Need Help Building Equipment

I couldn’t find a decent olympic bar/barbell here in Brazil, therefore I’m trying build one myself. I know I know what you’re going to say: “buy a new one, it’s cheaper and more secure”, or ?buy a used one, it?s even cheaper, don?t waste your time? but unfortunately they don’t sell good olympic barbells in my city (northeast of Brazil). In fact, they don’t sell any kind of olympic barbell in the state where I live, not even the cheap chinese ones. The few bars they sell are crappy and very, very expensive.

I’m going to use a raw steel bar. I’m making the knurling and collars in a workshop/metalworker near my house. They have modern equipment and professional leathers. My first prototypes were made of stainless steel (grade 304), but I realized that it was’t strong enough to support a lot of weight.
I finally could find a steel bar that I think is strong enough (grade 4340), but there is an issue: there?re only two bar diameters available, 1" (25.4mm) and 1 1/4"(31.75mm).
My questions:

  1. Is there a problem with the 1 1/4" diameter? I have small hands and I’m worried that it is too thick.(I’m only going to use the bar for compound movements like squat, deadlift and bench press ? non-olympic lifts)

  2. Does anybody know if steel grade 4340 is really strong enough?

  3. How do I fix the inner collars on the bar? Welding? I’m afraid that welding would weaken the bar (fracture points). Bolting? Do I have to drill a hole in the bar?

  4. Since I’m not doing olympic lift movements, I?m not planning building the revolving sleeves. In fact I have no idea how to build them. Are rotating sleeves really essential for non-olympic lifts like squat/deadlift/bench press etc?

  5. What’s the recommended coating to protect the bar against rust? Chrome? Zinc? How do I make it? I know chrome is very slippery.

  6. How weak are bars made of raw steel (not heat treated)?

The weight plates (32mm hole) will be custom made in a local metal workshop/factory.

I know that building a bar myself sounds ridiculous and waste of time. Buying a good barbell and weight training equipment is not a problem for you who live in USA or Europe. Plenty of quality equipment and good prices. You have even Craigslist. A lot of good options. Unfortunately in Brazil fitness equipment is crap and very, very, very expensive; even more expensive than in Europe. So I have to build them myself (actually not myself). Don’t know why the top companies (Ivanko, Pendlay, Eleiko etc) don’t sell their products here. Brazil would be a great market for them.
Would Appreciate your opinions and suggestions.

P.S. I would appreciate if you guys post (or send me pm) close pictures of your barbell’s knurling. I like the deep and coarse/aggressive knurling but I’ve never seen the knurling pattern of the top barbells (Ivanko, Pendlay, Eleiko etc.).