J4M MGK1312A

MGK1312A is named ×500 in Jinan No.4's current high-precision cylindrical-grinder page. The same page contains a shared 250/500 mm length block, 270/520 mm between-centres entries and paired dimensions/masses. That title/table inconsistency remains unresolved. Use the exact ×500 dimensional drawing before assigning supported length, footprint or lifting mass to an ordered build.

The current original table gives 100 mm centre height, Ø125 mm grinding diameter and 10 kg maximum workpiece mass. The wheel is Ø300 × 40 × Ø127 mm, with 35 m/s surface speed and a 2.2 kW wheel motor. These differ from the MK1312A wheel entries; the two references cannot be compared by adding the G or copying the MK package.

The manufacturer distinguishes forced-oil flat-V injection guides for wheel feed from oil-immersed flat-V guides for table movement. It describes a multi-oil-wedge large-taper hydrodynamic wheel-spindle bearing and a servo workhead, together with a hydraulic tailstock and online measurement. Freeze the exact selected control, gauge, support, dressing and coolant package, including what surfaces are measured and corrected.

The working-accuracy block is explicitly for national-standard test parts and lists roundness 0.0005 mm and cylindricity 0.003 mm. Its unusually low roughness entry requires clarification and is not adopted as an acceptance specification here. Trial the actual shaft material, hardness, stock allowance and support. Inspect released journal/face datum relationships and surface with the agreed method, and count loading, dressing, gauging and rejects in output. No unreviewed image or fabricated schematic is published.

Same listing
MK1312A