Ball Turning Device

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RSG
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Re: Ball Turning Device

Postby RSG » Tue Oct 17, 2017 11:01 pm

Thanks guys! I'll post a drawing of the part in the morning.
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RSG
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Re: Ball Turning Device

Postby RSG » Tue Oct 24, 2017 9:24 am

Sorry for the delay, here's the part I was talking about making. The inside is no issue as it could be machined first then screwed onto a bar of aluminum as a fixture to turn the radius. Anyone see any issues with this?

Image
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earlgo
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Re: Ball Turning Device

Postby earlgo » Tue Oct 24, 2017 1:45 pm

A ball turning device similarly constructed to mine would need a longer bar to support the tool holder, but it could work as the radial clearance up and down is enough.
BTD&C#1.jpg

I'd bet Mr. Howe's method would work better, with some adaptation.
--earlgo

RSG
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Re: Ball Turning Device

Postby RSG » Wed Oct 25, 2017 8:51 am

Thanks Earlgo!

I'll have to work on something like that. I might find a way to incorporate my existing top slide to reduce the amount of time building it.
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RSG
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Re: Ball Turning Device

Postby RSG » Wed Oct 25, 2017 8:57 am

Conrad_R_Hoffman wrote:Pictures of mine here- http://www.conradhoffman.com/ballturner.htm

I find the hardest part of the whole thing is getting the tool position exactly right for a perfectly spherical ball. Not-quite-spherical balls are very easy.


I must have missed this earlier Conrad! Thanks, it's another viable option.
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whateg0
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Re: Ball Turning Device

Postby whateg0 » Wed Oct 25, 2017 12:11 pm

My guess is that you'll need to have a long mandrel to mount the work on so that the part of the tool that rotates can be slid under it 6" closer to the headstock. Then run the TS end of the mandrel on a center and it should work.

RSG wrote:Thanks Earlgo!

I'll have to work on something like that. I might find a way to incorporate my existing top slide to reduce the amount of time building it.


you'll have be cognizant of the tool pressure. Hanging the tool 6" off of the compound may induce some chatter depending on how rigid your lathe is. Looks like Earlgo's version should be less susceptible, but it's still quite a bit of tool hanging over dead air.

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WesHowe
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Re: Ball Turning Device

Postby WesHowe » Wed Oct 25, 2017 5:15 pm

Not just the vertical clearance is at play here. Convex curves with the "conventional" ball turner designs require the pivot to be closer to the spindle than the cut surface. For a larger radius that is a problem, as you either have interference between the chuck and the pivot, or you have to hang the work out a long way. For a 1" or 2" ball, this is not much of a problem.

RSG
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Re: Ball Turning Device

Postby RSG » Thu Oct 26, 2017 8:50 am

Good points above^ and I am going to review the whole thing prior to moving forward. I have also designed an option that doesn't require a large radius and may just go that route depending on all the things mentioned above.
Vision is not seeing things as they are, but as they will be.

whateg0
Posts: 382
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Location: Wichita, KS

Re: Ball Turning Device

Postby whateg0 » Thu Oct 26, 2017 8:53 am

WesHowe wrote:Not just the vertical clearance is at play here. Convex curves with the "conventional" ball turner designs require the pivot to be closer to the spindle than the cut surface. For a larger radius that is a problem, as you either have interference between the chuck and the pivot, or you have to hang the work out a long way. For a 1" or 2" ball, this is not much of a problem.


If the part can be flipped and doesn't require TS support, the radius tool can be placed at the TS end of the lathe. Alternatively, if the tool is made such that all of the support is done below the work, it will reside beneath it, just like the carriage would, but I guess that depends on the definition of "conventional" here.


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