The preview button is nifty . Also to do ^this use tags with less than and greater than signs, not brackets.

Can you grind down the union with a tool like one of these?
http://www.grainger.com/Grainger/DREMEL ... -Bit-1UH81

Tags aren't working for me for some reason.

It's not a CNC lathe, oh how I wish it were.

I'm going to stop by the shop tomorrow (today, actually it's past midnight) and try to consult with the resident machinist.

What Zeus said. You're quite limited in your choice of valves at such high pressures, because valves that use the chamber pressure to hold the seal shut (like a blowgun) become absurdly difficult to use at high pressure. In one of my builds, I used brass 1/4" ball valves at ~1,000psi, but one of the...

Just a note, if you have or can make ceramic feedthroughs, they will work better than rubber.

I think I'll be investing in one of these, great idea! Love to see a demo video

Ohhhh thanks.

Message too short.

What does the "Tap Drill" column in that chart indicate?
I love that site btw

Internal thread bar. Thanks!

I don't think I'll be using a pipe tap, I sorta doubt the shop has pipe taps.

Update! Now at college, with access to a machine shop. I've worked out and got parts for a fueling rig and a pressurized pilot system. Now I'm just having an inner debate... For the end of the piston that has a diameter just slightly less than 0.5... Do I machine my own seal or stretch an undersized...

Hello all! It's been a long long time since I posted here or did much spudding-related. I'm now in college, and have access to a pretty well-equipped machine shop. Mostly I see myself using the end mill (+/- 0.001" in x and y, +/- 0.005 in z) or lathe (+/-0.0005"). Of course, this means I'll be pick...

So... I think I'm finally turning back to working on my hybrid. I'm only missing a few critical components, one being a release valve for the pressurized pilot. If my LaTex algebra is good, only about 136psi is required at 20X. Right now I'm considering a design that I don't think has been tried on ...

Doing what, may I ask?

Suitable springs appear to be available for my requirements, but that's only because I'm working with a .5" valve.

I'm going to need a diagram of your design, al-xg, I can't visualize what you're saying.

That's what I'm working on, Fnord came up with a very similar sketch. Check the force required to hold that piston in the closed position until combustion is finished with a 20X mix. It's pretty crazy.

You are mostly correct, Mimikool. There has however been some recent discussion on how strong the spring needs to be, since there are significant performance gains if the spring prevent translation of the piston until combustion is complete. Of course, that requires a spring about 10 times as strong.

I have a set of standard english sized TiN coated bits, the one I'm buying might be a one-time use, being such an exotic size.

Thanks for the welcome back!