The broken drill chuck mentioned in Engraving pantograph was firmly stuck on the Morse taper to JT-33 adapter. With various means of applying pressure and hammer blows, nothing was found to free it. Consequently, a pair of wedges was needed to set it free.
The project began with a block of steel, 1/2" X 1 1/4" X 1 1/2". A hole was drilled in this block in the approximate center of a large face using the South Bend lathe. The hole was drilled up to 5/8". Then came the challenging part of this design, a hacksaw cut at an angle at right angles to the hole. Cutting through this much steel took about 2000 strokes of the saw. The photo below shows the steel after about 3/4 of the hacksawing was complete, the part flipped over, and the saw was aligned to complete the cut.
After cutting the block into the two wedges, both sporting the 5/8" hole, each wedge was mounted in the mill vise with the newly cut face up and approximately level. Each face was cleaned up in this fashion using a two insert face mill. With the part still mounted in the vise the slot from the thin edge of the wedge to the hole was made in two steps. First a hole was drilled up to 3/8", centered between the sides of the wedge and between the large hole and the thin edge of the wedge. A 1/4" end mill was used to open this hole to a slot 5/8" wide.
The various edges of the wedges were deburred with a deburring tool producing the wedges seen in the photo below.
The 5/8" opening was chosen to match the diameter of the thin neck of the adapter. The wedges were put in place with the disassembled chuck held in a vise. Two ball peen hammers were used to gently convince the wedges together freeing the adapter. This is shown in the two pictures below. The chuck went to the recycle bin and the adapter into the drawer of tailstock attachments for the South Bend lathe.
