T.J. Davies stocks a broad line of retention knobs for same day shipping.
"Manufactured from American-made 8620 alloy steel that is then machined in-house with single point threading to Imperial (Class 2A UNC) or Metric (Class G6), these components work harden over time, providing a long service life," said a company spokesperson.
After threading is completed, each component is heat treated to 58-62 HRC to a depth of .020 to .030, 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 2.5 times the pulling force of the drawbar for which it is designed. With over 500 styles available, T.J. Davies Co., Inc., manufactures a broad line of retention knobs; the most popular styles are inventoried for immediate availability for orders received by 3 PM EST.
In addition to the 500 plus styles available, T.J. Davies has an in-house engineer who can make custom knobs for older machines that are no longer made.
"The use of U.S.-made 8620 alloy steel helps ensure that the components will work harden over time, rather than becoming brittle as is the case with the use of 9310 alloy steel," said the spokesperson. "Single point threading ensures that 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. Because all machining is done with a single set-up, concentricity is achieved."
Each component is heat treated to a case depth of .020 to .030. No carb is applied to coolant through hole to ensure there is no shrinkage. Core hardness of 40HRC is standard. All retention knob surfaces (not just mating surfaces) have 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. T.J. Davies provides recommended torque guidelines with each retention knob shipped. Machine builder recommendations should always be used when available.
For more information contact:
T.J. Davies Co., Inc.
11823 Ohio Route 44
Mantua, OH 44255
440-248-5510
sales@tjdavies.com
www.tjdavies.com