Milling. The milling machine provides a stationary, rotating cutter and the stock is shaped by moving the stock beneath the cutter. The cutter can have multiple teeth or cutting edges which removes chips of the material as the cutter rotates. These cutting edges are on the outside edges of the cutter, although some cutters have cutting edges across the entire face of the cutter. Milling is the primary means for obtaining an absolute flat surface and is useful for new castings. Using the milling head, one can use end mills (cutters) to cut into material or switching over to the drill chuck to perform precision drilling. Photo 17 shows a tail light stanchion held in a vise and a milling bit is used to cut a round groove into the base. Photos 18, 19 and 20 show the milling of a type of plastic material, called Delrin, to be used as a wire insulator. This shows that the machine is capable of either milling in small area or across a broader area. For performing this task, the cross table can be maneuvered in either the X or Y axis. Photo 21 show the importance of using small end mills for this Delrin plastic and Photo 22 shows the accessory collet set we used in all the milling processes demonstrated in this article.
Photo 17 — Photo shows an end mill removing some material on a tail light stanchion where a bolt passes by to keep the stanchion aligned in a bracket.
Photo 18 — An end mill is held in a collet and a piece of Delrin (Polyoxymethylene, also known as acetal) is fastened in the vise on the cross feed table and the Delrin is passed under the milling bit. All milling operations are performed manually with this Smithy unit, a disadvantage with this model.
Photo 19 — Shown is the Delrin material after all passes are made. The end milling bit was raised for the photo.
Photo 20 — The original wire suspension bracket with broken Bakelite insulators in shown at top. Below it are the final pieces of Delrin insulators fastened to a metal angle bracket. It is duplicated with some slight modification to the original.
Photo 21 — Set of double end mills come in both two and four flute types. Sizes are: 1/16, 3/32, 1/8, 5/32 and 3/16, all in a 3/16 shank. Sets like these often are on sale at tool suppliers like Travers Tool. Since they are small and may break, have spares on hand to complete your task and add spares to your next tool order.
Photo 22 — Shown is a general purpose collet set using a Morse Taper #3 adapter and 12 collets for sizes 1/16 to 1/2 inch.