What kind of tooling is needed to radius a flywheel?

[C-Bag]

Could you explain this a little more? The cutter motion seems that same between the two styles.

Yeah, I’m curious too. The “one trick pony” to me is the second IMHO using the boring head. Folks say you can do concave but I’ve not seen pics. My radii turner can do concave and convex depending on where the cutter is in relationship to the pivot point. I’ve used my radii turner for making ball handles and for making the kind of crank handles on lathes and my rotary table where it requires concave and convex radii. Yeah, it’s not a tool I use everyday but it’s essential for certain work.

 

[Lo-Fi]

Building the Quorn is a huge amount of fun. I have a ball turner but not the patience for making all the handles! I get bored making more than one of anything... Mine it metric and covered in M8 cap head screws instead of the handles. Maybe once the Quorn is totally finished I'll set it up to grind a piece of HSS to firm either end of the ball handles

I've made something similar to the "Ball Turning Toolpost" in the video above. The advantage over the "boring head in toolpost" version is indeed that it can do inside radii. And it's seriously rigid. Quite a nice project actually, I did it in the lathe with vertical slide as that was all I had at the time.

 

[pontiac428]

Could you explain this a little more? The cutter motion seems the same between the two styles.

Sure, with the Holdridge type the motion is the same, but the capacity is much larger, it can be set up to work from many angles, and takes up less space over the bed. It also does very tight internal radii. That's pretty much all, it's still a ball turner. I think the Holdridge would be easy to make.

Besides, the less steel we import from India, the better. The stuff's full of hard spots and voids.

 

[WobblyHand]

Sure, with the Holdridge type the motion is the same, but the capacity is much larger, it can be set up to work from many angles, and takes up less space over the bed. It also does very tight internal radii. That's pretty much all, it's still a ball turner. I think the Holdridge would be easy to make.

Besides, the less steel we import from India, the better. The stuff's full of hard spots and voids.

How does one adjust the radius in the Holdridge? By adjusting the stickout of the cutter? Doesn't the tail of the cutting tool bit interfere with the swinging action? I've only seen that eBay one I linked, not a "real one". Can't tell from the picture how the cutter is retained.

Could one be made of 5/8" steel, or would you need to go thicker? Have a bunch of A36 plate in various thicknesses. Only have an AXA toolpost, but I have a couple of XL holders.

 

[pontiac428]

I figure you could make the frames out of anything. Cutting them out of plate would be ideal, but welding components together to make the frame would be fine. The radius is set using a simple straight edge gauge and calipers, and can reliably be adjusted in very fine steps if desired.

I'm not necessarily pitching for the brand (the big 12" Holdridge kit I have is nice, though), I am pitching for the tool type. Lots of ways to skin this cat.

See the attached manual for inspiring uses!

 

[devils4ever]

Search YouTube for a blondihacks video entitled, "Easy Radius Turning on the Lathe".

 

[Jimsehr]

I have a small cast iron flywheel that I want to turn into a gyroscope. Have a basic design cobbled up. I knew, and can plainly see I need to radius the flywheel so it fits in the cage or ring. I can fudge it, but how would one do this "for real"? Flywheel is 2"OD. Ring is 2"ID. So I need to radius the wheel so it doesn't interfere with the ring. That makes it a hair under a 1" radius.
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Can this be done with a ball turner?

I have made some radius turners and I think I have come up with a super simple ball turner. You can buy a Holdridge style or other type or use boring tool to do the radius. And if you are going to make lots of radius shapes it may be worth it. But after making a few radius shapes it might sit on your shelf for years before you use it again.
If you search this site for Jimsehr ball turner you will find lots of info on making one. If you only need one size it’s very easy to make one. And fast to set up.
Or you could use a form tool for the radius. I could make a radius form tool in about 30 minutes.

 

[savarin]

I have used a HSS tool in a long holder like a wood turning tool with a rest almost touching the edge of the work.
Seems scary to start but does work. I even used this method in my drill press before I got a lathe.
The mother of invention sure does throw up some strange ideas.

 

[C-Bag]

I figure you could make the frames out of anything. Cutting them out of plate would be ideal, but welding components together to make the frame would be fine. The radius is set using a simple straight edge gauge and calipers, and can reliably be adjusted in very fine steps if desired.

I'm not necessarily pitching for the brand (the big 12" Holdridge kit I have is nice, though), I am pitching for the tool type. Lots of ways to skin this cat.

See the attached manual for inspiring uses!

That is inspiring as I’d never seen all the attachments. Definitely something for only larger lathes. Not until you go to use these things do you get the need for clearance etc. That first pic is total caca de toro as there is no way that exact setup cut that ball because there is no clearance at the root for the cutter.

 

[WobblyHand]

That is inspiring as I’d never seen all the attachments. Definitely something for only larger lathes. Not until you go to use these things do you get the need for clearance etc. That first pic is total caca de toro as there is no way that exact setup cut that ball because there is no clearance at the root for the cutter.

That blurb was quite useful to show how it all worked. Like the idea of a direct mount on the compound as well, although that means there's little or no height adjustment.

Have to agree with you on the first ball picture, don't see how the cutter could get that far in without hitting things.