Ball Turner Experience

[Jimsehr]

Rex
It was a 3/8 ball in a 5/8 ball in a 7/8 ball in a 1 inch cube. Each entry hole is .06
smaller than the balls.

 

[Rex Walters]

Unreal

 

[Rex Walters]

Woo hoo!

I should have made me one of these things sooner! I'll start another thread to stop spamming this one, but Jim's ball turner works a treat. Smart man.

I made one for 3/4" balls:




That's the finish in a piece of 3/4" diameter 12L14 directly from the tool. It's effectively a turning tool with a huge radius, so the finishing pass leaves an outstanding finish (and it's spot on dimension wise).

Here are the parts:




There are 4x 3/8-24 set screws to secure it in the tee slot (I didn't have any flat set screws on hand, so faced off the cup points so as not to mar up the bottom of the tee slot in my compound). The puck has a 1/4" long 1/4" diameter boss on the bottom that has a hole in it tapped for the 10-32 SHCS. The tee nut has a reamed 1/4" hole for it to ride in. You adjust the nuts so that is swivels freely, then lock it with the jam nut. I set it a little too tight for the inaugural run (out of fear) but it turns out that it's amazingly forgiving (it would probably work just fine without the screw at all). I made the hole 0.001" oversize, which has a terrifically solid feel in use.

The cutter is locked with a set screw from the side at cutter height. I used the 1/8" diameter shank from an old end mill. I ground it on my Quorn T&C grinder, but a pedestal grinder or bench grinder would have worked just as well.

To use it, you just bump the cutter up against a faced edge of the work, then lock the carriage. Retract the cross slide, then feed in a little at a time as you swing the puck back and forth. It cuts like butter and is surprisingly fun.



Note that it's NOT necessary to plunge in a parting tool beforehand to make the reduced neck diameter as show in the photo. That's the normal trick for using form tools or whatever, but with this ball turner you can just swing-plunge the cutter in to whatever depth you want. It acts like a very rigid form tool when you plunge like that. With a steady hand, you can even traverse the carriage to turn a longer neck at a fixed diameter (just holding the handle in place).

ALSO: note the 3/4" Morse taper collet. My little 10" lathe has too small a spindle for 5C collets, and can only use 3C/3AT which only go up to half inch diameter. You can buy a set of 3MT collets quite cheaply on Amazon or other outlets for offshore tooling, and they let you use collets for stock up to 3/4" diameter. I just use a piece of 3/8" allthread as a drawbar (with a cheap lawn-mower wheel from Harbor Freight and a homemade arbor that registers against the left end of the spindle). I use a swing press to bang out the collet when I'm done (still need to make something more elegant).

For this kind of hand pivoting, it's much more rigid and safer to use a collet that lets you get right up next to the spindle, than to have your hands near the spinning jaws of death in a chuck. Remember that you have to swing the handle almost 180 degrees to turn a ball.

I'll make a few more cutters for smaller diameters, but mounted on my cross slide, 3/4" diameter balls are about the maximum unless I thin out the puck considerably (which doesn't give the cutter much support). If I mount it on the cross slide, I can get much larger balls.

It looks sketchy, but is astonishingly solid and not touchy at all.

Here it is in action:

I was filming one handed and the spindle speed was much too low, so it's a little jerky. You can take pretty aggressive cuts without any issue, and even the little 1/8" cutter I was using is effectively a huge (and perfect) nose radius for a fantastic finish on the finishing passes as I mentioned.

Beyond simply turning a ball, the tool is great for making precise convex fillets at the end of a part or the outside diameter of a shoulder. It's also useful for making concave fillets at the base of a shoulder: either using the cutter as a precise form tool (which is still larger than the nose radius of a turning tool normally) or actually swinging a radius if you need a really large concavity.

 

[WobblyHand]

Thanks for writing this up. I had seen Jim's ball turner and didn't quite understand it. Your pictures make it a bit clearer. Think I will make one. This seems like even an amateur like myself could pull this off!

 

[rwm]

Wow, you guys have balls!
Something else to consider. Almost all of my spheres end up getting threaded for attachment. This is hard to do after they are made. I have made a few dedicated mandrels with threaded ends to hold the work while turning. I start with barstock that is cut so length=diameter. I then drill and tap one end and screw it onto the mandrel. Works out great.

 

[Rex Walters]

Almost all of my spheres end up getting threaded for attachment.

The Quorn levers have balls of different diameters at each end, with a tapered shaft between them, then the larger ball gets a flat on one side at an angle and then a blind hole drilled and tapped.

It’s a tricky bit of machining. It can all be done on the lathe, but you need a cup live center and a collet with a stop to mill the taper with your tailstock set over. You also need a fixture to hold the lever at an angle for facing the flat and boring and tapping the blind hole.

More commonly, you make a complete sphere with a bored and tapped blind hole that you screw on to a handle. That’s easy with Jim’s turner: you make a ball on the end of a rod with a thin “neck”. Then face, bore, and tap the hole. Part off the ball at the neck (leaving some extra material. Turn a stub arbor, thread the end, screw on the partially completed ball, then use the ball turner to remove the extra material and blend the surface. Polish it up to a mirror if you want.

(Or do as Robert suggests and face, bore, and tap the hole in the end of a shaft, then part off while still cylindrical with the length equal to the diameter. Then thread it onto the sacrificial arbor and turn the ball in one shot. I just now understood what he meant!)

I’ll demo both if these in another thread.

The more I think about it, I think the screw from below is unnecessary if you turn a boss like I did. Jim uses a screw from above and uses the screw as the pivot, but I prefer the boss since I can turn it one thou smaller than whatever reamer I happen to have available for a very precise fit. The boss in the bottom also allows me to get a cutter as close as I want to the pivot point, so I can make very small radii ball and fillets.

 

[Jimsehr]

Unreal

Good afternoon - just wondering if anyone has had experience with the large ball turner from Little Machine Shop - specifically will it work on a 12' swing Clausing lathe and how does it perform cutting steel.

Thanks
Rick

Good afternoon - just wondering if anyone has had experience with the large ball turner from Little Machine Shop - specifically will it work on a 12' swing Clausing lathe and how does it perform cutting steel.

Thanks
Rick

Here are a few pics of balls turned with my Jimsehr super simple ball turner.
After turning them I held them a 5c collet sawed them off ,then drilled and tapped then.
jimsehr


edit if going to hold ball in collet you should use a 5c type collet or put a matching size plug in back part of collet to get a solid grip on ball. Easy to do.
jimsehr

 

[Janderso]

Woo hoo!

I should have made me one of these things sooner! I'll start another thread to stop spamming this one, but Jim's ball turner works a treat. Smart man.

I made one for 3/4" balls:

View attachment 455019


That's the finish in a piece of 3/4" diameter 12L14 directly from the tool. It's effectively a turning tool with a huge radius, so the finishing pass leaves an outstanding finish (and it's spot on dimension wise).

Here are the parts:


View attachment 455021

There are 4x 3/8-24 set screws to secure it in the tee slot (I didn't have any flat set screws on hand, so faced off the cup points so as not to mar up the bottom of the tee slot in my compound). The puck has a 1/4" long 1/4" diameter boss on the bottom that has a hole in it tapped for the 10-32 SHCS. The tee nut has a reamed 1/4" hole for it to ride in. You adjust the nuts so that is swivels freely, then lock it with the jam nut. I set it a little too tight for the inaugural run (out of fear) but it turns out that it's amazingly forgiving (it would probably work just fine without the screw at all). I made the hole 0.001" oversize, which has a terrifically solid feel in use.

The cutter is locked with a set screw from the side at cutter height. I used the 1/8" diameter shank from an old end mill. I ground it on my Quorn T&C grinder, but a pedestal grinder or bench grinder would have worked just as well.

To use it, you just bump the cutter up against a faced edge of the work, then lock the carriage. Retract the cross slide, then feed in a little at a time as you swing the puck back and forth. It cuts like butter and is surprisingly fun.

View attachment 455022

Note that it's NOT necessary to plunge in a parting tool beforehand to make the reduced neck diameter as show in the photo. That's the normal trick for using form tools or whatever, but with this ball turner you can just swing-plunge the cutter in to whatever depth you want. It acts like a very rigid form tool when you plunge like that. With a steady hand, you can even traverse the carriage to turn a longer neck at a fixed diameter (just holding the handle in place).

ALSO: note the 3/4" Morse taper collet. My little 10" lathe has too small a spindle for 5C collets, and can only use 3C/3AT which only go up to half inch diameter. You can buy a set of 3MT collets quite cheaply on Amazon or other outlets for offshore tooling, and they let you use collets for stock up to 3/4" diameter. I just use a piece of 3/8" allthread as a drawbar (with a cheap lawn-mower wheel from Harbor Freight and a homemade arbor that registers against the left end of the spindle). I use a swing press to bang out the collet when I'm done (still need to make something more elegant).

For this kind of hand pivoting, it's much more rigid and safer to use a collet that lets you get right up next to the spindle, than to have your hands near the spinning jaws of death in a chuck. Remember that you have to swing the handle almost 180 degrees to turn a ball.

I'll make a few more cutters for smaller diameters, but mounted on my cross slide, 3/4" diameter balls are about the maximum unless I thin out the puck considerably (which doesn't give the cutter much support). If I mount it on the cross slide, I can get much larger balls.

It looks sketchy, but is astonishingly solid and not touchy at all.

Here it is in action:

I was filming one handed and the spindle speed was much too low, so it's a little jerky. You can take pretty aggressive cuts without any issue, and even the little 1/8" cutter I was using is effectively a huge (and perfect) nose radius for a fantastic finish on the finishing passes as I mentioned.

Beyond simply turning a ball, the tool is great for making precise convex fillets at the end of a part or the outside diameter of a shoulder. It's also useful for making concave fillets at the base of a shoulder: either using the cutter as a precise form tool (which is still larger than the nose radius of a turning tool normally) or actually swinging a radius if you need a really large concavity.

I’ll have to make one as well.
Your thread will be watched with interest.
Thanks for sharing Rex.

 

[Jimsehr]

Rex is so much better than I Using a computer. He is going to post about how to use the same jimsehr super simple ball making tool to make a BALL or cut a CONCAVE radius into the od of a bar of stock. So you end up with 2 tools in 1. And why to make several radius pucks.
And if any one wants to make the tool and does not have a mill contact me an I will tell them how to make tool using only a lathe.

jimsehr

 

[Rex Walters]

if any one wants to make the tool and does not have a mill contact me an I will tell them how to make tool using only a lathe

And I will bet anyone a dollar that he will show you how to do it WITHOUT using a four-jaw chuck.