Help me build a conical fermenter

So, I was dropping off cans at the recycling/scrap place and was sort of being given a tour of the place when I spot a Stainless Steel funnel. I asked if he sold to customers and he said yes, so I bought the beginnings of a conical fermenter. At $1/lb, it came to $13! He was pretty sure that it came out of a milk parlor.

It has an 18" diameter across the top and a 4" diameter hole at the bottom with a v groove for some type of clamp. The total volume is over 9 gallons and using some rough measurements, I believe it is a 60 degree slope which is ideal. I need to scrounge up a lid, valves, and over various parts but was looking for some direction as to how high the rotating arm should be. Also, I'm looking for suggestions on how reduce the 4" hole to something a little more manageable and thoughts on what diameter lines I should use (1" ball valves, e.g.). Do you think this will work? I'm not too worried as I can always sell it for scrap!

check out this thread...yuri already posted a guide:
https://www.homebrewtalk.com/f51/diy-conical-fermenter-14855/

I would just weld a round piece of SS to the bottom and then weld in a fitting for your ball valve on the bottom. For the racking port mine is 4" from the bottom. Same thing; have a fitting welded in that will accomodate a threaded nipple for your specific ball valve.

I would use 1/2" ball valves for no other reason than 1/2" seems to be the standard.

Thanks for the mention, scinerd.

Don't plan on having it hold any kind of pressure unless you'd like to do a ton of engineering (I gave up...but that doesn't mean it's not possible). Just be satisfied with a lid that seals well, and do your transfers via pump or gravity. I really like the 1" dump valve on mine. Look into tri-clamp fittings to make it really snazzy.

I've read Yuri's post at least twice now and it's helped a ton and I haven't even started yet! Thanks for taking the time to put that together Yuri!

I'm surprised that a 1/2" dump on the bottom wouldn't plug. Has anyone had trouble with it plugging up?