GP Drills

Yankee Drills


Tips from Old Millrat - James D. Thompson


Disassemble a Yankee Push Drill


I recently acquired a Yankee push drill which didn't want to function properly. I think it is a #41, but someone thought it proper to take the tool to a grinder and grind off the surface of the marked part of the barrel. I am going to presume that this was done to obliterate some owner's mark. I buffed up the damage a little so it wouldn't be quite so ugly.

I wanted to disassemble this beast to give it a good cleaning and oiling, but I could find no information on the internet that was useful. So I did what any good Galoot would do, I went at it in blissful ignorance. But I did take pictures, and I'll tell you how to do it. Here is a picture of the tool disassembled.

A few instructions are in order here. Notice at the very top of the handle that there is a cross pin. This pin passes through the twist screw. The pin has a taper on one end, and this is the end to tap on to drive the pin out. If you secure the handle in your vise it will be easier to drive the pin out. But do not drive it all the way out, just enough to release the screw.

Notice that there is a wooden dowel in the spring. Don't forget to put this back when you re-assemble it. I forgot and had to tear it down again. Also notice at the bottom of the picture that the chuck has a small screw into the side of the short shaft. You can see it better in this picture.

The shaft at the back of the chuck is a good tight press fit into the end of the barrel. To get it off, I placed the chuck in a soft jaw vise and held it there while I used a screwdriver for a punch to drive the barrel off of it. Put the screw back into the chuck now so it won't get lost.

So why does the smaller barrel turn when you push the drill? There are 2 dead trunions which fit into the grooves on the screw. If there is any grit on the screw the trunions will bind. So clean the screw perfectly clean before you re-assemble the tool.

When you put the chuck back it is necessary to align the 2 holes perfectly. If you are at all careless the holes will not line up, and you will have to remove the chuck via the vise again. I hate to admit it, but I had to do this. Remember, this is a press fit piece, and you can't align the holes if it didn't go together correctly.

Now that my ugly old push drill is nicely cleaned and lubed it works like a dream. Now you can clean yours, because there are instructions on the internet now.

Jim Thompson,
the old Millrat in Riverside, CA.
October, 2013


Sharpening Stones



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