I deleted my old blog, and started a new one, bailingwire.blogspot.com. My old blog was "swearing at Java" and was started mainly because I couldn't find a way to do reprap without dealing with "reprap host" and "the arduino IDE" both of which are Java. I really hate Java, but since I found better way - skienforge and a simple "make" file - I can ignore them and focus on getting things done. So I don't need to feel that way about Java anymore.
I've pretty much settled on 5/16" hardware for the extruder. I want to ream it out for a tapered melt zone, and I think that 1/4" will leave much too little actual thread down at the bottom where the nozzle and heater block go.
I visited the hardware store in Delta today, and they didn't even have brass cap nuts. Their cap nuts where merely "brass plated" which looks about the same (it's shinier) but won't drill nearly as well. And of course it wouldn't conduct heat as well either. They also didn't have the brass jam nuts that I was wanting to use between the fender washers to make the heatsink. I suppose that I don't really know how much difference it would make, steel isn't as good a heat conductor as brass, but it's still *much* better than stainless steel. But they also didn't have a stainless steel bolt that was threaded for the ~3" that I need.
The whole point of using SAE was that I can get it locally for cheap. If I can't get it locally for cheap and have to order off the internet *anyway* I might as well go with metric, right?
But I'd still have to figure the correct size, allowing for reaming.
I think that eventually molten zone volume will be a significant factor as well. I think it'll correspond fairly linearly to "how far do I have to back off the extruder to relieve pressure?" For now a short melt zone is far more important.