By Roger Leete
This tool was made for my Grizzly G8689, but it can be adapted to almost any mill. Just choose the right sized socket for your particular drawbar. Note that I did not come up with this idea, but found it on the web. I made the parts based mostly on the materials at hand. Dimensions are mostly made up on the spot, and measurements were all made with a scale. In other words, this project requires no careful measurements or has any critical dimensions.
Socket
First step is to find a deep well socket that fits the drawbar. For my mill, that means 17mm. I bought sockets at Harbor Freight, but just about any cheap deep well socket will do. HF has them for about 2 bucks. As you can see from the pictures below, I cut about 1/2-inch off the drive end, simply parting it off at the line on the socket. (Some sockets have a different appearance, so roughly 2-3/8-inch long) This dimension is by no means critical. I was worried that the sockets may be hardened, but a standard HSS parting blade cut it cleanly and easily. This operation was done on a 7×12 mini lathe, so it’s not like you need an expensive machine to part off. When you break through to the square bore it will be an interrupted cut, so take it slow at that point, or finish with a hacksaw. Tip: get or make a carriage lock for your lathe. It makes parting so much easier.
Next operation was to bore out the square drive hole. Once again, this was done on the lathe. The square hole makes for an interrupted cut, so take it slow and easy until you get it round to avoid too much impact on the tool bit. Drilling first may be easier, to remove the bulk of the material. You want to bore it out enough for the inner filler piece, but leave enough wall thickness for strength. My bore is about 5/8-inch diameter, but this is not critical either. I purposely made the bore tapered slightly. I’ll explain why in the next step. Set your compound over a degree or two, and bore it out to size. The socket machining is done for now.
As purchased on the left, machined on the right
Next piece is the inner filler. I made mine out of brass for weight, and because that is what I had on hand. Steel would also work, but I’d not recommend aluminum as you want more mass. This piece is slightly tapered the same as the bore. The reason for this is to have it jam up into the socket to facilitate tightening of the hammer head. Once turned to size, drill and tap for the hammer head screw. I used 3/8-16, but 1/4-20 would work just as well. You want enough thread to hold securely, but if you go too deep, you’ll be tapping into the side of the screw when you make the handle. Using a hacksaw, cut a screwdriver slot in the opposite end. Continue reading Wrench/Hammer Combination Tool for Mini Mill
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