Automatic Planer Knife Sharpening Machine Electromagnetic Chuck 1-4 Knives At Once

Replace one blunt knife in a planer head and the head stops cutting as a set. One knife sits proud, takes the cut and wears first, and the finish shows it. That is why planer knives have to be ground together rather than one at a time — and it is the reason a workshop keeps sending whole sets out.

The MJ-256 is a water-trough knife grinder with an electromagnetic chuck. The chuck face holds between 1 and 4 knives side by side, so a whole set goes onto the bed together and comes off having been ground to the same depth in a single pass. The chuck is switched on and off from a rotary switch on the machine bed, rated 20 A.

The knives are ground wet: a water trough under the work bed means the wheel runs through it, so the edge comes off cool rather than burnt and soft. Feed is automatic, with the head carried on a profile linear rail along the machine, so the pass runs at a steady rate instead of at whatever speed the operator pushes.

The machine is built for carbide and HSS planer knives. Grinding length runs 0 to 700 mm and a 1.5 kW motor turns the spindle at 2840 r/min. It runs on 380 V, is built to GB12557-2000, and stands 1100 * 500 * 1300 mm with the work bed at waist height.

The electromagnetic chuck is what makes this machine different: it is how a set of planer knives gets ground as a set.

• Electromagnetic chuck — holds the knives on the bed without clamps standing in the way of the wheel.
• 1 – 4 knives in one setup — a full planer head set goes on together and is ground to the same depth in one pass.
• For carbide and HSS planer knives — woodworking alloy and high-speed steel knives both come off the same bed.
• Grinding length 0 – 700 mm — covers the knife lengths used on planers and moulders.
• Water trough under the work bed — the wheel grinds wet, so the edge does not burn and does not lose its hardness.
• Automatic feed — the head is driven along the machine at a steady rate rather than pushed by hand.
• Profile linear rail — the head carriage runs on a profile rail, which is what keeps the pass straight.
• 1.5 kW motor — spindle power for a full pass across a set of knives.
• 2840 r/min spindle speed — a controlled wheel speed for an even bevel.
• 380 V supply — confirmed against your supply before the order is placed.
• Built to GB12557-2000 — the machine is built to a published Chinese machinery standard.
• 1100 * 500 * 1300 mm — a compact footprint for a 700 mm grinding length.

For a joinery or furniture shop running a planer or moulder, the MJ-256 fixes the problem that sends knives out in the first place — the set.

• The set comes off matched. An electromagnetic chuck holds 1–4 knives at once, so every knife in the head is ground to the same depth in one pass. That is what stops one knife doing all the cutting.
• Carbide and HSS on the same bed. The machine is specified for alloy and high-speed steel planer knives, so a shop running both does not need two machines.
• Wet grinding keeps the hardness. A water trough under the work bed means the edge is not burnt, so a freshly ground planer knife holds its edge instead of going soft in the first shift.
• An even bevel along the whole knife. Automatic feed on a profile linear rail drives the head at a steady rate, so the edge is the same depth end to end.
• A set back on the machine the same day. Grinding in-house means the planer is not standing while a set of knives is in transit.
• Built to a published standard. GB12557-2000 — the machine is built to a standard, not to what the workshop felt like on the day.

Carbide and HSS planer knives used in woodworking — the alloy and high-speed steel knives that go in a planer or moulder head.

With an electromagnetic chuck built into the work bed. The chuck is switched on and off from a rotary switch on the bed, rated 20 A.

1 to 4, laid side by side on the chuck. Grinding a set together is what keeps the knives matched in the head.

Because grinding a knife dry burns the edge, and a burnt edge has lost its hardness. The trough keeps the contact point wet, so the edge comes off cool.

Yes. The head is driven along a profile linear rail at a steady rate, which is what keeps the bevel even along the whole knife.

0 to 700 mm.

2840 r/min on a 1.5 kW motor.

380 V, confirmed against your supply before the order is placed.

GB12557-2000.

MOQ is 1 set, lead time is 5–8 working days, payment is by T/T, and the machine ships in an export-standard plywood case.