I have several die heads Geometric, Hartness, and J&L tangent style all with pretty near full sets of chasers, I don't use them much, but sometimes they are worth setting up if much threading needs to be done, I bought a Warner & Swasey #5 turret lathe from the shop where I apprenticed, and got ALL the die heads in the place, except a 2 1/2 or 3" Landis tangent die head that I could not find, it was used on another turret lathe to thread
2 1/4" rebar right over the ribs in 3 passes, I think, they were welded into cages for bases for electric transmission towers.
The J&L heads I would like to sell along with the chasers and sharpening fixtures. They are too big for hobby use, guess I should put them on E Bay.