J4M MK1312A

MK1312A is currently described by Jinan No.4 as the ×250/500 CNC cylindrical grinder. Its original model page gives 100 mm centre height, Ø125 mm maximum grinding diameter, a 10 kg workpiece limit, 270/520 mm between centres and 250/500 mm grinding lengths. Distinguish the two length builds on the actual dimensional drawing; do not combine a longer shaft with the shorter footprint or support arrangement.

The listed wheel is Ø400 × 50 × Ø203 mm, with 45 m/s surface speed and a 3 kW wheel motor. The manufacturer describes AC-servo wheel/table feed through ball screws, oil-immersed flat-V guides and a hydrodynamic wheel-spindle bearing with independent oil supply. The workhead uses variable-frequency speed regulation; a hydraulic tailstock sleeve is described. Match the shaft drive, support and wheel approach to each journal and shoulder.

The page lists a two- or three-axis CNC package and an online measuring instrument for a closed-loop grinding cycle. Specify the actual control and gauge range, the surfaces measured and the correction sequence. A gauge entry does not establish automated inspection of every shoulder, face or datum. Confirm dressing, wheel and coolant/filtering as a complete selected package.

Working accuracy is explicitly stated for national-standard grinding test parts: roundness 0.0015 mm, cylindricity 0.005 mm and Ra0.32 μm surface roughness. These are conditional catalogue entries, not a promise for your shaft. Trial the intended material, hardness, allowance, centres/support and thermal state. Inspect released journal geometry and datum relationships; include loading, dressing, measurement and rejects in accepted output. No unreviewed image or schematic is added.

Same listing
MGK1312A