You might guess that I wouldn’t have a new ball ready so fast after the last fiasco. Well, I did get out to the shop long enough to turn a new one today.
I used a new method to turn this ball, and I think it is the best one I’ve done so far. Nothing original about the way I did it, but new for me. It could be that many of you out there aren’t interested in turning Chinese balls, but I would think most turners would like to try their hand at doing a ball sometime, so I thought I would share this method with you. It’s mostly photos and not too much babble, so I hope you will have a look.
Mounting the workpiece between centers
Turned down to the finished diameter and marked with the ball’s diameter and a centerline.
A spigot is turned to fit into my 4 jaw chuck.
Mounted in my 4 jaw chuck and with the tailstock brought up and locked in to ensure stability and accuracy. I have also turned it down to make the 25mm axles (left thick for stability).
Here you can see the template and that it fits the circumference of the workpiece.
I have partially turned the ends at 45 degree angle and you can see what is left to turn by the template. I used a wide round nosed scraper up to this point. It doesn’t really scrape, it cuts. You can get A nice smooth cut without have to worrry too much about cutting too much off as you might with a gouge.
I have been using a gouge since the last photo because I can cut closer to the axles. You have to use good technique on these cuts to get them smooth and consistence since you are working more or less on vertical surfaces. A check with the template indicates that we are getting closer.
continuing with the gouge and also using the scraper again on surfaces closer to the centerline. Not far to go now.
Almost there! Note that the axles are turned down. Be careful with the axle on the headstock side because you will need it to be strong enough to eventually turn the ball without the tailstock in place.
Ok, this is pretty close. I think it will be easiest, safest and quickest to start sanding from this point.
The template shows that it is perfect. Now I just have to get those axles turned off.
The tailstock end is parted off and you can see the nub.
The toolrest is brought up and the nub turned off.
A little sanding and a check with the template, Bingo! Take your time with this. It’s not overly easy to get that nub off and even with the rounded surface of the ball.
The ball parted off from the chuck. Now the last remaining axle nub has to be turned off.
The ball is mounted in my ball chuck and the last nub turned off and sanded smooth. If you don’t have a ball chuck, you can just turn a cup with the same radius as the ball, place the ball in the cup and bring your tailstock up and lock the ball in place, turn off as much of the nub as possible, sand and then remove the ball from the lathe, cut the remaining tiny nub off with a chisel and then sand by hand.
And here it is, the finished ball.
Some helpful tips
1. Take extra care to get your diameter right when you rough down the workpiece so you know exactly what it is.
2. Very important to keep your tool cutting edges as close as possibel to the horizontal center-point of the workpiece
3. Make sure that the length of the workpiece between your marks is exactly the same as the diameter and that the centerline is truly in the center.
4. When you reduce the diameter of your axles make sure you don’t cut too close and make the end of the ball flat. It is easier to do than you might think.
5. After the initial roughing of the ball you have to stay focused as it is easy to cut to much off, especially with the gouge. Keep an eye on the ball profile as you turn and take light cuts and check often with the template. Some turners use a water glass or other round container to check the ball’s roundness with, but that doesn’t tell you if are at the right diameter, so I prefer the template.
Thanks for reading and I hope you find something interesting here. Below are links to this series.
-- Mike, an American living in Norway.