Well, just voided my warranty on my Jacobs drill chuck
.
Just kidding.
I have wanted to do this for a long time. And today I had problems with my straight shank chuck and just couldn't resolve it quickly.
Short story: I cut the tang off the MT2 taper, and threaded the end with 3/8 - 16. Much more solid, and no more problem with the old chuck.
Long story: I was testing notching 1" conduit for my lathe brake foot bar. I have Lenox , Blu Mol, and Milwaukee hole saws. I like the Lenox the best due to the aggressive teeth, but was afraid it wasn't going to work on the conduit. I thought I might need finer teeth. So I put the mill in low (mistake #1) And tried notching the end of the conduit. It kept grabbing, and stalling the belts on the mill. The motor continued on, mainly because the motor in low is real small. Finally it broke the chuck off the J33 taper . The previous owner of the chuck didn't fix the problem correctly, they used a punch to set the taper and chuck. 3 around the edge of the chuck. It's preventing the chuck from seating. So, no time to deal with it now, I tried, but it's going to require a lot more work. So time to take one of my super chucks and cut the tang off. I have wanted to do this for a long time. There are no Mt2 taper to J3 (14n uses J3) with a draw bar connection. My Clausing mill self ejects tapers because it has a cap on top of the spindle that draw bar that pushes on. That means having to remove the cap and 2 set screws each time to use a regular tanged drill chuck.
I don't want to do that, and no doubt a draw bar makes it a more solid connection. I thought it was going to be case hardened but it was easy to cut with a HSS parting blade, and then drilled and tapped for the draw bar. Tapping was hard. I was worried that I would break the tap. But just lots of backing out and cleaning.
Done: back to notching. This time brought the speed to the lowest speed in high. And successfully notched the end. Now that I know it will work, I'll pick up another Lenox in 1.125 and I'll grind the extra 60 thou needed, or file it with a coarse rat tail file.
Finally I get to use my 14n in the mill, instead of just in the lathe. I'll make another ejector button for the lathe tailstock if I want to use it there. Sometimes I load up all the chucks with different drill bits for a job, and switch chucks rather than change bits in a chuck.