How Would You Make This Part.

banned for 1.5 months for suggesting someone buy it, particularly when they ask for assistance with how to make it.
 
I appreciate all the suggestions so far. Keep them coming.

For clarification this project is not for me or of my own design. I mentor and train students on the lathe for the high school robotics team. They have a PM-1127 lathe with a non-standard bolt on spindle. I built a 5C collet closer for them a few years ago but since the machine is a variable speed belt drive they need a hand wheel on the spindle to tighten and loosen parts in the collets.

We looked for an off the shelf solution we could modify but anything close to what they want and in that size would be expensive and still require modification. They are requiring the wheel to be solid and smooth for safety reasons. The aluminum we get for free from sponsors and I am more than happy to donate my time.

I briefly looked at the ball turner concept but because of the 8" diameter of the wheel I am not sure there is enough clearance between the cross slide and the part to make that work, plus how do you get to the area inside the recess. I may give this some more thought but I'm not sure I want to make a ball turner tool right now either.

I don't quite have enough Y travel on the CNC mill to make that work.

woodchuckers idea of a reduced width form tool is intriguing and may be worth considering.
 
I made a form tool to cut the hemi shape of my model engine head. The depression is only ~0.95 diameter & relatively shallow. It seemed like a good idea but in reality was slow sledding. Cutting force was kind of high & required slow rpm to avert tool chatter. Your corner rounding fillet shape would be a big bejesus hunk of HSS & even more tool edge exposed as the shape progressed.

I subsequently made a simple rotating radius cutter thingy & it was soooo much easier traversing the cut with lighter depth of cut. I still think if you made parting like cuts to the spherical shape using a simple X-Y table & blended the ridges with a file you would have the job done before you ground the profile cutter.

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I made my hand wheel out of 1/2 inch aluminum plate counter bored for the shaft adapter. Works fine.DSC_7 future handwheel.JPG DSC_9 assembled drawbar.JPG
 
Maybe this better illustrates what I'm getting at. Pick some convenient reference point & step-over increment. Generate the coordinates of the ball shape just using dimensions picked off the intercepts. Now mount up something like a parting tool & cut in to whatever depth is specified by the ordinates. This leaves a jogged profile. Blue the entire shape (leaving witness color in all the valleys which are at correct depth). File off the excess ridges off until the blue lines are gone & surface is smooth.

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Take a 4 1/2” right angle grinder (or the like) and fit it with a sanding disc. Then sand/grind the form you need. I suspect it’s going to be a bit messy with all the metal dust flying around! Please be mindful…Dave
 
banned for 1.5 months for suggesting someone buy it, particularly when they ask for assistance with how to make it.
I have not been banned yet which is surprising.

For the OP, as far as making it, if you have a CNC lathe in the Robotics Lab, (I do not know what a PM1127 is) it is simple line and arc programming, if only a manual lathe dispense with all of the pesky radii and put generous chamfers on everything and be done with it. It will not look as old school however, I have found that if you add a large amount of uneeded holes younger people seem to like this. I have a nephew that is an avid surf fisherman that begged me to drill holes in his reel parts, when I asked him what they did he said nothing but they look cool and everyone else it doing it.

When drawing parts in a CAD system it is easy to forget that you may not have the equipment to actually make the part as drawn, being able to draw something a given way does not mean that you should. If this is a teaching moment for the students make sure that they understand this.
Like so.
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A CNC conversion for that lathe seams like a good project for a robotics class.
 
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