This video documents an urgent, high-priority machining job for the local Pensacola airport involving the modification of a critical shaft used in their luggage handling system. The main tasks included precision cutting a 1 7/16" diameter shaft to 60 3/4" length, drilling and tapping one end for 3/8-16 threads, and milling a continuous keyway down the entire length. The machinist utilizes a KBC mill setup with two vices and a large parallel for tramming, followed by using the existing keyway geometry to align the shaft for milling the new keyway in two sections. A secondary task involves single-point threading two 3/8" round stock pins. The project showcases traditional manual machining techniques under a tight deadline, successfully completing the necessary modifications for the inoperable airport equipment.
Hot Job in the Shop: Machining a Critical Airport Shaft
0:17 Urgent Project Scope: The machinist takes on a "hot job" from the local airport to modify a critical shaft (1 7/16" diameter) needed for inoperable luggage machinery. The job also requires creating two small threaded pins (3/8" stock, 2 3/8" long, 3/8-16 threads).
1:51 Milling Machine Setup: The machinist sets up two vices on the KBC mill, using a 36-inch parallel to ensure both vices are precisely trammed in tandem.
5:21 Lathe Work (Cutting and Setup): The shaft is cut to the required 60 3/4" length. The machinist chooses to use the 4-jaw chuck (instead of the faster 3-jaw) because the 4-jaw is needed for another job immediately following this one.
10:50 Drilling and Tapping: The newly cut end of the shaft is drilled and tapped (3/8-16 threads) using the lathe, taking care to use a slow RPM (250) due to the shaft's unsupported length.
13:32 Tapping Technique: A spiral fluted tap is used to pull chips out, followed by a four-flute plug tap to run the threads deeper into the hole.
16:34 Keyway Alignment: The shaft is transferred to the mill for keyway cutting. Precision alignment is achieved by placing a high-speed steel tool bit into the existing keyway and clamping a parallel onto it, which is then indicated parallel to the machine's travel.
18:58 Keyway Milling: A 1/2-inch, 2-flute high-speed steel end mill is used. The depth is matched to the existing keyway depth (~0.188"). Due to the shaft's length (60 3/4") exceeding the mill's travel (31"), the keyway must be milled in two separate passes.
22:30 Manual Machining Feel: The operator emphasizes the importance of "listening and feeling" the manual mill to adjust the feed rate and find the sweet spot for the cutting process.
33:01 Coolant System: The Noga Mini-Cool mist system is used with Trim Mist lubrication, noting that while effective, the tip often clogs and requires cleaning.
35:52 Quality Check: After milling, the keyway width is checked against a 0.374" gauge block stack-up and the provided key to ensure a proper fit.
36:30 Threading Pins: The focus shifts to the two short pieces of 3/8" stock, which are single-point threaded on the lathe for 5/8" back with 3/8-16 threads.
46:02 Project Completion: The job is successfully completed and ready for the airport personnel to pick up, meeting the urgent turnaround required for the critical equipment.