FOR IMMEDIATE RELEASE   T. J. Davies Manufactures the Industry’s Widest Range of Retention Knobs Mantua, OH – With over 500 styles available, T. J. Davies Co., Inc., manufactures the industry’s broadest line of retention knobs. Each is manufactured from American-made 8620 alloy steel that is then machined in-house with single-point threading to Imperial (Class 2A UNC) or Metric …