Jaw Plates: Fixed and Swing Plates in Manganese Steel

Two plates, one crushing chamber

A jaw crusher's chamber is formed by the fixed jaw plate, bolted to the frame, and the swing jaw plate, carried on the moving pitman. Rock is nipped between them at the top of the stroke and works down as the jaw opens and closes. The plates look like simple castings; their tooth profile is not simple at all. Teeth must grip the feed so it crushes instead of sliding, and the tooth pitch and height set the chamber's effective geometry as surely as the crusher's setting does. We supply plates in profiles for coarse primary rock, for slabby feed and for recycled material, and the profile conversation is part of every quotation — not an upsell.

Manganese grades for the duty

Jaw plates are manganese steel castings, and grade follows the same logic as cone crusher liners: the steel must work-harden under the impact your feed delivers. Very hard, abrasive shot rock and softer, slabby recycled concrete are opposite ends of the duty range, and a plate grade that excels at one can disappoint at the other — wearing fast where it should harden, or cracking where impact concentrates. Tell us the feed, the crusher model and the life (in hours or tonnes) your current plates achieve. That is enough for us to confirm the grade and profile we would cast, and to flag honestly if your current life is already at what the duty allows.

When to change plates

Plates are commonly run too long because the crusher still crushes. The economic signals arrive earlier: tooth height visibly flattened in the chamber's working zone, throughput falling at the same setting, discharge gradation coarsening, and — the expensive one — wear breaking through toward the plate's back, after which the pitman or frame behind it starts wearing too. Rotating or flipping plates where the design allows it evens wear, but a plate changed on time is always cheaper than a pitman repair. Our article on jaw crusher parts and their functions covers plate wear in the context of the whole machine.

Supply and fitment

Plates for our own jaw crushers are standard catalogue lines; replacement plates for other machines are matched to the original part number or a dimension drawing, and every plate is identified against its part number or dimension drawing before dispatch. Plates are usually ordered as a set (fixed + swing), but the minimum order is 1 piece, confirmed with your quotation — a single swing plate to test profile and grade in your feed is a sensible, common first order. Lead time is confirmed per quotation (typically within 15 workdays in peak season for common lines). Shipment FOB, EXW, CIF or FCA; payment T/T or L/C. Certificates available upon request.

Parts	Fixed jaw plate, swing (movable) jaw plate
Material	Manganese steel, grade matched to duty
Profiles	Coarse primary, slabby feed, recycling duties
Minimum order	1 piece, confirmed with your quotation

Reading a removed jaw plate

A worn jaw plate is a report on the whole primary station, if it is read before it is scrapped. Teeth flattened evenly across the working zone describe a plate that lived its design life — reorder with confidence. Teeth worn hard at the bottom and fresh at the top suggest the chamber is passing feed too small for its profile, crushing only in the lower zone. One-sided wear points at feed presentation or a chamber alignment question. And cracking — especially early cracking — separates into two stories: tramp iron events, which the toggle plate should have absorbed, or a grade too brittle for the impact the feed delivers. Photograph both plates at removal, note the tonnes and the feed, and send the evidence with the enquiry. Plate supply from this programme is specified from exactly that evidence, which is how a replacement set quietly outlasts the one it replaced.