Axeman,
I had a feeling it would be tungsten. The connectors I am thinking of using are sold here in Australia as "BP" Mains Connectors. Link on Ebay is
http://www.ebay.com.au/itm/40A-Mains-Cu ... 5c1&_uhb=1 You can buy them with single screws for active and neutral and double screws for earth. Maybe just filling the screw cup with silicone would be sufficient to stop arcing to the chassis.
As I look deeper into the guts of my laser I can't help wondering how it was even deemed to be safe when it was sold. I came to own by a rather sad but circuitous route. The secondary school I was working at originally purchased a 40 watt machine from a vendor here in Australia called Red Dot Machinery in Sydney. It was a reasonable machine with a 500 X 300 capacity and motorized Z table. We had numerous problems with it though and although the vendor promised telephone support before we purchased I was never able to speak to the guy on the phone. Everything was done by email with usually a two day turnaround to get replies. We paid AU$8500 for what was essentially a $1500 machine. It arrived direct from China so the guy never even checked it before we received it. Because students would be using it I specified that it must have an interlock on the lid but guess what? No interlock, and even after I fitted one I still burned myself trying to solve issues with a failing stepper motor. We eventually sent the machine back while it was still under warranty and what the guy sent us as a replacement is the machine I eventually purchased from the school for $200. We never did get it to work due to incompatible software and what I suspect was the wrong dongle for the machine. I eventually lost patience with the vendor and threatened to put the whole matter in the hands of the Education Departments legal department. Our intrepid legal team took six months to send the company a letter of demand which the vendor ignored and sent back with "recipient no longer at this address" scrawled on the unopened envelope. He is still trading though!
The laser I now have arrived with broken plastic bearing mounts for the Z adjustment, a manual adjustment instead of motorized and the general build quality is appalling. There were loose screws, washers and nuts in the bottom of the chassis and mismatched screw sizes on components. I have so far replaced all the Z screw mounts, fitted an new fully machined beam combiner, upgraded the tube mountings, mirror mounts and of course I have fitted an AWC608 DSP. Basically, I am just using the chassis, the XY stage and some of the electrics. One bonus is that it came with a working water radiator, air pump and rotary table.
Regards,
Preso
