[SonnyAgain]

John, will 2" do? I have Dieter Schmid's 2" tap and die set.... 2.5 threads per inch. I needed this size for repairing 2 vises, one each on 2 antique work tables. As jscseattle said, soaking the stock in oil makes cutting much easier. I soaked my stock in mineral oil for a week, then threaded them. For the nuts, drill your initial hole, then soak.... allows the oil to penetrate the area to be threaded. For the screw, soak the stock in a tube, I used a section of 3" pvc pipe.

I can likely make a set for you, if 2" will do. I have some 8' lengths of 4X4 air dried ash. I'd need some specs of your needs.
Sonny

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https://flic.kr/p/2jZoCHh https://flic.kr/p/2jYLbp2

 

[SonnyAgain]

I don't want to sell my set. I suppose the stock can be soaked in water, anything to soften the stock so it doesn't splinter when cutting. Only the part/surface needing threads would need to be "lubricated". I might test a piece in water. see how well it works and any affect on the stock, itself.

Yeah, long ago I had searched for large tap and die sets and found Dieter Schmid. I had tried hand carving threads and fail miserably. I saw one tutorial about soaking and the guy used mineral oil. My vises, the nuts, didn't need to be finished, so the oil was no issue.

Sonny

 

[SonnyAgain]

Further notes:
Not sure how well you can see it.... this is one of the broken nuts from one of my vises. The hole is offset, not centered on the block of wood. For your nut making, drill your hole in the center of your over-sized block, then trim your block as per any offset and outer dimensions you'd need. Also, in the previous pics, note the grain of wood relative to the direction of the hole.
https://flic.kr/p/2jZnPbx
I didn't/don't have a *drill bit large enough for drilling the initial hole... other than an adjustable brace bit, to drill the proper size initial hole.
https://flic.kr/p/2jYKkXB
Sonny

 

[SonnyAgain]

For my 4" cube nut blank, after drilling the initial hole, it took about 90 seconds to cut the threads. I didn't need a screw, but did a practice run on a 1.5' length and it took about 3 minutes to cut the threads, Check out this video.
Sonny

 

[SonnyAgain]

After some thought, I have one of these adjustable blacksmith's tapping tools, old tool from my grandfather's barn. I can't locate it at the moment, but I recall cleaning it up (rusty) last year. John, maybe find a right-sized one at a (rustic?) antique shop in your area. I had no problem using a crescent wrench, but you like 2 handles

Also, I have an ash nut blank soaking in water... will see how that threads, probably Friday - 3 days soaking.

Sonny