Arbor specs/terminology,Questions

Arbor washers for table saws,bench grinders etc.I have been trying to source them in Aus but they don't seem to be available,unless I am using the incorrect name.Are they just a machined washer with a raised edge or can they just be machined flat and are they made from special hardness steel? Also is there a supplier for enclosed spindles?Or do we have to make do with pillow blocks? and where can threaded shafts be purchased from? And are they made from hardened steel?Can enclosed spindles be made from pipe with a bearing in each end or are they made to specific specs also?Lastly Optical linear Rail can an off the shelf Die be used?

Having a lathe [or inventiveness with a mill] arbor washers can have a raised edge. It's more a design enhancement than requirement. Becomes more with increase of diameter; manual lathes don't face perfectly flat. The relief insures fastener torque is applied to the periphery of the washer.

Selecting hardness might stem from two considerations. a) Horse power, RPM + balance. b) Room allowed for suitable washer. I'd feel confident with mild steel; faces very parallel, relieved driving side, a good proportional thickness to ID, gently tapered from fastener seat to perimeter, all thick enough to not deflect under fastening torque. My fingers depicting such a washer 3-odd inches in diameter could be relieved by 2/3 thirds. A large washer could be aluminum, faced with a conventional steel washer. Buying them would be easiest as a replacement part in desired size. When I run into nomenclature issues, I start online with an industrial supplier. You'll find Mcmaster-Carr absolute king of the hill. They catalog over a half million items, with suppliers of related stuff maybe another quarter million. I hate [and won't support] corporations needing surveys to feel competitive; Maccaro is PRIVATELY HELD! https://www.mcmaster.com/ They'll list most any part imaginable. And so informed, that reveals more sources. A particular online collection comes to mind IYKWIM; W=who lol. A lot of East Pacific buying also finds Bang good...Gear best and Alie expressly for that stuff. I find their pages too full of links to navigate smoothly and naming terminology not so universal. [At least one party is clumsy]. I guess that comes from limited use too.

Enclosed spindles might be off the shelf; but stocking that kind of variety sounds unlikely. I'd survey work here [HMT.net] of h7eh7e and Vyacheslav Nevolya; they have fine solutions about shaft building, including motor extensions.

Pipe intones a huge range of products, some isn't ideal shaft enclosure, but the form is. What you seek is tubing, benefiting from how its made.

Threaded shafts fall into same issue as ready made spindles. Metallic qualities such as straightness and hardness relate to intended load. There I'd venture bravely into https://www.engineeringtoolbox.com/ B-B-Best recon wormhole everrrr... Emphasis intentional.

Unless you possess incredible wealth and cursing vocabulary, interactions of a die and external diameter of linear rod are futile. The case hardening is deep deep deep. It can be turned off and single point threaded, even better is just drilling and tapping the end. Cross drilling's best initiated with a carbide end mill to produce a flat to center drill.

Ohh of course, what creation are you after? This invites any possible questions, an entire army of engineers/ modelers/ machinists/ fabricators await!