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For Mill or Bench
Chuck Holder
© Frank Ford, 2004; Photos by FF

Any number of times I've wished I had a lathe chuck mounted on my bench to hold round things vertically. This weekend I decided to make a holder so I could simply use any of my lathe chucks. I figured it might come in handy for working on a item that needed both lathe and milling operations where I'd keep the part in the chuck so I could return it to the lathe for more work. So, I set about making a replica of the Hardinge style tapered spindle nose and a plate on which to mount it.

Looking around the shop, I located a nice scrap of 3/4" CRS. It had a bunch of holes drilled in various places, including a number of threaded holes in the edges. Just for a slightly neater appearance, I poured a bit of thin viscosity cyanoacrylate into the edge holes and drove screws into them, cutting them off flush. Most of the top holes got cut off when I trimmed the plate to size, leaving just two visible.

Clamping the plate in the mill vise, I squared it up.

And, flattened the bottom face that would contact the mill table when in use.

I drilled a pilot hole in the center and followed with a 33/64" drill.

A 1" reamer finished my hole nicely.

Using the Darex online Bolt Circle Solver I spotted, drilled and countersunk a pattern of five holes for 1/4-20 cap screws. Why five? I don't know - it just seemed attractive at the time. This was a mighty casual project, and I made up the rules as I went along.

Seems I can never find my little bottle of layout dye, so I'm always reaching for the Steinway Touchup Kit.

Using the point of my caliper as a scribe, I got neat little locating marks/

First a center drill to spot the hole, then a 33/32" drill to receive 1/2" clamping bolts.

A quick bevel around the edge, and my plate was done.

I had this big (for me) of 3" diameter CRS from which I'd make my new nose. Now, I know you're not supposed to part between centers, but nobody said I couldn't make a really deep groove.

Once I got the center down to about an inch or a bit less, I introduced the bar to Mr. Bandsaw. I just didn't want to stand there all day pushing on this thing, so grooving it saved me a lot of time and effort.

There wasn't a lot of grip to hold my piece back on the lathe, so I took it slow and easy as I faced off my cut end.

Off the lathe, I drilled a center hole in the opposite side, and pressed the faced end up tight into the chuck as I tightened it down. Then, I felt I had a good grip as I turned down the end to make a nice slop-free fit in my base plate's 1" hole click the following link.

Switching to a 1" collet, I stuck the turned end in, and center drilled the opposite end. I turned down the diameter of the nose section to the maximum diameter of my lathe's spindle nose, leaving a shoulder at the base for extra stability

Off the lathe, and simply gripped in the milling vise, I located the center, spotted and drilled the (#7) tap holes using the same pattern as the base. That's the Darex calculation I printed out, posted right on the mill.

Here's a little trick I use for hand tapping holes in the milling machine. It's one of those "works for me" kind of things. I use my lathe hand tap handle with its long shank, stick a 1/2" R8 collet on, and push it up into the quill. I don't use the draw bar at all, but simply let the collet ride up into the quill, keeping my tap nice and straight as I go.

OK, time to get "serious." This is the only operation that required any precision, so, in an uncharacteristic move, I took my time with the set up. Sparing no effort, I located the ball of my indicator precisely at center. Then, with about a hundred very light taps with my rawhide mallet as I slowly tightened the lathe compound, I was finally able to get it so there was virtually no needle movement as I ran the slide back and forth.

The setup time paid off (as it always does, for sure) and I was able to turn the nose section to a nice fit on the taper of this face plate. I had done all the turning with the center in place for extra support, of course.

And once I was happy with the fit, I went around to what would be the bottom side of the chuck holder, and took a very light skimming cut at the edge to make certain it would be true to my new taper, just in case.

I stuck the faceplate back on the taper, and screwed the pin down hard into the taper. That left me with a nice mark to locate the end of the slot I'd be milling.

With the tapered nose in my 5C spin index, I knew my setup was far from rigid, so I took impossibly light cuts with a 3/16" end mill to create the slot. I didn't take the trouble to try to figure out how I could cut the angled slot, so I just picked an approximate angle, clamped my spin index at that angle, and milled a really deep slot. At 3/16" the slot is considerably wider than the original, but I didn't think it would matter for a simple fixture as long as the chuck would go on and off appropriately tightly and easily.

I screwed the support to the plate.

Here's the final product. As you can see, I located the mounting holes so they'd line up with table slots.

And, the chuck pops on and off just as it does on the lathe.

Back to Machining Index

	Looking around the shop, I located a nice scrap of 3/4" CRS. It had a bunch of holes drilled in various places, including a number of threaded holes in the edges. Just for a slightly neater appearance, I poured a bit of thin viscosity cyanoacrylate into the edge holes and drove screws into them, cutting them off flush. Most of the top holes got cut off when I trimmed the plate to size, leaving just two visible.
	Clamping the plate in the mill vise, I squared it up.
	And, flattened the bottom face that would contact the mill table when in use.
	I drilled a pilot hole in the center and followed with a 33/64" drill.
	A 1" reamer finished my hole nicely.
	Using the Darex online Bolt Circle Solver I spotted, drilled and countersunk a pattern of five holes for 1/4-20 cap screws. Why five? I don't know - it just seemed attractive at the time. This was a mighty casual project, and I made up the rules as I went along.
	Seems I can never find my little bottle of layout dye, so I'm always reaching for the Steinway Touchup Kit.
	Using the point of my caliper as a scribe, I got neat little locating marks/
	First a center drill to spot the hole, then a 33/32" drill to receive 1/2" clamping bolts.
	A quick bevel around the edge, and my plate was done.
	I had this big (for me) of 3" diameter CRS from which I'd make my new nose. Now, I know you're not supposed to part between centers, but nobody said I couldn't make a really deep groove.
	Once I got the center down to about an inch or a bit less, I introduced the bar to Mr. Bandsaw. I just didn't want to stand there all day pushing on this thing, so grooving it saved me a lot of time and effort.
	There wasn't a lot of grip to hold my piece back on the lathe, so I took it slow and easy as I faced off my cut end.
	Off the lathe, I drilled a center hole in the opposite side, and pressed the faced end up tight into the chuck as I tightened it down. Then, I felt I had a good grip as I turned down the end to make a nice slop-free fit in my base plate's 1" hole click the following link.
	Switching to a 1" collet, I stuck the turned end in, and center drilled the opposite end. I turned down the diameter of the nose section to the maximum diameter of my lathe's spindle nose, leaving a shoulder at the base for extra stability
	Off the lathe, and simply gripped in the milling vise, I located the center, spotted and drilled the (#7) tap holes using the same pattern as the base. That's the Darex calculation I printed out, posted right on the mill.
	Here's a little trick I use for hand tapping holes in the milling machine. It's one of those "works for me" kind of things. I use my lathe hand tap handle with its long shank, stick a 1/2" R8 collet on, and push it up into the quill. I don't use the draw bar at all, but simply let the collet ride up into the quill, keeping my tap nice and straight as I go.
	OK, time to get "serious." This is the only operation that required any precision, so, in an uncharacteristic move, I took my time with the set up. Sparing no effort, I located the ball of my indicator precisely at center. Then, with about a hundred very light taps with my rawhide mallet as I slowly tightened the lathe compound, I was finally able to get it so there was virtually no needle movement as I ran the slide back and forth.
	The setup time paid off (as it always does, for sure) and I was able to turn the nose section to a nice fit on the taper of this face plate. I had done all the turning with the center in place for extra support, of course.
	And once I was happy with the fit, I went around to what would be the bottom side of the chuck holder, and took a very light skimming cut at the edge to make certain it would be true to my new taper, just in case.
	I stuck the faceplate back on the taper, and screwed the pin down hard into the taper. That left me with a nice mark to locate the end of the slot I'd be milling.
	With the tapered nose in my 5C spin index, I knew my setup was far from rigid, so I took impossibly light cuts with a 3/16" end mill to create the slot. I didn't take the trouble to try to figure out how I could cut the angled slot, so I just picked an approximate angle, clamped my spin index at that angle, and milled a really deep slot. At 3/16" the slot is considerably wider than the original, but I didn't think it would matter for a simple fixture as long as the chuck would go on and off appropriately tightly and easily.
	I screwed the support to the plate.
	Here's the final product. As you can see, I located the mounting holes so they'd line up with table slots.
	And, the chuck pops on and off just as it does on the lathe.