Traditional granite surface plates mostly adopt through‑hole bolts to fast‑install modules and tooling fixtures. Though easy to operate, this method tends to cause direct extrusion and uneven stress on the granite substrate. For granite surface plates with embedded thread inserts, metal threaded bushes are pre‑embedded into the granite base during manufacturing. Widely adopted for ultra‑precision inspection stations and linear‑motor platforms, it effectively solves various assembly pain points of ordinary through‑hole structures.
Granite features high hardness yet brittleness. Tapping threads directly into stone easily leads to thread stripping and cracking. Repeated disassembly and assembly may render holes completely unusable. Made of metal, embedded thread inserts bear all tension and torque instead of the granite body. It fundamentally avoids cracking and thread failure of stone holes, enables repeated disassembly of modules and fixtures, and greatly improves reusability of surface plates.
From the perspective of complete‑machine assembly, embedded threads allow flush‑mount design without protruding bolt heads. The whole tabletop stays smooth and continuous, free from interference on workpiece placement caused by raised bolts. During equipment integration, guide rails, grating brackets and positioning fixtures can connect directly with threaded holes. No extra adapter plates are required, which reduces cumulative assembly errors brought by intermediate parts and delivers authentic positioning accuracy. It is especially suitable for high‑demand stations such as semiconductor inspection and optical testing. 
Large‑size granite plates often require multi‑point locking for system integration. Inserts can be flexibly arranged per customer drawings for even force distribution. Compared with few‑point through‑hole compression, multi‑point embedded inserts disperse assembly stress and lower the risk of micro‑deformation induced by local stress concentration. The original flatness of plates can be well preserved, which is critical for Grade 00 and 000 ultra‑precision plates.
Technically, inserts are not simply pressed into stone. Multiple procedures including precision boring, positioning and solidification ensure tight combination between inserts and granite substrate to prevent loosening or falling‑out. All processes are finished in constant‑temperature, constant‑humidity and vibration‑isolated workshops. Inserts are embedded after stress relief of blanks to avoid position offset caused by later‑stage stone deformation. Apart from plate flatness, factory inspection also verifies locking strength and positional tolerance of inserts. All test instruments are traceable to metrology institutes and comply with DIN, ASME, GB and other international standards.
In practical projects, plates with embedded threads can directly match linear‑motor slides, AOI tooling and special fixtures for metrology laboratories and shorten on‑site commissioning cycles. While through‑hole solutions demand on‑site gaskets and modified connectors, embedded‑thread plates support direct assembly upon arrival and reduce on‑site machining work.
Note that embedded threads cannot resist damage from excessive violent tightening. Fastening shall follow standard torque values. Supported by complete manufacturing and metrological systems as well as sufficient blank aging process, UNPARALLELED granite surface plates with embedded threads balance substrate stability and assembly convenience and serve as reliable reference carriers for high‑end equipment integration.