that its alittle bit more thirsty than other laps and needs a bit more baby oil between polishing paste.Im using the lap inserted in the middle of a sintered 1200 bronze lap.Ive found that this lap can be used at diamond cutting speeds
of 3000 RPM but works best at 2000RPM.Ive found however that the tin centre is a little hard for softer stones,but still gives perfect results and gives the best flatness ive seen outside diamond cuttting and the 200,000 polish a competition finish on every facet.
Ive tested the bronze as well. Its gives similar results but is a bit harder than the copper.This would be best for sapphire /CZ cutters ,but would still work on other stones.
Its perfect for quartz but takes alot longer than other stones. I would sudjest a 50000 finish for quartz. Ive also made a changable lap system for the eight inch system for a custom setup IE soft tin ,type metal and hard tin lap inserts.Im also testing a new alloy centre lap,on the soft side but has excellent diamond holding properties.

Regards Anthony

[From Rock to Ring]

Thanks for the pic