T.J. Davies Co. Inc., a manufacturer of retention knobs, can make custom machine components for older machines where parts are hard to obtain or are no longer available. Their engineering staff can work from detailed drawings or reverse engineer from supplied parts, using a digital optical comparator to accurately measure dimensions. Parts made of American-made 8620 alloy steel which has a high tensile strength to withstand strong centrifugal force, high load force, high feed rate, and difficult to machine material. All dimensions of retention knobs can be customized, including length, diameter, thickness of collars, dimensions between collar and knob end, thread size, and more. Additionally, customers can specify a coolant hole, taper style, and whether O-rings are required. Custom made retention knobs are sized to fit the machine tool and spindle or toolholder to maximize the toolholders performance and cutting tool life and extend the life of existing machine tool assets. "Typically, we have 2 – 3 custom jobs going at any one time," says TJ Davies President Sherry Davies. "Customers like our short lead-times, so we get a lot of custom work. They also appreciate how our quality keeps older equipment productive and profitable." All knobs are machined in-house with single point threading to Imperial (Class 2A UNC) or Metric (Class G6) standards. After threading is completed, each component is heat treated to 58-62 HRC then treated with hot black oxide to military specifications for protection against corrosion. Each retention knob is magnetic particle tested and then pull tested to 2.5x the pulling force of the drawbar it is designed for. The use of 8620 alloy ensures the components will work harden over time, rather than becoming brittle as is the case with the use 9310 alloy steel. Single-point threading ensures the threads are balanced (lead-in/lead-out at 180℃) which is very difficult to achieve when rolling threads. Full depth is also attained for each thread. All machining is done with a single set-up, to achieve Концентричност . Всеки компонент се обработва с топлинна дълбочина 0 . 020 до 0.030. Не се прилага въглехидрати за охлаждаща зала, за да се гарантира, че няма подхранване . основна твърдост на 40HRC е стандартно .} vertention knobfe a precision finish of 32 RMA micro or better, ISO grade 6N. Certifications are maintained for each step and each batch to ensure traceability and quality control. Overtightening can overly stress the retention knob, leading to premature failure, and can cause toolholder swelling and expansion. TJ Davies provides recommended torque guidelines with each retention Коноп, изпратен . Препоръките за изграждане на машини, винаги трябва да се използват, когато са налични. Предлагат се гнезда за правилното инсталиране на задържане на копчета, индивидуално или като пълен набор от 4. Всички гнезда и задържащи копчета се произвеждат, за да бъдат точни спецификации, които надвишават стандартите на индустрията и са достъпни чрез дистрибуторите в цялата страна.