Inquiry (采购产品): General Information - Facility Tour To Whom It may Concern, I was provided your company as a significant manufacturer of “drilled” head socket head cap screws by a number of screw suppliers. My company represents a Navy/nuclear program utilizing drilled, socket head cap screws, both as NAS1351/1352 spec’d product and as product manufactured to a Navy specification control drawings (altered-item NAS screws to add a deformable pellet locking device) that has a recurring issue with "stripping out" screw heads during installation (socket rounds-out prior to full installation torque being reached.) The screws are low-volume, "aerospace/aircraft" quality requirements and are primarily .250” and .190” sizes. This issue, while not occurring at an alarming rate, presents a significant problem because we are required to initiate a documented "reject" for the screws due to their failure and our Program and Company quality requirements direct that we must conduct a formal investigation, determination of cause and directed corrective action to address the issue. It appears the problem that we are wrestling with is that the ASME B18.3 Standard is "silent" on the allowances for finishing the edges/corners of wire holes within the screw socket . It appears that the much of the "industry" is performing the "required" finishing operations (B18.3 does indicate that for aircraft-quality screws that there can be burrs, chips or slivers . . .) by using a rotary burring tool and chamfering the holes within the screw socket by hand. Unfortunately, any chamfering reduces the socket torque bearing area and as a result the screw heads are "stripping out" during installation, prior to reaching their required installation torque. I appears that I will be in Los Angeles during the week of Dec 12 and would like the opportunity to tour your facility and discuss this issue and how it may be controlled by American Drilling Co. This issue may require that we re-source or otherwise specify the screw manufacturer or process supplier performing the drilling/deburring of the screw heads to adequately control the quality of the product that we are receiving. I look forward to hearing from you. Thank you for your time and consideration. **** Hidden Message ***** Randy Mathews 4747 Harrison Ave ROCKFORD, IL 61125 USA Company: Hamilton Sundstrand Corp Phone: 815.394.2011 E-mail: randy.mathews@hs.utc.com **** Hidden Message ***** randy.mathews@hs.utc.com
