My dad picked up a drill for me at a local estate sale. It’s a Milwaukee D-Handle drill Catalog Number 1000. Milwaukee still makes these drills with pretty much the same design. They’re meant for drilling large holes. The drill consists of a relatively large motor and a gear box. The gear box increase torque and decreases bit speed. The specified max no-load speed is ~600 RPM on these drills. The newer ones have a handle made of plastic and the body may be made out of magnesium alloy. The body and handle on this one is all aluminum though. I’m not sure how old it is but I’d guess it’s from the late 60s or the 70s. Either way it works when plugged in and the price was good. Besides, it has a lightning bolt on both sides. It must be good.
Here’s the info plate on the drill. The new ones say the motor will draw up to 7 amps but my dad swears the old ones, like these, were unstoppable tanks.
Of course I can’t just buy a used tool and leave it the way it is. I have to check it out and clean it up some. The first thing to do is remove the chuck. Milwaukee’s page had a manual for a similar model numbered drill with information on how to remove the chuck. It said, for non-reversible drills, to put the chuck key in the chuck and whack it with a hammer in the direction that the chuck rotates.
The recommended procedure worked well and I was able to unscrew the chuck. The more modern variants of these drills have the ability to put different attachments on the front of the drill such as a right angle attachment or angled extension. Unlike this drill, the newer drills have a hex shaped section of the spindle. The spindle is the part the chuck screws on to. A sleeve with an internal hex shape is slipped over the hex section of the spindle to use the attachments. Since mine is only threaded , I’m unable to use any attachments. Guess I’ll have to buy a more modern one too. Darn. In the picture below, you can see the three screws that hold the gear box together.
Once the three screws are removed the gear box can be separated to inspect the gears and grease. The grease inside looked good and I didn’t see any grease that was dried out or separated. Since it looked fine I decided not to replace it. If the grease had gone bad, then Milwaukee sells the appropriate grease to use for replacement. The back cover of the gear box is pressed onto the shaft of the motor so I decided to leave it alone.
Four screws hold on half of the handle. I removed it to check out the inside and the motor’s commutator. The commutator is the black part on the end of the motor. Note that the case is grounded via the green wire from the electrical cord. This way, if there is a short against the metal case, another ground will be found other than the operator.
I also removed and checked the brushes which ride on the commutator. They’re housed in the two cylinders normal to the commutator’s surface in the picture above. Both the brushes and the commutator showed little wear leading me to believe this drill has not seen a lot of use.
I put the gear box back together and blew the rest of the drill out carefully with compressed air. After this I turned my attention to the rusted chuck. Disassembly of the chuck requires pressing the outer sleeve off as described by Jacobs. My arbor press made quick work of this.
The core and outer sleeve of the chuck went into the electrolysis tube to clean them up and then everything was lightly wire brushed. All the parts were then oiled, grease applied inside the threaded split ring, and the chuck reassembled. Note how the jaws came out or see the linked Jacobs page above for help in identifying each jaw. Their order is important and if they don’t end up correct, they won’t line up correctly.
The Milwaukee D-Handle drills are sold with a handle that attaches perpendicularly to the body. If you’re drilling and everything is going fine, you don’t need the handle. But if the bit happens to catch on something, the drill will quickly twist out of your hand which could do damage to you and the drill. As this is undesirable, the drill is sold with another handle. On the models of these drills before the most recent version, the extra handle attached to the drill via a collar. My drill didn’t have the collar or handle. Luckily, I was able to find a collar on ebay for $4. The collar has a threaded 3/8-16 hole that is used to clamp the collar down. A regular bolt can be used in the threaded hole but might not be very comfortable on you hand. So, off I went to the lathe to drill a hole through a 1″ Poplar dowel I had left over. I couldn’t quite get to the other end of the dowel and had to drill it out from the opposite side as well.
Once I had a hole through the dowel I tapped a 10″ long carriage bolt into place. A spacer and washer were also used between the dowel and collar. Now you can turn the handle to loosen, reposition, and tighten the handle. A 10″ handle may be a little excessive but it’s better to have to much than to little. What’s nice about this handle compared to the newest ones is the collared handle. The collar allows the handle to be positioned to the best possible angle. The newest drills have a cheaper styled handle that just screws into the body from the looks of them on the web page.
Remember how I said the case is grounded to the green wire? Well, the green wire isn’t connected to the ground because the prong was broken off at some point. As I don’t want to be the ground someday, I cut the old plug off and replaced it with a new one.
Replacement was easily accomplished. One way to check that you’re not going to shock yourself is to use a DMM to check for continuity between all the prongs of the plug and the metal case. You should have continuity with the ground prong and case at all times. You don’t want continuity between the other two prongs and the case with and without the drill’s switch engaged. I wasn’t worried about shocking myself but thought I’d demo it. This technique would also be useful before firing up an old tool you just got for the first time.