This vintage Delta Rockwell DP-220 drill press was purchased by my great grandfather, and has been neglected in a dusty corner of my father’s shop for decades. Despite the lack of maintenance, the drill press has still performed its job admirably when infrequently needed for the odd-job or project. During the process of building and outfitting my home woodworking shop it quickly became evident that a drill press would improve the quality of my projects, and make life much easier around the shop. I was elated to learn that my dad would give me the old DP-220…as long as he could come over and use it whenever he needed. Deal! A little elbow grease to restore a family heirloom is much preferred compared to spending hundreds of dollars on a new drill press. Not to mention that these old machines manufactured in the U.S.A. are quite robust & well respected compared to their modern contemporaries which are mostly manufactured overseas and commonly include a number of cheaper…err less durable…components.
Luckily there is no shortage of information about these venerable machines on the internet. The Vintage Machinery website is a great repository for information about these old Delta machines in addition to equipment from many other manufacturers. A quick search of their DP-220 serial number database indicated that this particular unit was manufactured in Milwaukee, Wisconsin in 1948 on the heels of World War II. During my research I also came across Hammerscale Technologies, which is a small shop specializing in OEM & reproduction replacement parts for these old machines. They also offer full spindle rebuild services, and provide a runout measurement report for your spindle after the rebuild process.
The first step in the process was to take everything apart. Every component was disassembled, cleaned, and inspected for damage. I was surprised to find the original operating/repair manual tucked away in the bottom of the center column near the base. These are available online as well, but the 1947 print date on the manual confirmed my previously discovered manufacturing date. For the spindle, I decided to send it out to Gary at Hammerscale for the rebuild and bearing replacement service. He was able to turn it around in less than two weeks with a measured runout at the taper of only about 0.0015″. This is definitely precise enough for any work I’ll be doing with this drill press. The only other component that needed replaced was the DP-277 pulley spindle bearing. This is a specialized bearing for the upper pulley with an extended/machined inner race. All cast iron parts were stripped of their old Battleship Gray paint, and painstakingly attacked with an angle grinder to remove all surface rust. All the castings were still in great shape with no major damage or pitting. They were then cleaned and painted with a Krylon Metallic Gray spray paint. Rust removal gel was needed in addition to the angle grinder to speed up the process of rust removal for the main column, and a grinding wheel was used to remove rust buildup from the remaining bare metal components.
The vintage motor was still fully functional, and didn’t require significant disassembly or maintenance. I simply cleaned it up, put a fresh coat of flat black paint on the case, and used compressed air to blow out the decades-worth of dust build up from the interior windings. The capacitor housing and wiring box was disassembled to clean up the electrical contacts by removing rust with 600 grit sandpaper and cleaning with alcohol. The old motor switch was broken such that the machine simply turned on whenever it was plugged into a 120 VAC wall outlet. I found a 120 V 15 A switch for $6 before re-assembling the wiring box after removing rust and applying a fresh coat of paint.
One particularly difficult aspect of the rebuild was the Upper Spindle Return Spring. This spring is under a tremendous amount of tension when coiled to the diameter required to re-install into its housing. I fumbled around for a while and had several failed attempts at re-installing this by hand (with a pair of leather gloves). I was finally able to wrestle the spring into the housing with the help of a table vise and a pair of vise grips to secure the coiled spring during installation into the housing.