Perhaps I was not precise enough in my description. Yes, I did make the parallels myself. But absolutely no milling or grinding work was needed.
From McMaster Carr, a very good supplier (IMHO anyway) I purchased several lengths of
Flat Ground Stock
in various sizes. Then I walked over to my saw and cut several lengths from each of them: 1", 2", 4", and 6" long. I cut two of each length so I had matched pairs.
Their flat ground stock does not vary by much along a single piece. It is easily within 0.0001" in both of the shorter dimensions. The lengths are not matched and do not matter.
As I cut them, I marked the ones that came from the same pieces of stock with file notches at the intersection of a common side and an end. So I know which parallels came from the same length of stock. And, in the case of square stock, I know that the marks are on the SAME side: this is because the square ones did not match as well across the two pairs of sides.
I got a number of parallels. I got very high accuracy. I got a reasonable price. I did NOT invest much time: my saw could be started and ignored until the cut was finished. I did other things. And, as you wish, they are 100% made in the US. I did all the QC. I checked the stock's dimensions before using it. I checked them after cutting them. Accurate, quick and easy to make, reasonably priced; what more can I say.
The one thing mentioned above that I did not get was hardened parallels. I will be the only one using them and if, when I am 110 years old, they get a bit worn, I can always order some more flat ground stock. Oh, and I did not get a nice wood or plastic case. I just keep them in a couple of my plastic bin drawers.
Frankly I do not know how anybody can justify the price that Suburban Tools is asking. I am sure they put a lot of effort into them and can probably show you how they arrived at that price. But still, ..... All I can think of is GSA. And they probably get a contract price, not the list price.
I think making your own parallels is probably worthwhile, and I'd like to do it at some point. I'm still very green at this point, and time is an issue. I really need to tool up so I can hit the ground running. I've already got several projects to grind for class and others to make on the mill. There's just not enough time to make both my mill projects and other grinding projects wait while I fab my own parallels.
I'm definitely going to buy my first set of parallels, but it might be the last set I buy. Might not be a bad thing if I grind my own after that once I've built the chops, especially if the market for parallels remains as dismal as it seems to be right now.