Need to make "sphere on a stick"

[kns1313]

I need to make a special grinding head for another hobby. Spindle will be 3/8" diameter with a ball at the end. Diameter of balls will range from about 9mm to 25 mm. How do I make a spherical head at the end of the spindle? All I have is a completely manual machine, no CNC, no CAD/CAM, just Mark 1 eyeball, good hands, and good calipers.

Scott

[Geof]

Mill or lathe? It is possible to machine spheres on either.

[kns1313]

Sorry about that. Question refers to do it on a lathe, although I'll take mill procedures also.

Scott

[thkoutsidthebox]

A guy in another thread mentioned a method to manually mill spheres. I'll look for it and post the link. It was facinating.

[thkoutsidthebox]

Here it is!

Read from post number 65.

http://www.cnczone.com/forums/showth...?t=4624&page=2

[Mcgyver]

check out
http://bbs.homeshopmachinist.net/showthread.php?t=23626
for good list of the many ways to do this.

[Geof]

Originally Posted by thkoutsidthebox A guy in another thread mentioned a method to manually mill spheres. I'll look for it and post the link. It was facinating.

So now I am just "A guy" ???? Thank you very much, after all the advice I have given you!!! A guy....sheesh...young people these days don't give us old farts any respect.

[RICHARD ZASTROW]

Geof, You're just too sensitive. I think Adobe Machine is older than you and he's older than dirt. I'm older tha AM which makes me older than older than dirt. That almost qualifies you for "Young Fart" Does that make you a "Sensitive, relatively young,[savage] fart-guy"? But I digress.

[thkoutsidthebox]

lol...you all crack me up! But technically Geof, it was fizzissist who was the random guy who proposed the idea...tut tut, trying to steal the glory!!

[Geof]

Originally Posted by thkoutsidthebox lol...you all crack me up! But technically Geof, it was fizzissist who was the random guy who proposed the idea...tut tut, trying to steal the glory!!

Go back and read; I was the one who posed the question and the one who gave the detailed description. I don't need to steal glory.

Mr Zastrow considering you called me sensitive, a much better epithet than the other 's' word I have to admit you are probably not a bad old Dick .

And so I don't get accused of being frivolous here is some stuff about ball making. First three pictures are a ball generating attachment I made for a small mill. The ball is rotated by the electric drill on the inclined rotating axis on the table. Raising the table moves the ball into the cutter. The crucial thing is that the spindle axis and the ball's axis of rotation are co-linear. With a dial gauge clamped to the spindle housing and reading on the table we could make brass balls consistently spherical and to size 0.812" to 0.813". We made thousands this way starting in the early nineties before converting to CNC around 2001. This method is one based on a ball generating machine I built as a third year apprentice in 1963 for doing balls for ball valves. The 1963 machine was still working producing parts in 1996 when I visited the company.

EDIT: The pictures are taken using a mirror which is why it looks like two machines.

Remaining pictures are a lathe attachment for making hemispheres on the end of round bar. I turned a piece of Delrin as an example. This was made for a much bigger machine. The tool rotates around a horizontal axis which has to be co-linear with the lathe spindle and the tool has to be centered directly above the spindle centerline. Again this attachment did thousands of hemispheres between 1987 and 2001 when we put the part on a CNC lathe.

It is also possible to have the tool rotate around a vertical axis on the lathe but the horizontal mechanism allows it to be clamped in a normal tool post.

[thkoutsidthebox]

Originally Posted by Geof Go back and read; I was the one who posed the question and the one who gave the detailed description. I don't need to steal glory.

Thats true Geof, and there was no offence meant.

You did say: "How many people do you know that do it that way?", which gave me the impression that you hadn't ever done it that way.

Re the rest of your above post, all I can say is WOW. Very cool.

[Geof]

Originally Posted by thkoutsidthebox Thats true Geof, and there was no offence meant. You did say: "How many people do you know that do it that way?", which gave me the impression that you hadn't ever done it that way. Re the rest of your above post, all I can say is WOW. Very cool.

Okay I will stop being a crotchety old geezer

I am flattered by your appellation 'cool' but some time you should find a place doing spheres on a CNC lathe. I think that is cool. To me the cool part is that as the tool traces the curve the two axes are running at constantly changing speeds and the X changes direction as it goes past the largest diameter. Yet even with an inexpensive lathe like the Haas Toolroom lathe the sphere is so good you cannot measure any imperfections with a regular micrometer. I posted some pictures in a different thread showing spheres made on a Haas TL1. http://www.cnczone.com/forums/showthread.php?t=35425