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Xincheng Precision | Selection and Maintenance of Pull Studs


Pull stud is the tension part between the principal spindle of the boring milling CNC machine tool and the tool holder. It is also called pull head, connecting pull head, thread pull head, tool holder pull head, tool holder pull stud, tool holder joint, fastening pull stud and tool holder tensioner, etc. Due to its small volume and low value, its importance in work is easily neglected by people. To better develop the role of the lathe, it is necessary to have a understanding about the pull stud and lathe tension mechanism. 

Pull stud stand and its combination: pull stud is the spare part fixed at the tail end of various tool holders through thread. The tension mechanism inside the principle spindle of the lathe tensions the tool holder in the principal spindle by use of it. The tensioning is maintained by replying on a group of springs. After tension is realized, the prolapse of tool holder and tool from the high-speed rotary principal shaft can be avoided sufficiently.

Pull stud is designed according to the standards of tool holder and related part of the lather. Due to the various standards for the tool holder, the lather tension mechanism also differs. Therefore, the united standards can not be formed for the pull studs. Sometimes, the two ends of the pull studs live up to certain standard (like ANSI, DIN, ISO or JMTBA). However, sometimes, the mixture form (the thread part is adapted to the tool holder part of ISO standard while the pull stud head is also adapted to the lather of ANSI. In this case, such mixture combination can bring about a lot of different pull studs) also exist. In case of inappropriate selection of pull studs, the accident will be caused when using the tool holder after it is installed in the tool holder. 

Selection of pull stud: facing various pull studs, how to find out the specification and type you need. It is better to select the pull studs according to the instruction of the lather. The drawing or type of the pull stud will be given out in the instructions of lather by most lather manufacturer. Additionally, the determination can be made after measuring the pull studs for the lather. Most pull studs are of 10-12 dimensions. It is necessary to provide the details to the supplier in case of ordering. However, the attentions should be especially paid to main three parts: namely the angle of pull stud, the distance from the base level to this angle and the thread type. These three dimensions are easily measured. If a national lather(Actually, the taper hole of the principal spindle is British system dimension, it is just labeled by changing it into the metric unit) and a batch of of tool holders of British system taper are bought for a workshop. As for the pull studs, the thread is labeled with America system(adapted to the tool holder), the metric system shall be used for other dimensions and adapted to tension mechanism of lathe.