Necessity (and personal preference) are the mother of invention, right?These ends are installed on my MendelMax, with over a dozen print-hours on them and I am extremely happy with the Acme rods and these ends. I hope others may, also. I have them listed as "a work in progress", but honestly do not forsee making further modifications.I desired to move from regular threaded rod to Acme rod and found inexpensive 3/8-12 oil-finish Acme rod at Enco. I then began looking at available X-end designs... and found Aleph Object's variation of their great clamp-style ends : http://www.thingiverse.com/thing:14812Close, but not quite exactly what I wanted.Features of these ends are double-nut with spring column for anti-lash and head-crash protection with integrated spring "perch" or "seat", fully-enclosed double LM8UU bearing column, "improved" x-rod clamping area, and an integrated nut-trap and screw for z-endstop mech switch triggering.I am not an OpenSCAD designer, so only .STL files are available. All files were run through NetFabb, verified and printed.Print (1X) each : AO-style_X-motor-end_3-8acme_lm8uu_v3 AO-style_X-idler-end_3-8acme_lm8uu_v3 AO-style_X-motor-end-clamp_3-8acme_lm8uu_v2 AO-style_X-idler-end-clamp_3-8acme_lm8uu_v2Print (2X) : 8acme_nut_spring-guide&bearing_separatorHardware required : (8) M3x16 screws (4-each end) (1) M3x35 screw (z-endstop adjuster) (9) M3 hex nuts (10) M3 washers (4) "Heavy" acme hex nuts (11/16" across flats) (2) 1-1/2", .041 wire, .688 dia springs (.038 or .047 wire diameter, if you prefer)Assembly is pretty straight-forward. (4) M3x16 screws, washers and nuts clamp each end upper and lower pieces together on your x-rods. If you choose to implement the z-endstop adjustment screw, remember to insert an M3 nut in the nut-trap on the underside of the motor-end upper piece. Both ends have the lower spring "seat" integrated (it's just a small ridge at the bottom around the Acme rod hole), and the upper printed "seat" is not absolutely rquired, but if you use it, make sure to put it on between the spring and upper hex nut. The LM8UU bearing column is the "standard" height of Prusa-style ends. The bearing separator is a simple cylinder that needs to be inserted between your bearings. It is designed a little long! You will need to file or sand it for a nice, tight fit when you clamp the ends. Or, just re-draw and print one to your exact size need.(Apologies for the fuzzy phone pics of these installed... I will upload better...)