Custom Carbon Steel Grip Plug for Aerospace Application

Carbon Steel Grip Plug

Carbon Steel Grip Plug

This featured grip plug is a critical aerospace part and is composed of 4140 stainless steel that was heat treated to 32-38 HRC. To manufacture the insert, a variety of CNC Swiss Turning processes were applied. Using a SR-32J Star Swiss type lathe with live tooling, we turned each side and turned the start of the lead thread to a chamfer of .06 x .45 degree with the M14 x 2.0 for the major diameter and pitch diameter, and with a thread relief having 2 radii of .060″. Next, using the machine’s y-axis capability with live tooling, we milled two .670″ wrench flats into the stem. Throughout the machining process we maintained tight tolerances of +.001″/-.005″, with features on a common axis to be GD&T run-out of .010″ max. To conduct inspection we relied on an OGP touch probe and a vision system CMM, as well as micrometers, a custom thread gage, a drop gage, and a digital optical comparator.

The final Grip Plug featured .875″ round bar stock, with a .786″ outside diameter and a thread relief diameter of .450″. We then labeled each carton with part and lot numbers, as well as the quantity. Packaging was limited to 50 parts per box, in accordance with aerospace bag and tag requirements. Included in each order was a raw material certification, complete with chemical and mechanical properties, and quality control verification. The project took 4 to 6 weeks to complete, and was then shipped to our PMA client for use in the aerospace industry.

Specifications for the Carbon Steel Grip Plug

Capabilities Applied/Processes Swiss Machining
Opposite ends of the same part can be machined simultaneously.
Equipment Used to Manufacture Part Star SR-32J Swiss CNC Lathe w/ Live tooling
OGP Touch Probe and Vision System CMM
Overall Part Dimensions .875″ Round Bar Stock
O.D .786″
.450″ thread relief.
Tightest Tolerances +001″/-.005″
Features on a common axis to be GD&T run-out of .010″ max
Material Used 4140 Stainless Steel
Max Material Finish 63 RMS
Typical Machining Operations CNC Machining:
Set up On Lathe
Turn Side 1
Turn Side 2:  start of the lead thread to a chamfer of .06 x .45 degree with the M14 x 2.0 for the major diameter and pitch diameter, with a thread relief having 2 radius of .060″.Thread relief having 2 radii of .060″Mill wrench flats: Two .670″ wrench flats centered 180 DegreesInspection:
Inspected using:
Custom Thread Gage
Drop Gage
Digital Optical Comparator

Packaged to GMMCO Standards

Paperwork Includes:
Raw Material Certification w/ Chemical & Mechanical Properties
All paper work is Stamped w. QC Inspector Stamp
Packaging Slip

50 Parts Max. Per Box
40 Lbs Max. Per Box
Box Size 12″x10″x6″

Each carton To be Labeled w/ Part Number, Lot Number, and Quantity

Estimated Part Weight ¼ lbs
Industry for Use Aerospace
Delivery Time 4-6 Weeks
Standards Met Customer supplied print, 2D Auto CAD Drawing
Product Name Custom Grip Plug
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