Don't forget that McMaster Carr sell metal in all kinds, in many sizes. Study the online catalog.

I have bought large dowel rounds cut by them at 1". Accurately, they stock them. Huge Chicago area warehouse.

At my old shop i could exactly specify big sheets of steel already cut to almost any size. Like !' ground flat 36x72" and delivered to my corner. Outside vender. Which became our welding table, after we welded a base for it.

We also had a metal shear that could cut 1/4" 4X8 ft sheets into tiny pieces or in 1/2 with a bang.

Loading that monster with a full sheet was a one man job with power hoist and one clamp.

Gotta know how and I never was a strong man, finesse did it.