Hinged Wade-Extruder block for M4 idler bolts, with a handle on the idler and a few fixes. Now updated, see below :) When I first printed Greg's Hinged Accessible extruder, I had to hack out the top captive nut holes that idler bolts went through since they were under-sized in one direction, then ended up accidentally over-sizing the holes with my multitool's chisel, so I used M4 nuts and bolts instead. (I wasn't even sure at the time if it was meant to be M3 or M4 fitting since the bolt holes were loose) I since realised that it's much easier to get enough idler pressure on the filament while using the same stiff springs that support my printbed, which barely fit in the area of a form-A M4 washer, while suggested pen springs on M3 bolts are nearly impossible to tighten enough and it's hard to find M3 bolts long enough in the first place. So, I've re-designed both the extruder and idler with holes that should be large enough to not need reaming for M4 fittings, while keeping over my double-option hot-end mounting slots from a design that I produced before finding the default STL-import options in SolidWorks that had prevented me editing things from STL before.Things fixed:The J-Head mounting body is based upon direct measurements of a Mk.IV hot-end using calipers. It fits better than any I've found yet.Update 1.1:Why does this idler handle have a hole in it? You tell me. Maybe you can loop a string through it for easier grabbing or attach something to it, I dunno.