# Best Homemade Tools >  Single piece, simple ball turner.

## tonyfoale

I need to make some engine pushrod ends with a ball shape. In the past I have done this with carefully ground form tools. There can be two problems with this approach. Firstly, form tools can cause chatter and secondly there is a question of how accurately the shape is.
I have been thinking of building a ball turning attachment for several decades but there has rarely been a real need. i only make tools when I have a current need.
My initial ideas centred around "conventional" devices but as I was searching for suitable lumps of metal a much simpler and minimal work idea emerged. Most/all systems that I have seen pictures of don't seem to have a means of fine diameter adjustment. This is an important requirement for me. I guess making door knobs or lathe handles doesn't need it. Then I thought that I needed something like a compound rest slide to mount the tool on for diameter adjustment. That idea led me to ask why build something else when the cross slide can be rotated and is probably more securely held than the small pivots used by many designs of ball turners? So this meant that I only had to make a single piece, a tool holder that would put the cutting edge near the rotation axis of the compound rest. Job done. 
Before use I'll need to clock up the the hole that the compound rest pivots on to centralize that using the cross slide and then lock it in place. That will put the rotational axis on the same longtitudinal vertical plane as the centre of the work piece, ensuring a circular ball rather than a distorted circle with pointed ends as is often seen on winding handles. Perhaps I should make some form of stop to eliminate the clocking each time.
There is one principal disadvantage with this design. The cutting edge of the tool is set a fair way back and the saddle can't get close enough to a chuck without a lot of workpiece overhang. There is also a compound rest rotational clearance problem ​with a normal chuck. Not so much of a problem with 25 mm and above material if the work piece is long enough to give enough overhang. For smaller diameters I have found that an ER25 collet chuck with a 5C shank held in a chuck on the parallel section works well. This ball turner is suitable for a wide range of ball diameters up to around 40 mm diameter, which is far larger than any anticipated work.
So i dug out a suitable steel block from the scrap bin and did the minimum amount of milling to enable tool holding and to give work piece and collet chuck clearance. I like to leave the maximum amount of metal in place for rigidity and general mass. I decided to build it to take 1/2" square insert lathe tools because it will give me great flexibility in the choice of cutting tool shapes. I machined the height of the floor of the tool mounting to put the cutting edge at the centre height of the work piece.

 
The machined tool holder block compared to the original lump of steel.

 
The block bolted in place on the compound slide in place of the usual tool post. The odd shapes milled away are for clearance as the compound rest is rotated.

 
Machining a 25 mm diameter ball end. Note the required overhang and the closeness of the fixed section of the slide to the chuck.

 
Machining a 12 mm ball end held in the ER25 collet. Since this photo was taken, more clearance material has been machined away and the overhang from the collet has been greatly reduced.

I don't claim that this is anywhere near the best ball turner out there but it does a great job and it must be one of the simplest to make and it is a solid and rigid implementation. I love simplicity and minimum work.

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Canobi (Sep 3, 2018),

high-side (Jul 4, 2020),

LMMasterMariner (Aug 15, 2017),

mwmkravchenko (Sep 3, 2018),

olderdan (Aug 15, 2017),

old_toolmaker (Jun 5, 2021),

Paul Jones (Aug 18, 2017),

Ralphxyz (Jun 12, 2021),

rossbotics (Aug 16, 2017),

Seedtick (Aug 16, 2017),

Tonyg (Sep 4, 2018),

Tuomas (Mar 7, 2018)

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## tonyfoale

here are a couple more pix. making a pushrod end, the base reason for making this ball turner. I mentioned that one of the reasons for making it to accept insert type lathe tools was the choice of cutting edges that can be used. Here I am using a round insert which leaves a smooth finish and blends nicely into the rest eliminating stress concentration.

 
Two views showing the turning of an 8 mm ball for a pushrod end cap. Click images for full size versions.

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LMMasterMariner (Aug 15, 2017),

olderdan (Aug 15, 2017),

Paul Jones (Aug 18, 2017),

Ralphxyz (Jun 12, 2021),

rossbotics (Aug 16, 2017),

Seedtick (Aug 16, 2017),

Tuomas (Mar 7, 2018)

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## olderdan

Nice simple sturdy solution, I use my boring head in the up and over mode but do not have the precision requirement that you need, mostly for acorn nuts.

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Okapi (Sep 4, 2018)

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## tonyfoale

> Nice simple sturdy solution, I use my boring head in the up and over mode but do not have the precision requirement that you need, mostly for acorn nuts.



i did actually consider using a Criterion style boring head instead of making the tool holder but on balance i decided against it.

A memory damaged by age is a terrible thing. i remembered as soon as I finished it that I had previously considered two other methods for making ball ends. 
1. i described a T & C grinder that I made in an earlier post to this forum. If I change the grinding wheel for an end mill then I could make balls on that.
2. I could put the work piece in the mill spindle and a lathe tool in the vice, sprinkle in a bit of G-code and hey presto.

Why wasn't it before I made this ball turner that I remembered these almost zero work options?

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Seedtick (Aug 16, 2017),

Tonyg (Jul 2, 2020)

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## DIYer

Thanks tonyfoale! We've added your Ball Turning Fixture to our Machining category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:















Ball Turning Fixture
 by tonyfoale

tags:
ball turning

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## Toolmaker51

> (abbreviated) A memory damaged by age is a terrible thing. i remembered as soon as I finished it that I had previously considered two other methods for making ball ends. Why wasn't it before I made this ball turner that I remembered these almost zero work options?



Well you mentioned considering a ball turner for decades. Both other solutions are feasible, perhaps turning beats milling by eliminating 1 axis?
Any how, it seems memory is subject to more than just age...Few of us can create items quicker than conceive them.

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tonyfoale (Aug 16, 2017)

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## tonyfoale

> ...... Both other solutions are feasible, perhaps turning beats milling by eliminating 1 axis?



You have lost me there, I see 3 axis involved either way.
In the lathe you have the rotary workpiece Z axis, the rotary Y axis of the compound rest to describe the ball circle and a linear axis of the compound slide for diameter adjustment.
On the mill you have the Z workpiece spin axis, the linear Z axis to traverse the work and either the linear X or Y axis (user or G-code programmer's choice) to trace out the shape and size.
If you have a rotary 4th axis on the mill then you would still need 3. The spin of the 4th axis, the traverse of the X axis and the linear Z axis for the shape and size.
I don't have a 4th axis yet but I have my eyes open for a small lathe head which I would drive either with an induction motor to use it as a high speed lathe or a stepper motor to use as a CNC 4th axis. A change of belt or a dog clutch would allow rapid swap between the two modes. Although my mill had only 3 axis control I took the precaution of setting up the control stuff for 4 axes to allow easy addition of a 4th.

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Wmrra13 (Mar 6, 2018)

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## Ralphxyz

I am just getting started with using a lathe and have a ball turner on my list of things to do.

Where is the pivot on you tool? Sure wish I could could see things live, posible a video of it in action would help.

But thanks!!

Ralph

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## Toolmaker51

> You have lost me there, I see 3 axis involved either way.



I'm thinking along the set-up, manipulating knee and quill Z's [prior to locking] wherein lathe that's more 'built-in' addressing centerline. Maybe better size control too? Can think of last occasion to ball turn, no-one had the lathe version, used a boring head though. Difficult to get proper finish, heads aren't too great for decent corner radii on cutters. I wouldn't spend effort on form tool even with means to generate accurate cutter, on something like a push rod.

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## Y-geo

Ralph,
from my "library " :-




It is one of the variant "ball making Jigs " available commercially I have not seen (so far ) a how to make your own ball making jig/fixture.

PS you are in luck this is ONLY 23 mins long lolz

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Frank S (Mar 7, 2018),

Paul Jones (Aug 18, 2017),

Tonyg (Sep 4, 2018)

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## mklotz

I've made several ball cutters for the lathe but I still prefer my incremental cutting method for non-critical (most are) spheres. If you care to explore it, download the BALLCUT archive from my page.

For the benefit of neophyte ball cutter users...

To form a proper sphere with a ball cutter, the axis about which the cutter turns must be in the same plane as the axis of the part being turned, i.e., the lathe Z axis.

If this isn't true you'll end up turning some variation of an ogive...

https://en.wikipedia.org/wiki/Ogive

OTOH, if you want to turn an ogive intentionally, the program included in my OGIVE archive will be of help.

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Paul Jones (Aug 18, 2017),

Y-geo (Aug 16, 2017)

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## Ralphxyz

Thanks Y-Geo, that is what I was referencing I see the pivot point on the Repton R1 but do not see a pivot point on the subject.

I don't even see a handle to make the pivot.

Ralph

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## Toolmaker51

Yep 23 minutes of youtube is like a semester.
There are two commercial radius attachments that have been around the longest. Eagle Rock (Shapley design) and Holdridge. Holdridge were very prevalent, still made, suited up to large lathes. The $$$ is large too, but reasonable on the auction sites. They use leverage ratio over the cutter to get smooth finish. A long handle provides control over feed rate. 
The Eagle is geared and screw driven, also manually, and from an individual perspective more appropriate for personal use. Either uses simple mechanics and could be shop made with some pivot bushings or bearings and a bandsaw. Tony's is simpler yet, entirely milled. 
Either way, the idea is to locate tool tip a specific distance from the axis it swings on. + is concave, - is convex. 
In mating parts, I'd cut ball first, polish, and blue into a socket. You normally wouldn't seek perfect contact at the dead centers. A flattened ball contacting more surface area should wear better.

Awestruck, Marv. details for spheres and ogives!

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Paul Jones (Aug 18, 2017)

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## tonyfoale

> I'm thinking along the set-up, manipulating knee and quill Z's [prior to locking] wherein lathe that's more 'built-in' addressing centerline. Maybe better size control too? Can think of last occasion to ball turn, no-one had the lathe version, used a boring head though. Difficult to get proper finish, heads aren't too great for decent corner radii on cutters. I wouldn't spend effort on form tool even with means to generate accurate cutter, on something like a push rod.



i am still having problems following but no matter. I would not lock the quill Z because that is what gives the traverse movement along the workpiece. i have used form tools for the ends of pushrods in the past without problem but of course you have to make a different tool for each ball diameter. i am only interested in using aluminium and small diameter balls so it is not too arduous for a form tool. Anyway now that i have this direct method of turning small balls I won't be using form tools for this purpose anymore.

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## tonyfoale

> I am just getting started with using a lathe and have a ball turner on my list of things to do.
> 
> Where is the pivot on you tool? Sure wish I could could see things live, posible a video of it in action would help.



Ralph,
The pivot is the compound rest pivot. It already exists and (at least in my case) was a very good fit with no discernable slop. Using that is what makes this implementation so simple. I did make a short video, I'll edit it when I get a moment and put it on You tube.

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## tonyfoale

> I don't even see a handle to make the pivot.
> 
> Ralph



The compound rest is all the handle that is necessary, plenty of places to grab it. That will be clear when I post the video. I promise that it won't be anywhere near 23 mins.
There are a ton of DIY ball turners on the net, Mr. google knows about a lot of them. I expect that there are several in the archives of this forum as well, but I haven't looked. Some have low grade pivots top and bottom in a yoke construction and others have a single more substantial pivot at the bottom like this one
Free Metalworking Project Plans: Ball Turning Toolpost (Lathe, Mill) - Projects In Metal, LLC
If I were making one without the benefit of using the existing compound rest I'd make it similar to that one but I would not make the tool holder as an "L" as most do. That could be left in a triangle shape but with a concave hypotenuse for ball clearance. More metal = greater rigidity.

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## tonyfoale

> For the benefit of neophyte ball cutter users...
> 
> To form a proper sphere with a ball cutter, the axis about which the cutter turns must be in the same plane as the axis of the part being turned, i.e., the lathe Z axis.
> .



That could be subject to misinterpretation by some. There are an infinity of planes containing the axis of the workpiece, the definite article suggests that there is a single plane. In my initial post I specified the vertical plane which would be the most commonly used, although horizontal is often used as well. Theoretically you could use any of the infinity of planes as long as it contained both axes, which is in accord with your statement of course.
This where many ball turners fall down. Because they have no easy built-in depth of cut or radius adjustment it is common to use the cross slide for "diameter" adjustment but that moves all planes through the tool spin axis outside of any plane containing the work piece axis. Then you either end up with an ogive or the other extreme which is a longitudially swashed sphere with a flat or dimpled end. That is unless you arrange the tool setting such that both planes coincide when cutting at the desired diameter. Then you will start off with the swashed shape morphing into spherical as you approach size. Not easy to setup.
I wanted to be able to accurately turn part spheres which is why I knew that I had to incorporate a separate radius adjustment, other than manually moving the tool in its holder which would be tedious and hard to adjust precisely. The compound slide was a good answer to that problem. The cross slide is used to align the two previously mentioned planes only, and is then locked.

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## mklotz

The ball turner axis, when extrapolated, must intersect the rotation axis of the part. Is that wording more to your liking?

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Paul Jones (Aug 18, 2017)

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## Ralphxyz

Duh OK it is "starting" to settle in. I now can understand the pivot. Now I have to work on the operation geometry.

That video sure will help.

Again thanks for posting.

Like I said I have a ball turner on my list, this is looking rather simple for even me to make.

Ralph

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## Ralphxyz

Marv I almost understand what you are saying, I need to be at my lathe to fully grasp it, I can not just picture it.
Of course I am new to turning.

Ralph

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## tonyfoale

> The ball turner axis, when extrapolated, must intersect the rotation axis of the part. Is that wording more to your liking?



ha, ha. I can't fault that statement. Whether the wording is more to my liking is immaterial because I understand the geometry. i was just concerned that the previous may not have been clear to all.

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## Y-geo

Ralph,
Tool post pivoted ball / ogive turner in close up action :-




better yet only 5.75 mins long

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## tonyfoale

> Duh OK it is "starting" to settle in. I now can understand the pivot. Now I have to work on the operation geometry.
> 
> That video sure will help.



Ralph et al.

Here is the video. The video quality seems to have suffered on its journey from PC to youTube. I was aiming for under 7 mins but it grew to nearly 10.




Here is how I would do it in a mill. Virtually zero setup, just add some G-code and away you go. click on pic. for full size.

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Y-geo (Aug 17, 2017)

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## tonyfoale

> Ralph,
> Tool post pivoted ball / ogive turner in close up action :-



There many similar examples of this on the net but they have missed an opportunity. 
They have placed the rotational axis of the tool assembly on the centre line of the cross slide, just like mine. That was forced on me because of my decision to use the existing compound rest as the basis. However, it would have been very easy when building the complete thing from scratch to move the axis on the plate forward toward the chuck. maybe even overlapping the edge of the cross slide with the plate. So those designs suffer needlessly from the same problem as mine, they both need a lot of work piece overhang to provide clearance from the chuck. 
Another aspect which could be easily improved is the tool holder. There is no need to machine the guts out of it to make an "L", If just enough is machined away to provide clearance for the largest ball then it would be more rigid and have more mass. Rigidity and mass are very desirable properties on any machine tool.

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Toolmaker51 (Aug 20, 2017),

Y-geo (Aug 18, 2017)

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## Ralphxyz

Thanks Tony, I sure hope I can find this thread when I get around to actually making a ball turner.
I am actually working on closing up the space in my shop to receive my Craftsman 12x36 lathe which has been sitting outside my shop in a crate for the last 8 months waiting for me to finish that section of my shop.

My todo list keeps getting bigger and I seem to keep getting slower, must be that dam AGE virus that is going around.

Still not fully grasping the geometry but I think when I am at my lathe it will sink in.

If it is this simple why does anyone build the more complicated ball turner?

Thanks for the video that really helps.

Ralph

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## Ralphxyz

Thanks Tony, I sure hope I can find this thread when I get around to actually making a ball turner.
I am actually working on closing up the space in my shop to receive my Craftsman 12x36 lathe which has been sitting outside my shop in a crate for the last 8 months waiting for me to finish that section of my shop.

My todo list keeps getting bigger and I seem to keep getting slower, must be that dam AGE virus that is going around.

Still not fully grasping the geometry but I think when I am at my lathe it will sink in.

If it is this simple why does anyone build the more complicated ball turner?

Thanks for the video that really helps.

Sorry if this gets duplicated the forum software is messing with me.

Ralph

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## tonyfoale

> If it is this simple why does anyone build the more complicated ball turner?



Ha, I often ask myself that about a lot of things. I am lazy so I tend to find simple solutions. In this case my solution is perfect for my stated and immediate need but it is in general not as flexible in application as some of the purpose built versions. I was constricted by the pivot being set back from the edge and so chuck clearance is a problem to such an extent that I can't do much in the way of small concave shapes. Big ones will be fine.

As to finding the post again, you only have to search the forum archives for a phrase like "ball turner" or else search for topics under my name, then you will get all of my offerings.

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## Wmrra13

Thanks Tony!

BTW, is that a Bultaco or an MV in your Avatar? 
I used to race a liquid cooled 350 TSS years ago.

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## tonyfoale

> Thanks Tony!
> 
> BTW, is that a Bultaco or an MV in your Avatar? 
> I used to race a liquid cooled 350 TSS years ago.



Neither, it is an Aermacchi 350 in my chassis. I raced one in the early 1970s and now I race a copy of my original. There is more info in the Aermacchi folders at
https://get.google.com/albumarchive/...99061223276003

  Click for full size
Original and current.

I rode an aircooled TSS 350 in my first visit to the island. I lived in Australia and the boat bringing my 'macchi over had engine trouble in mid ocean and the bike didn't arrive in time. Geoff Monty lent me the Bultaco at the last moment. Here it is at Ballaugh.

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olderdan (Mar 9, 2018)

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## old_toolmaker

Nice job, Tony! Gets the job done.

I made an over the top ball turner that uses a 2" Criterion boring head mounted in a QC tool post. Works great and I don't have the overhang issues you mentioned.

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## tonyfoale

> Nice job, Tony! Gets the job done.
> 
> I made an over the top ball turner that uses a 2" Criterion boring head mounted in a QC tool post. Works great and I don't have the overhang issues you mentioned.



The boring head ball turners are a nice practical way of doing the job. Much better than many of the designs out there on the web. With the boring head versions you get the fine diameter control that I get with mine.

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## steamingbill

> Nice job, Tony! Gets the job done.
> 
> I made an over the top ball turner that uses a 2" Criterion boring head mounted in a QC tool post. Works great and I don't have the overhang issues you mentioned.



Hello Dick,

I made a boring bar ball cutter but dont seem to be able to get the tool grind correct, seem to get a lot of chatter.

Any tips ?

Bill

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## tonyfoale

> Hello Dick,
> 
> I made a boring bar ball cutter but dont seem to be able to get the tool grind correct, seem to get a lot of chatter.
> 
> Any tips ?
> 
> Bill



Many ball turners lack rigidity. Of course I can not speak for yours, maybe if you post a photo of it we can give an opinion.

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## Wmrra13

> Neither, it is an Aermacchi 350 in my chassis. I raced one in the early 1970s and now I race a copy of my original. There is more info in the Aermacchi folders at
> https://get.google.com/albumarchive/...99061223276003
> 
> Attachment 22557 Attachment 22558 Click for full size
> Original and current.
> 
> I rode an aircooled TSS 350 in my first visit to the island. I lived in Australia and the boat bringing my 'macchi over had engine trouble in mid ocean and the bike didn't arrive in time. Geoff Monty lent me the Bultaco at the last moment. Here it is at Ballaugh.
> 
> Attachment 22559



That's such a great pic from IoM Tony!

I'm presently traveling and don't have access to any photos from my Bultaco days in the mid '90s. That bike was really a treat and a privilege to ride, we had some great days at the track but we also broke a LOT of parts and watched some races from the pits.

It's ironic that your '74 bike had a monoshock and disc brakes but the "modern" version is a twin shock with a drum up front. You were ahead of your time in '74. Now, 44 years later you can't do the same things you were doing back then and be "period legal" 

Sorry for the motorcycle related topic detour....

Cheers,
Tyler

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## old_toolmaker

steamingbill,

The boring tool I used is sharpened in a different manner than a normal boring tool used in a boring head or lathe. The cutting edge that is normally sharp has a radius along it's edge of about .030". The end of the bar is the equivalent of the top surface of a lathe tool and is the cutting edge. It is hard to explain. I have posted a picture of the tool set up in the lathe. And finally a picture of the batch of ball handles I produced with this set up for use on my Quorn tool and cutter grinder.

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steamingbill (Jun 6, 2021),

Toolmaker51 (Mar 10, 2018),

Wmrra13 (Mar 7, 2018)

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## Ralphxyz

I need to see the tool on the inside of the ball (towards the headstock). I do not see how you rotate the tool; to get the ball.

Nice work by the way, I cannot wait until I am able to do something similar.

Ralph

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## Wmrra13

> steamingbill,
> 
> The boring tool I used is sharpened in a different manner than a normal boring tool used in a boring head or lathe. The cutting edge that is normally sharp has a radius along it's edge of about .030". The end of the bar is the equivalent of the top surface of a lathe tool and is the cutting edge. It is hard to explain. I have posted a picture of the tool set up in the lathe. And finally a picture of the batch of ball handles I produced with this set up for use on my Quorn tool and cutter grinder.



That's a really nice set-up Dick! I may try to build one of those.
What type of bearing are you using in the big square block? 

Bonus points for showing that great batch of handles you made and the ball turning tool still has a big red plastic ball!

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## old_toolmaker

Hi Ralphxyz,

I do not have that job setup so can't take a picture. That job was done over 10 years ago. The tool is on center front to back and is ground flat on the end. Take a good look at the operator end of the attachment and you will see a handle with a red knob and that is how it is rotated. Also you will be able to see two stops and a pin sticking out the operator end. That is how the arc of rotation is limited to get repeatable results on each successive part.

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## old_toolmaker

Wmrra13,

Thanks for the complement! The bearing is a standard 1" I.D. oilite bronze bushing and does the job nicely. Yes, it has a big red plastic ball on the end of the handle. Shame on me. I should have taken the time to do it right on that tool but I was in a hurry and had the ball on hand so I used it. I never thought anyone would ever see it.

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## tonyfoale

> steamingbill,
> 
> The boring tool I used is sharpened in a different manner than a normal boring tool used in a boring head or lathe. The cutting edge that is normally sharp has a radius along it's edge of about .030". The end of the bar is the equivalent of the top surface of a lathe tool and is the cutting edge. It is hard to explain. I have posted a picture of the tool set up in the lathe.



That certainly looks rigid enough. Assuming that the cutting edge has suitable clearance and rake angles the only thing that comes to mind re your chatter problem is that maybe the rotation is too free. Some damping or friction in the rotation might well reduce the vibrations that are associated with chatter. Try making it stiff but smooth to rotate.

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## old_toolmaker

Hi Tony,

Could you possibly have me confused with someone else? I have not had chatter issues with my over the top ball turning attachment. I think it was the original poster who was having problems.

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## tonyfoale

> Hi Tony,
> 
> Could you possibly have me confused with someone else? I have not had chatter issues with my over the top ball turning attachment. I think it was the original poster who was having problems.



Oops sorry about that. As I was the original poster I know it wasn't me. It was steamingbill who had chatter and I asked him to post a photo of his and when I saw your photo soon afterwards I wrongly assumed it was you. Aw well, no harm done.

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## olderdan

Tony 
tThanks for posting that link https://get.google.com/albumarchive/...99061223276003 there is some real interesting stuff there. I think we are of a similar age as I remember some of those press pages from my early twenties onwards, my favorite mag was Motorcycle Sport (which I still have a stack of) as they would contain more in depth technical articles. I have found alternative designs fascinating but lacked the technical ability to anything more than observe.

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## tonyfoale

It looks like I have accidentally deleted video files from my Dropbox, and so the video link for this post was broken.
I am working through putting these videos up on Youtube where they should be safe. Here is the link for this one.

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## old_toolmaker

I use a 2 Criterion boring head for up and over ball turning. Micrometer adjustment is indispensable when turning ball precision ball shapes. I have adjustable stops on both ends of travel.

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