As I am older than many here, I do remember these and you made them correctly, as I remember (1960's) the crosshatching as being rather unique as you have done so.. and I am surprised that no one has brought this up. Your chef will be delighted as there is a high likelihood that this will be noticed.. You are a man of the trade consistently using time pr oven techniques.
About forty years ago an old machinist gave me a hint on how to do this. Last year I finally was able to use this method. I rebuilt a $4000 dollar three way ball valve. The ball was about three inches in diameter. I had similar results. Made it from 303 SS. A circle of any diameter can be inscribed any place on a sphere.
I dont understand, a circle of diameter larger than diameter of sphere cannot be inscribed on the sphere. A circle of diameter less than or equal to the diameter of sphere can be inscribed.
@@subuktageenfarooqi5712 If you use the muscle between your ears, you might understand that a circle of larger diameter than the sphere you are generating will not work. But if the circle has a diameter that is equal to or less than the diameter of the sphere,and the centers of rotation intersect, a perfect sphere will be generated.
The math there was a bit off: the hypotenuse is touching the ball in the free end, but not on the shank end. You used the ball diameter on the long leg, but I think it should have been used on the hypotenuse. Not that it would've made any notable difference (you got 11.1363 for the angle using the diameter for the long leg, I got 11.5925 using it for the hypotenuse), just for the sake of precision which is something I love in your approach to everything.
Stafan - Unglaublich hilfreich, um Ihren Denkprozess in Ihren Projekten zu sehen! Danke! ( English: Incredibly helpful to see your thought process on these projects! thanks! )
Nicely done! . Can I ask why you went for aluminium, not stainless or titanium? Aluminium usually rubs off black when not sealed. On a white chef’s vest.... Anodising also helps.
Thank you Stefan - oder soll Ich sagen - Danke schön Stefan for sharing this video showing your ability to solve a problem in addition to your excellent machining expertise!
Hey Stefan I saw your post about these a little bit ago and I was so so hoping you would do a video on it, the finish on these is gorgeous, Ill bet your friend is the best looking chef at their place of business now. And I have to say.... who needs a ball turner when you get such an awesome finish like that on a mill. Learning things from you all the time, thanks so much for the knowledge :)
That's a beautiful method. Bravo Tom and Bravo Stefan. The result is very impressive. I think you could also use a similar method to turn a ball shape in the centre of a length of round bar, with a cylinder coming out each side. Just need to work out your trig (if the cylinder diameters are different), with the difference between the two radii. This method would make for the nice old style three-ball handles on older machinery. For a really accurate result, I think you need to calculate a new, smaller cutting diameter. Increase the shank size to almost the sphere size to visualise the need for this smaller swept circle. For me, I would just sneak up on the right measurement using a mic, and small adjustments to the boring head. I am lazy! :)
Ades workshop has a good series of videos on making a ball turning tool post for the lathe, i did actually wonder how you would do it differently whenever it got to a bit where i thought "Stefan would put a shoulder on that..." It's very entertaining, well worth a watch, for the evolution of his ideas mid project if nothing else.
i really like this idea of yours when it comes to machining a workpiece as a double ender. I have seen it a lot in your videos on grinding endmills, but never thought about doing the same with workpieces. Here´s hoping i remember this the next time i need it.
As always, very informative, entertaining, and clever! Thank you for putting in the extra time that it takes to make and edit the video! Thank you, Stefan! :)
Stefan -- I couldn't figure out how you could cut the ball to the dead center , in my mind the shank would not allow that, I finally understood when I saw that the ball was rotating on an angle . Kick Ass video . You da man
Nice job.I made the ball turner for the lathe using a boring head but mounting it into a boring bar holder from the front of the lathe.Mounted a round button insert on the end of a short straight bar to fit the boring head.Sort of a few ideas joined together from some old Model Engineers magazine articles.Turns balls within .025mm circularity which is fine for rough work.
I can't believe you changed that lovely crosshatching for dull finish. You should have just shot those babies with some spray varnish! Great work as usual. Thanks!
Hi Stefan just to say how much i enjoy watching your videos you set attention to detail to another level, my evenings often consist of me, my laptop with head phones in.With all that is going on in the world at the moment i have found time to check out some of your older video's and have been watching your miniature colt 1911 project from about 5 years ago, which i think consists of about 10 videos that i watched back to back yesterday.I was wondering if you finished the gun as i could not find the whole project on your channel.once again thanks for uploading i learn so much just watching. Kevin
Have you done any work on your Tormach? I remember you getting it, but I don't recall seeing it in a video. (I know we don't see everything you do in your shop.)
The German phrase was tops. Like so many phrases its literal translation (which I had to check I assumed my German was at fault but no) gives no sense of what it is supposed to mean. As always, watching you work is a joy. Thanks.
Really great video Stefan. The company I worked for used to use this technique to make optical lens smoothing and polishing tools in cast iron and aluminium. Both convex (like your ball) and concave with radius from under 3mm up to several meters (almost flat). Although we rarely needed anything more than a hemisphere.
Imagine one of your button-up shirts where you remove the buttons and replace them with another button hole. You’ve got two button holes stacked on top of each other. Put the chef’s button through the button hole closest to your body so that the flat side is against your body and the bulb goes through the fabric. The front sheet of fabric goes onto the bulb of the button too. The layers are held on the shank of the button and can’t slip up over the bulb, but can be yanked over the bulb by someone else in an emergency.
Very cool 🙂 thanks for sharing! For your friend's benefit, those fasteners are called Sam Browne studs, which might make them easier to find off-the-shelf in future!
Stefan, this was a very interesting and educational video. Now I'll have to order Tom's "Sink or Swim" book -- I've already got his "Doing it Better" book. ;) I always look forward to your videos because I enjoy and learn a lot from your thought processes & techniques as you perform (mostly) precision machining.
Gday Stefan, I have never seen this done before, that works brilliantly, much quicker then using a ball turner on a lathe, thank you for showing another great technique, much appreciated, Matty
I foresee a new video segment Brian: Stunt Milling Saturdays! Would need some wide shots of you in bike gear and a crash helmet winding the mill table handles like a lunatic :)
If they used this in math class as a real world example, I probably would've paid attention! This is using a lot of basic trigonometric principles. GENIUS! Grüße aus Belgien...
I figured the correct angle to be 11.59 degrees ..... the 5mm spigot intersects the 12.7mm circle and creates a chord, which reduces the adjacent leg of the triangle to 12.187mm. The opposite leg being 2.5mm gives an angle of 11.59 degrees. And a hypotenuse of 12.44mm which should be the size of the circle scribed by the boring head around the sphere. I'm about 75% sure my math is correct ;) (but if I recall, I only got a 'C' in trigonometry) --- forgive my crappy drawing ----> i.postimg.cc/c4v4hLvC/ball-milling-math.jpg
In the words of Sheldon Cooper (Big Bang Theory): "I'd like to do the math!" I missed Lipton's version of this - so, was glad for your presentation. You did a great job of demonstrating this ingeniously simple solution! That's 1 less tool I need for my lathe.
Hi Stefan, good technique leading to a precision sphere. You did the trigonometry and calculated the 11.3 degree tilt, but you say it could be increased, am I correct, if you increase the angle, the shape is unaffected, but the open end would finish machining first, then as you continue to down feed to the stem position, the open side is cutting 'Air', your comment would be appreciated
A very interesting way of creating a ball. It's just a button so no need for any precision, but is this cutting a true sphere? If the inclined angle of the chuck was doubled and the hypotenuse side of the triangle (not the adjacent side) went through the centre of the intended ball then your ball may then be spherical.
Are you also using Cosine to calculate and set the boring head cutting tool path diameter or just eye ball? Every time I watch your video I am reminded of the need to work on my cutting tools to make them more free cutting like yours. Thanks for the video!
@@woodscreekworkshop9939 ahh... Missed that part, my apologies! My understanding is that he set it to final desired diameter (1/2") and the downfeed movement of the spindle completed the shape.
@@woodscreekworkshop9939 hmm. I see what you're saying. I assumed the tilted approach to clear the stem, still resulted in a "full diameter" cut... But that would result in the tool plunging past the centerline of the stem (on the outward side of the ball)... Maybe that's still ok, as it would be in a clearance situation?
Ooh, ooh, I've done this! I used my spin indexer to create a couple of finials in African Blackwood. After I created the spheres I indexed them 24 times & plunged the tool 0.2mm to create a lovely ornamental turning pineappley pattern.
Stefan, Essen ist gut! Definitely take care of the chef. Your point about precision adequate for the job at hand applies to many things besides machining.
For those without a wohlhaupter contraption, maybe consider using a normal rotary table set up horizontally, with your mill head tilted off-vertical, and feed using the quill.
Very clever Stefan. It looks from your diagram that the 12.7 diameter is actually the hypotenuse ie the path of the tool cutting surface, this doesn’t really matter here as the sin calculates as 11.35 degrees. Forgive me if I’ve got it wrong, it’s a long time since I was at school and didn’t like trig that much. How did you set the diameter of your cut- is it a trial and error?
I calculate the swept circle diameter to be 12.440mm (assuming 12.7mm desired sphere diameter, and 5mm shank diameter). A combination of pythag and thales theorems works (I think!). Too hard to explain in a comment, but I can show my working in a video if anyone's interested.
I would be happy to see this if you have the time and effort. My comment related to the top drawing at 16.19 where it looks like the swept area is the hypotenuse labelled 12.7 across the “tilted” axis of the milling machine (relative to the axis of the dividing head) . Thus the angle is sin of 2.5/12.7
@@stanstevens3783 Right - I see what you mean. I also went a step further and used the angle (and a few other things) to calculate the desired diameter of the cutting circle. As the supporting shank gets larger the cutting circle must get smaller. I will see what time I get to make a video, I have a couple in the queue already. Cheers, Craig
From what I remember from my Analytical Geometry classes in college I think your description might be incorrect. The apex point, on centerline cannot be the vertex point of your describing triangle, unless you are actually making a truncated plate spheroid. Just a quick thought experiment. The hypoteneuse describes the longest line on the triangle. And the Diameter is the longest line bisecting a circle. You described the Hypotenuse as being above a diameter line when you said it intersects the apex point on centerline. I'm a retired engineer what aint used that particular mathe in a bunch of years. So somebody go get a motarboard wearing pencil neck and "check my math." Otherwise a damned enthralling set of skills demonstrated. Your fineness of detail achieved without servos controling those machines is spectacular. Truly awe inspiring. Tchuss
All points of the sphere section are cut by a circular action (assuming fine enough feedrate, and slow enough rotation of the workpiece). That makes it a truncated spheroid. The oblate sphere (truncated or not) will only fit a circle in on-axis positions.
Please correct me if I am wrong. Did you not have to bring the boring bar’s circle tighter and tighter as you approached the top of the ball? I am not clear on that. Thanks for the many valuable videos. That Old Bob
No, the boring bar is already set to final diameter from the start. Hypothetically, you could simply lower the boring head to finished depth, then leave it happily spinning away and just rotate the indexer/rotary table, but that would be pretty rough on the part and the tool, which is why Stefan is slowly plunging the boring head to finish depth as the part is rotated. Whatever is the 'top' of the ball at any given time, will be cut once the rotary table has rotated 90 degrees from that position - all the cutting is happening in the horizontal plane, at the circle inscribed by the tip of the boring bar. Any part of the ball that is higher than the tip of the boring tool is just sitting inside the 'cylinder' of the boring bar whizzing around. If you're struggling to visualise it, try sticking a small piece of blutack to a golf ball, then take the cardboard tube (the cylinder inscribed by the boring bar) from inside a toilet roll and sit the end of it against the golf ball, with the blutack inside. Now rotate the golf ball around an axis close to 90 degrees to the cardboard tube, and you'll scrape the blutack right off with the end of the cardboard tube.
You might be a geek, if you say “ let’s talk about the math, just for fun”. Easy now... just joking. You are incredibly talented !! Your work speaks for itself !!
Considering the option of lost wax casting and polishing, this way is quite efficient. To make a pattern and wax forms and investing and burn out and casting and clean up could done but perhaps not as easily.
Great video! I've heard of ths but it always involved tilting the head of the mill which can be a pain. One minor error at 16:30 - the diameter of the sphere is the hypotenuse of your triangle, not the base of the triangle. You should use the sine function instead of the tangent. The correct angle is 11.35 degrees instead of 11.13. The is about 2% for this angle. That may be why you had a bit of a ledge at the spigot. If you look at a trig table, the error difference between the sine and tangent function is about 1% at around 6 degrees and will increase with the angle. This is why my old K&E Log-log-duplex slide rule has a SRT scale which allowed you to take either the sin or tan of small angles (this gives away my age). This scale was considered acceptable to 0.1 radians or 5.73 degrees. Minor detail that doesn't take away from great info.
I figured the correct angle to be 11.59 degrees ..... the 5mm spigot intersects the 12.7mm circle and creates a chord, which reduces the adjacent leg of the triangle to 12.187mm. The opposite leg being 2.5mm gives an angle of 11.59 degrees. And a hypotenuse of 12.44mm which should be the size of the circle scribed by the boring head around the sphere. I'm about 75% sure my math is correct ;) (but if I recall, I only got a 'C' in trigonometry) --- forgive my crappy drawing ----> i.postimg.cc/c4v4hLvC/ball-milling-math.jpg
I learn a lot from you Stefan . I thought I needed to make a ball turner but as it turns out ( pun intended ) I have everything I need since watching your video . Could those aluminum bobbles also be used in your flux capacitor build ???
very interesting and useful technique . i wish you would have taken the setup procure a bit farther and show how to set up the boring head to get the proper diameter. thanks for another great video.
He did. The length turned in the lathe from the face to the back face where the necked down shafts was just slightly longer than the diameter of the ball. Then in the mill, touch off on the face with the boring bar visually while the spindle is off. Then move the boring head in enough to clean up the excess, and boom.
Always good stuff to be found on your channel. You' have a gift for distilling down all manner of intricate processes, even for us novice types. I'll have to go take a gander at Tom Lipton's book. Thanks for helping me part ways with my money.
Always wondered how to do that. Thanks to you and Ox Tools. Great to see someone who can still "do the math...". I would like to build a model of out solar system as a display. Out of styrofoam. Any suggestions?
nice work, this makes me think about the feasibility of making mechanical ball joints like those found in a car's steering mechanism in the homeshop, sounds like a car accident in the making to me but also a lot of fun.
Very timely video for me, having recently had poor experience turning something similar (actually a toggle knob for a pressure switch) using a form tool on the lathe. I'll try it using my spin indexer on the mill tomorrow! My boring head screws onto the shank, so I'm guessing I'll need to grind a bar with the opposite geometry so I can run the mill forwards🤔 Also on my to do list is looking out for Tom Lipton's book👍
Wouldn't the base of the triangle be slightly less than the diameter by diameter×(1-cos(angle))? Also, given a shank radius r wouldn't you want the angle to simply be sin^-1(r/sphere radius)? That would be assuming that the boring head is set to the diameter of the desired sphere.
Thank you! As always, educational. May I ask why you used a lubricant when you parted off the blanks but not when you parted off the finished part? Cheers from the Canadian Arctic
Fantastic as always. I now have a tumbler, given to me by a friend. I'd like to start de-burring and polishing small parts in it, but there doesn't seem to be a lot of information out there about what media to use for what task, etc. Would definitely like to hear more about yours and what media you use for different jobs.
ah.....more hip joints for This Old Tony :D
I thought they were knuckles for his bionic hand... =)
:-D
@@atheistsfightclub6684 lol
I'm a machinist enthusiast. I am IN AWE of the knowledge, skill, and education needed to be a machinist. Much respect for you and all machinists.
As I am older than many here, I do remember these and you made them correctly, as I remember (1960's) the crosshatching as being rather unique as you have done so.. and I am surprised that no one has brought this up. Your chef will be delighted as there is a high likelihood that this will be noticed.. You are a man of the trade consistently using time pr oven techniques.
I also have Tom's book. It's full of good stuff. Thanks for sharing Stefan 👍
About forty years ago an old machinist gave me a hint on how to do this. Last year I finally was able to use this method. I rebuilt a $4000 dollar three way ball valve. The ball was about three inches in diameter. I had similar results. Made it from 303 SS.
A circle of any diameter can be inscribed any place on a sphere.
I dont understand, a circle of diameter larger than diameter of sphere cannot be inscribed on the sphere.
A circle of diameter less than or equal to the diameter of sphere can be inscribed.
@@subuktageenfarooqi5712 If you use the muscle between your ears, you might understand that a circle of larger diameter than the sphere you are generating will not work. But if the circle has a diameter that is equal to or less than the diameter of the sphere,and the centers of rotation intersect, a perfect sphere will be generated.
The math there was a bit off: the hypotenuse is touching the ball in the free end, but not on the shank end. You used the ball diameter on the long leg, but I think it should have been used on the hypotenuse. Not that it would've made any notable difference (you got 11.1363 for the angle using the diameter for the long leg, I got 11.5925 using it for the hypotenuse), just for the sake of precision which is something I love in your approach to everything.
That is amazing! Thank you for sharing -- I never would have thought of this creative way to make a ball
Awesome! The boring head actually can be used in the tool post on the lathe just like a ball Turner. But this looks much easier really.
Stafan -
Unglaublich hilfreich, um Ihren Denkprozess in Ihren Projekten zu sehen! Danke! ( English: Incredibly helpful to see your thought process on these projects! thanks! )
Todd, your Chermann is better than my German!
Clever method. Well done.
Thanks Joe!
Loved this. Never thought about doing it this way yet after watching it made me wonder why do it any other.
One of the most underrated videos this channel
Thank you for explaining the actual tool path at @6:36. It made it look very simple technique.
Nice video Stefan, I seen this years ago but completely forgot about it. I can not even begin to explain how much I enjoy your channel.
I seen, is that like I diot ?
You are an amazingly talented person and so very generous for sharing your knowledge. Thank you very much.
Nicely done! .
Can I ask why you went for aluminium, not stainless or titanium?
Aluminium usually rubs off black when not sealed. On a white chef’s vest....
Anodising also helps.
Wow! that was great. I have never seen that technique for ball turning.
This old Tony has done it sometimes ago
Thank you Stefan - oder soll Ich sagen - Danke schön Stefan for sharing this video showing your ability to solve a problem in addition to your excellent machining expertise!
Hey Stefan I saw your post about these a little bit ago and I was so so hoping you would do a video on it, the finish on these is gorgeous, Ill bet your friend is the best looking chef at their place of business now. And I have to say.... who needs a ball turner when you get such an awesome finish like that on a mill. Learning things from you all the time, thanks so much for the knowledge :)
That's a beautiful method. Bravo Tom and Bravo Stefan. The result is very impressive. I think you could also use a similar method to turn a ball shape in the centre of a length of round bar, with a cylinder coming out each side. Just need to work out your trig (if the cylinder diameters are different), with the difference between the two radii. This method would make for the nice old style three-ball handles on older machinery.
For a really accurate result, I think you need to calculate a new, smaller cutting diameter. Increase the shank size to almost the sphere size to visualise the need for this smaller swept circle. For me, I would just sneak up on the right measurement using a mic, and small adjustments to the boring head. I am lazy! :)
Those close ups are so satisfying to watch ! Great video
Ades workshop has a good series of videos on making a ball turning tool post for the lathe, i did actually wonder how you would do it differently whenever it got to a bit where i thought "Stefan would put a shoulder on that..." It's very entertaining, well worth a watch, for the evolution of his ideas mid project if nothing else.
i really like this idea of yours when it comes to machining a workpiece as a double ender. I have seen it a lot in your videos on grinding endmills, but never thought about doing the same with workpieces. Here´s hoping i remember this the next time i need it.
As always, very informative, entertaining, and clever!
Thank you for putting in the extra time that it takes to make and edit the video!
Thank you, Stefan! :)
awesome discussion/demonstration/build....great review at the end...
Stefan -- I couldn't figure out how you could cut the ball to the dead center , in my mind the shank would not allow that, I finally understood when I saw that the ball was rotating on an angle . Kick Ass video . You da man
Indeed. Also, it works equally well to tilt the head, on mills with this feature.
Cool ball-making technique! Thanks for sharing.
Nice job.I made the ball turner for the lathe using a boring head but mounting it into a boring bar holder from the front of the lathe.Mounted a round button insert on the end of a short straight bar to fit the boring head.Sort of a few ideas joined together from some old Model Engineers magazine articles.Turns balls within .025mm circularity which is fine for rough work.
Very, very good. Puts new idea's in me noggin.... Thanks Steve, great video!!!
I can't believe you changed that lovely crosshatching for dull finish. You should have just shot those babies with some spray varnish!
Great work as usual. Thanks!
Hi Stefan just to say how much i enjoy watching your videos you set attention to detail to another level, my evenings often consist of me, my laptop with head phones in.With all that is going on in the world at the moment i have found time to check out some of your older video's and have been watching your miniature colt 1911 project from about 5 years ago, which i think consists of about 10 videos that i watched back to back yesterday.I was wondering if you finished the gun as i could not find the whole project on your channel.once again thanks for uploading i learn so much just watching. Kevin
Stefan,you are brilliant,always enjoy your beautiful videos,please keep them coming.
great lesson thank you
Have you done any work on your Tormach? I remember you getting it, but I don't recall seeing it in a video. (I know we don't see everything you do in your shop.)
I guess it's kinda randomly asking but does anyone know a good site to watch newly released series online ?
@Zahir Eduardo Flixportal :D
@Luciano Kendall Thanks, I signed up and it seems like a nice service =) I really appreciate it !
@Zahir Eduardo no problem =)
The German phrase was tops. Like so many phrases its literal translation (which I had to check I assumed my German was at fault but no) gives no sense of what it is supposed to mean. As always, watching you work is a joy. Thanks.
Really great video Stefan.
The company I worked for used to use this technique to make optical lens smoothing and polishing tools in cast iron and aluminium. Both convex (like your ball) and concave with radius from under 3mm up to several meters (almost flat). Although we rarely needed anything more than a hemisphere.
See, this is what international collaboration gets us. Greetings from the US, stay safe out there!
Always enjoy watching your videos. Thanks for sharing your thoughts and skills with us.
George from Indiana US
Wow, and wow again - Nice!
At 16:43, saying "trig" or "math" are both totally acceptable :)
FYI the interesting lighting on the ball is called an anisotropic highlight (pointless fact for the day)
Great work Stefan
Have you friend come in and take a few close ups of how they fit onto his chef’s jacket & how the closure works... thx.
Just like the studs used with men's Formal Dress shirts.
Imagine one of your button-up shirts where you remove the buttons and replace them with another button hole. You’ve got two button holes stacked on top of each other. Put the chef’s button through the button hole closest to your body so that the flat side is against your body and the bulb goes through the fabric. The front sheet of fabric goes onto the bulb of the button too. The layers are held on the shank of the button and can’t slip up over the bulb, but can be yanked over the bulb by someone else in an emergency.
@@eliduttman315 For me that was over 50 years ago. The pain of using them is still there
Carbide radius tool with the Dremel. Wonderful.
Very cool 🙂 thanks for sharing!
For your friend's benefit, those fasteners are called Sam Browne studs, which might make them easier to find off-the-shelf in future!
Stefan, this was a very interesting and educational video. Now I'll have to order Tom's "Sink or Swim" book -- I've already got his "Doing it Better" book. ;) I always look forward to your videos because I enjoy and learn a lot from your thought processes & techniques as you perform (mostly) precision machining.
Very satisfying to watch, but I still think lathes offer more and better options for single machine manufacturing, what do you think?
Gday Stefan, I have never seen this done before, that works brilliantly, much quicker then using a ball turner on a lathe, thank you for showing another great technique, much appreciated, Matty
That’s a really cool technique. Never would have thought of that use for a boring bar. Sort of an inverse boring bar.
The inverse of me milling spherical bowls with the tilted facemill. :-) Stunt milling is always interesting and fun to see.
"Stunt milling" LOL :)
I foresee a new video segment Brian: Stunt Milling Saturdays! Would need some wide shots of you in bike gear and a crash helmet winding the mill table handles like a lunatic :)
Stunt milling = HEMI. I like it!
If they used this in math class as a real world example, I probably would've paid attention! This is using a lot of basic trigonometric principles. GENIUS! Grüße aus Belgien...
Nicely done Stefan! The 12.7mm dia. should be the hypotenuse in that trig ;-)
ATB, Robin
I figured the correct angle to be 11.59 degrees ..... the 5mm spigot intersects the 12.7mm circle and creates a chord, which reduces the adjacent leg of the triangle to 12.187mm. The opposite leg being 2.5mm gives an angle of 11.59 degrees. And a hypotenuse of 12.44mm which should be the size of the circle scribed by the boring head around the sphere. I'm about 75% sure my math is correct ;) (but if I recall, I only got a 'C' in trigonometry) --- forgive my crappy drawing ----> i.postimg.cc/c4v4hLvC/ball-milling-math.jpg
Lovely that Stefan thankyou
Thanks for the video, a neat way to make a ball!
Very nicely presented great tuition thank you
What a great ball technique..never ran across this method before !
In the words of Sheldon Cooper (Big Bang Theory): "I'd like to do the math!" I missed Lipton's version of this - so, was glad for your presentation. You did a great job of demonstrating this ingeniously simple solution! That's 1 less tool I need for my lathe.
Great job of machining. Aint Tom Lipton a clever one?
Great video! 5-6 minutes per part was much faster than I thought. :)
Hi Stefan,
good technique leading to a precision sphere. You did the trigonometry and calculated the 11.3 degree tilt, but you say it could be increased, am I correct, if you increase the angle, the shape is unaffected, but the open end would finish machining first, then as you continue to down feed to the stem position, the open side is cutting 'Air', your comment would be appreciated
Another great demonstration. Thanks.
A very interesting way of creating a ball. It's just a button so no need for any precision, but is this cutting a true sphere? If the inclined angle of the chuck was doubled and the hypotenuse side of the triangle (not the adjacent side) went through the centre of the intended ball then your ball may then be spherical.
Are you also using Cosine to calculate and set the boring head cutting tool path diameter or just eye ball? Every time I watch your video I am reminded of the need to work on my cutting tools to make them more free cutting like yours. Thanks for the video!
He shows the math near the end.
(tan)
mattmanyam yes and that’s how he determined the tilt angle. I am asking about the boring tool path diameter
@@woodscreekworkshop9939 ahh... Missed that part, my apologies!
My understanding is that he set it to final desired diameter (1/2") and the downfeed movement of the spindle completed the shape.
mattmanyam the tool path has to be smaller than the desired diameter of the ball. Stefan shows you this by placing a black rubber ring on the ball.
@@woodscreekworkshop9939 hmm. I see what you're saying. I assumed the tilted approach to clear the stem, still resulted in a "full diameter" cut... But that would result in the tool plunging past the centerline of the stem (on the outward side of the ball)... Maybe that's still ok, as it would be in a clearance situation?
Ooh, ooh, I've done this! I used my spin indexer to create a couple of finials in African Blackwood. After I created the spheres I indexed them 24 times & plunged the tool 0.2mm to create a lovely ornamental turning pineappley pattern.
Great idea! This could be a faux-knurl for a handle application too.
Stefan, Essen ist gut! Definitely take care of the chef. Your point about precision adequate for the job at hand applies to many things besides machining.
Clever machining Stefan, excellent vlog as per usual.
Thanks for sharing.
Thanks for showing this. Took me right back to 1966 when I was an apprentice and this was one of the milling / turning tests.
I am a simple man, I see a Stefan Gotteswinter video; I smash the like button.
The film at 5:00ish is some of the best machining video I have seen. Wonderfully illustration of the process, bravo!
13:45, waste -- or pieces for the game of "draughts"? 🤔 ♟️🏁
Thanks very much very nice buttons. what media do you use in your tumbler?
For those without a wohlhaupter contraption, maybe consider using a normal rotary table set up horizontally, with your mill head tilted off-vertical, and feed using the quill.
Very clever Stefan.
It looks from your diagram that the 12.7 diameter is actually the hypotenuse ie the path of the tool cutting surface, this doesn’t really matter here as the sin calculates as 11.35 degrees. Forgive me if I’ve got it wrong, it’s a long time since I was at school and didn’t like trig that much.
How did you set the diameter of your cut- is it a trial and error?
I calculate the swept circle diameter to be 12.440mm (assuming 12.7mm desired sphere diameter, and 5mm shank diameter). A combination of pythag and thales theorems works (I think!). Too hard to explain in a comment, but I can show my working in a video if anyone's interested.
I would be happy to see this if you have the time and effort. My comment related to the top drawing at 16.19 where it looks like the swept area is the hypotenuse labelled 12.7 across the “tilted” axis of the milling machine (relative to the axis of the dividing head) . Thus the angle is sin of 2.5/12.7
@@stanstevens3783 Right - I see what you mean. I also went a step further and used the angle (and a few other things) to calculate the desired diameter of the cutting circle. As the supporting shank gets larger the cutting circle must get smaller. I will see what time I get to make a video, I have a couple in the queue already. Cheers, Craig
From what I remember from my Analytical Geometry classes in college I think your description might be incorrect.
The apex point, on centerline cannot be the vertex point of your describing triangle, unless you are actually making a truncated plate spheroid.
Just a quick thought experiment. The hypoteneuse describes the longest line on the triangle. And the Diameter is the longest line bisecting a circle.
You described the Hypotenuse as being above a diameter line when you said it intersects the apex point on centerline.
I'm a retired engineer what aint used that particular mathe in a bunch of years. So somebody go get a motarboard wearing pencil neck and "check my math."
Otherwise a damned enthralling set of skills demonstrated. Your fineness of detail achieved without servos controling those machines is spectacular. Truly awe inspiring.
Tchuss
Correction:
"... truncated OBLATE spheroid..."
All points of the sphere section are cut by a circular action (assuming fine enough feedrate, and slow enough rotation of the workpiece). That makes it a truncated spheroid. The oblate sphere (truncated or not) will only fit a circle in on-axis positions.
That is a great idea for turning a sphere. Thank You.
Please correct me if I am wrong. Did you not have to bring the boring bar’s circle tighter and tighter as you approached the top of the ball? I am not clear on that. Thanks for the many valuable videos.
That Old Bob
No, the boring bar is already set to final diameter from the start. Hypothetically, you could simply lower the boring head to finished depth, then leave it happily spinning away and just rotate the indexer/rotary table, but that would be pretty rough on the part and the tool, which is why Stefan is slowly plunging the boring head to finish depth as the part is rotated. Whatever is the 'top' of the ball at any given time, will be cut once the rotary table has rotated 90 degrees from that position - all the cutting is happening in the horizontal plane, at the circle inscribed by the tip of the boring bar. Any part of the ball that is higher than the tip of the boring tool is just sitting inside the 'cylinder' of the boring bar whizzing around.
If you're struggling to visualise it, try sticking a small piece of blutack to a golf ball, then take the cardboard tube (the cylinder inscribed by the boring bar) from inside a toilet roll and sit the end of it against the golf ball, with the blutack inside. Now rotate the golf ball around an axis close to 90 degrees to the cardboard tube, and you'll scrape the blutack right off with the end of the cardboard tube.
You might be a geek, if you say “ let’s talk about the math, just for fun”.
Easy now... just joking. You are incredibly talented !! Your work speaks for itself !!
Hi Stefan, try using a bi-metal hole saw in the mill works wonders, good luck.
Bi metal hole saw! Nice one. No need to set diameter on boring head or run mill in reverse. I'll try it ...to hang all my hats up high...in brass!
@@jossfitzsimons Well? Did it work OK?
@@fredfarnackle5455 Well, circumstances changed and I'm afraid I never got to do it. Sorry for the news.
Very satisfying and very simple.
I have heard of the technique before, but first time seeing it action. Thanks for the demonstration.
Man! I hope your friend the chef makes you a nice dinner I return! Those are 4-star buttons! And some stars for the workmanship and video, too.
Considering the option of lost wax casting and polishing, this way is quite efficient. To make a pattern and wax forms and investing and burn out and casting and clean up could done but perhaps not as easily.
Great video. Learned a lot. Thanks Stefan.
Another very interesting video, thanks Stefan. I always enjoy seeing difficult work holding solutions.
Great video! I've heard of ths but it always involved tilting the head of the mill which can be a pain. One minor error at 16:30 - the diameter of the sphere is the hypotenuse of your triangle, not the base of the triangle. You should use the sine function instead of the tangent. The correct angle is 11.35 degrees instead of 11.13. The is about 2% for this angle. That may be why you had a bit of a ledge at the spigot. If you look at a trig table, the error difference between the sine and tangent function is about 1% at around 6 degrees and will increase with the angle. This is why my old K&E Log-log-duplex slide rule has a SRT scale which allowed you to take either the sin or tan of small angles (this gives away my age). This scale was considered acceptable to 0.1 radians or 5.73 degrees. Minor detail that doesn't take away from great info.
I figured the correct angle to be 11.59 degrees ..... the 5mm spigot intersects the 12.7mm circle and creates a chord, which reduces the adjacent leg of the triangle to 12.187mm. The opposite leg being 2.5mm gives an angle of 11.59 degrees. And a hypotenuse of 12.44mm which should be the size of the circle scribed by the boring head around the sphere. I'm about 75% sure my math is correct ;) (but if I recall, I only got a 'C' in trigonometry) --- forgive my crappy drawing ----> i.postimg.cc/c4v4hLvC/ball-milling-math.jpg
@@joedrouin6957 When your math skills fail you, everything can be solved by CAD. Your math is correct.
I can't believe I never thought of this! Great idea
Very good video..thanks for your time
I learn a lot from you Stefan . I thought I needed to make a ball turner but as it turns out ( pun intended ) I have everything I need since watching your video . Could those aluminum bobbles also be used in your flux capacitor build ???
I'm always fascinated by your #1s that look like lambda. Λwesome video, Stefan.
very interesting and useful technique . i wish you would have taken the setup procure a bit farther and show how to set up the boring head to get the proper diameter. thanks for another great video.
He did. The length turned in the lathe from the face to the back face where the necked down shafts was just slightly longer than the diameter of the ball. Then in the mill, touch off on the face with the boring bar visually while the spindle is off. Then move the boring head in enough to clean up the excess, and boom.
Very good information and was fun to watch.
Always good stuff to be found on your channel. You' have a gift for distilling down all manner of intricate processes, even for us novice types. I'll have to go take a gander at Tom Lipton's book. Thanks for helping me part ways with my money.
Always wondered how to do that. Thanks to you and Ox Tools. Great to see someone who can still "do the math...". I would like to build a model of out solar system as a display. Out of styrofoam. Any suggestions?
Include Pluto. Pluto matters!
nice work, this makes me think about the feasibility of making mechanical ball joints like those found in a car's steering mechanism in the homeshop, sounds like a car accident in the making to me but also a lot of fun.
Maybe if you use some pre-hard chromoly or similar. I wouldn't risk it though!
@@CraigsWorkshop yeah, I wouldn't risk it too with a 2000 lb mechanical mule.
Great project. I even have that book...guess maybe I should read it.
Thanks for sharing!
Was the boring head then set using the hypotenuse of the triangle calculated during the angle finding exercise?
Very timely video for me, having recently had poor experience turning something similar (actually a toggle knob for a pressure switch) using a form tool on the lathe. I'll try it using my spin indexer on the mill tomorrow! My boring head screws onto the shank, so I'm guessing I'll need to grind a bar with the opposite geometry so I can run the mill forwards🤔
Also on my to do list is looking out for Tom Lipton's book👍
Wouldn't the base of the triangle be slightly less than the diameter by diameter×(1-cos(angle))? Also, given a shank radius r wouldn't you want the angle to simply be sin^-1(r/sphere radius)? That would be assuming that the boring head is set to the diameter of the desired sphere.
Thank you! As always, educational.
May I ask why you used a lubricant when you parted off the blanks but not when you parted off the finished part?
Cheers from the Canadian Arctic
Fantastic as always.
I now have a tumbler, given to me by a friend. I'd like to start de-burring and polishing small parts in it, but there doesn't seem to be a lot of information out there about what media to use for what task, etc. Would definitely like to hear more about yours and what media you use for different jobs.
Walnuts shells,broken glass,sand,smaller and larger rocks/ball bearings some of the things you can try.
Eyeballs it to 15 micron. Gives it a look like, still not too bad. love your show stefan
The Wohlhaupter, makes this approach golden. Sure you could get there with a standard BB holder, but 100 x more fiddling.
How do you set the boring head radius accurately?
Nice implementation of Tom's book.
Thank you Mr Stefan for one more awesome lesson!