Ball Turner

[Stot]

Hi,

I have a few projects floating through my head and some are on paper now like a 1:16 scale Flak AA gun  , but Ive decided the for my first project i should make a ball turning tool so a couple of Qs.

I see most people have used what they have laying around to make their ball turning tools ( Steve Bedair type ), but there is always aluminum in there somewhere.

Sooo assuming the bit mounting 'L' piece would be 15mm square steel in my design, can I make the base plate and rotating column from aluminium, or should I aim for cast iron/steel for rigidity?

Also has anyone run their ball turning tools on bearings?  My one would be fairly large with a 3" diameter turret allowing a 3+" radius to be turned so I thought adding an old wheel bearing between the base and the turret would help keep things tight but smooth.

Lastly, Assuming i'm talking a 4.5" x 5/8" disc for the base and a 3" x 1.5", where is a good source for big ol lumps of solid cast iron like this if I do want to build it from cast iron?  UK i guess.    I could probably find old barbell weights for the 4.5" one.. 

Any opinions appreciated.

Cheers
Stot

[Bernd]

Imade mine all out of aluminum for the Grizzly lathe. Only turned two balls with it. Worked OK.

I think a ball bearing would surely make it turn smoother.

Can't help you on the last question. 

Bernd

[Stot]

Thanks for the reply, I'm looking to turn a lot of stainless steel balls for example, so im not sure aluminium will be up to it for too long .

If I do incorporate a tapered roller bearing between the turret and plate I may use an old valve spring as a tensioner on the through bolt.    Could work.  

Oh yeah, Also i found a company selling cast iron backplate blanks for £15 which have a core diameter that will work nicley.   

Cheers
Stot

[Divided he ad]

Evening Stot     I'm going to throw a few pennies in here and see if it helps??


I'm assuming you have done a search of the site for "ball turner"? (in the "   " marks.)

This turns up all sorts of designs and re-designs on the ball turners used by members of the site (including me)


I've made 2 of them and both using steel to steel design. I've cut a lot of stainless using the larger one I built (the mini one has a new home).

I've had no problems using mine to cut hundreds of shaped bits 'n' bobs in stainless, brass, bronze, aluminium and just about any metal I could get my hands on. I've posted a lot of pic's and videos in the gallery and other areas of the site.




Just a thought, The diameter of the turret (3") allows for a lot of lateral movement of the cutter section, but how tall are you making the cutter (using the 15mm square)?

I know this might sound obvious but, the height of the tip from the turret would have to be just over 3" to enable the cutter to reach it's maximum "safe" radius size of 3".... A 6" solid metal sphere    Now that would take some turning!!!   

(IMHO "safe" being... the "L" clamped in half of the slot it slides in)


I'm also going to assume that the 5/8 base depth and the 1.5" turret depth are what you have worked out to bring the tip holder closer to centre height and keep the rigidity in the tool?  (this would have to still be just over 3" to obtain optimal tool use).


These are just my thoughts..... I know I ramble a bit!


As for the use of aluminium. I would think that it would need a lot of lubricating and a much larger contact surface with the base than steel would to spread the cutting forces and prevent premature wear.... Just my thoughts.

Cast iron might be a bit odd to use too? It's a little brittle IMHO and may also need a larger contact area to prevent stresses from cracking/chipping the turret?

Steel is IMHO the way to go.


Of course when you add bearings to the mix it all alters.... I have not had to go to this extreme as my ball turner works a treat 



I hope some of that makes sense,   








Ralph.

[Stot]

Hi Ralph,

Evening Stot     I'm going to throw a few pennies in here and see if it helps??

I'm assuming you have done a search of the site for "ball turner"? (in the "   " marks.)

This turns up all sorts of designs and re-designs on the ball turners used by members of the site (including me)

I've made 2 of them and both using steel to steel design. I've cut a lot of stainless using the larger one I built (the mini one has a new home).

I've had no problems using mine to cut hundreds of shaped bits 'n' bobs in stainless, brass, bronze, aluminium and just about any metal I could get my hands on. I've posted a lot of pic's and videos in the gallery and other areas of the site.

Yes i did lots of searching and reading and seen your vids.

Just a thought, The diameter of the turret (3") allows for a lot of lateral movement of the cutter section, but how tall are you making the cutter (using the 15mm square)?

I know this might sound obvious but, the height of the tip from the turret would have to be just over 3" to enable the cutter to reach it's maximum "safe" radius size of 3".... A 6" solid metal sphere    Now that would take some turning!!!  

(IMHO "safe" being... the "L" clamped in half of the slot it slides in)

I'm also going to assume that the 5/8 base depth and the 1.5" turret depth are what you have worked out to bring the tip holder closer to centre height and keep the rigidity in the tool?  (this would have to still be just over 3" to obtain optimal tool use).

Ah did I say radius?  I meant a 3" diameter ball.



This is the modified design for my center height with a VCGT type bit on top.    So the max overhang of the L piece would be ~15mm allowing it to be clamped by 2 of the retaining bolts, or I can make the sliding piece longer to make sure its clamped by all 3 when at max cutting diameter.  The height of the tool tip on the upright of the L piece would be 40mm.

These are just my thoughts..... I know I ramble a bit!

As for the use of aluminium. I would think that it would need a lot of lubricating and a much larger contact surface with the base than steel would to spread the cutting forces and prevent premature wear.... Just my thoughts.

Cast iron might be a bit odd to use too? It's a little brittle IMHO and may also need a larger contact area to prevent stresses from cracking/chipping the turret?

Steel is IMHO the way to go.

Of course when you add bearings to the mix it all alters.... I have not had to go to this extreme as my ball turner works a treat  

I hope some of that makes sense,    

Ralph.

I figure if I only want to build one ball turning tool, build it as big as is reasonable for my lathe, and as well as I can to have it last a lifetime.

I get what you mean about the cast iron maybe being to brittle, it could crack as i tighten down the sliding post.   So now to search out some 3" steel round bar then!  

Cheers
Stot

[Jasonb]

I made mine all from steel with a 1/2" base and 2 1/2"dia body. Any of the model engineering metal suppliers will sell that sort of dia stock by the inch, if you are able to attend any of the shows then they usually have plenty of offcuts. I've not found the need for a bearing, just some grease and a bellview washser seem to work fine. This is mine in action

If you need to order the metal then try these - College Engineering, EKP Supplies, Mallard Metals, Macc Model Engineers Supplies

Jason

[Stot]

I made mine all from steel with a 1/2" base and 2 1/2"dia body. Any of the model engineering metal suppliers will sell that sort of dia stock by the inch, if you are able to attend any of the shows then they usually have plenty of offcuts. I've not found the need for a bearing, just some grease and a bellview washser seem to work fine. This is mine in action

If you need to order the metal then try these - College Engineering, EKP Supplies, Mallard Metals, Macc Model Engineers Supplies

Jason

Thanks Jason,  first search for College Engineering and they have 3" steel at £2.55/1"    perfik

Cheers
Stot

[Divided he ad]

Hi again....

Just read this,

with a VCGT type bit on top

And thought to myself.... You really should sink the tip into the steel "L" piece.  If you mount it on top the screw alone probably won't have the strength to pin the tip down and it'll start to spin as you cut 

I used a slot drill (large enough to allow the tip sides fit in) to make a hole to the correct depth then a small endmill to clear the material from the sides. (I suppose some steady handed dremel work could do the sides too?  )

Found this when looking for the code of the tips.... Quite useful I thought     http://www.iscar.com/ProductLines/Pdf/VCGT_CCGT.pdf  .


What height will be between the turret top and the cutting tip surface? cause this is what controls your maximum radius/cutting ability.
If you make the lower part of the "L" long enough to still be clamped when it is set to the same distance as the answer to the above question then you will not need your clamped part any longer.
If you make it too long it'll probably contact the chuck and or it's jaws...... That is quite scary.  (there isn't a smiley for what I did!!!)


If any of what I'm saying doesn't make sense just say    (I'm not saying you won't understand it.... More that I do write some right carp now and again  )


From the look of the drawing you've already figured out not to drill through the turret, this is essential to the set up of the metal to metal version of this tool 




Have fun, make sure you show us some build pic's in the project logs section 









Ralph.

[Darren]

I read somewhere that if you screw the insert down and mig weld around it that you can form the inset seat. Apparently mig welding heat won't affect the carbide or stick to it.

I've not tried it so take the info with a pinch of salt till the theory has been proven 

[Stot]

The tip of the tool will be 40mm above the turret.  so an ~80mm ball is possible.  The L piece would then be held with 2 of the holding screws, which will probably be fine.

I thought about needing an inset for the bit too,  Ive only got an arc welder but i could give it a shot with an old dull bit and see what happens. ;)

Ill definitively figure out something to hold it in place.    Thanks guys.

Cheers
Stot

[Divided he ad]

Never heard that one Darren    Sounds interesting though. Haven't got the MIG to test the theory though 


Stot,
2 screws will hold fine in my experience. (1 screw does let go.... Got the T-shirt    )


an 80mm ball is huge.... Cool!      (brass walking stick top/kosh?           )


Looking forward to the progress pic's   









Ralph.

[Stot]

Well Ive ordered the metal from Macc, great price from them and had all the sizes I needed, Thanks for the heads up Jason, all steel and have decided on no bearing. I figure some moly paste on the steel will do the job nicely without introducing as much wear related slop, and the grease/paste can be re-applied during maintenance.

Im after as big a radius as possible so I can get some sweeping curves rather than make huge balls.    but I may have to make a couple just coz I can... 

Ill take a ton of pics and post up my plans over the weekend ( as long as the metal turns up this week ) as I try and make it.   

Cheers
Stot

[Gerhard Olivier]

Hi - you will enjoy the ball turner with or without the bearing.

I did the bearing as a improvement after making the BT  http://madmodder.net/index.php?topic=1822.0

I would advise that it is definitely not neccesary but it makes the BT so much nicer to use.
Main thing I wanted to say was if there is any chance that you want a bearing - do it from the start -as it is more difficult to do afterwards.

Gerhard

[No1_sonuk]

One thing you should check before you start is the mounting point location and cross slide travel.

While I was planning mine, I came across a few designs that have the rotation axis of the turret concentric with the cross slide mount point.  However, when I checked on my machine (a Chester DB7VS), I found that the mount point axis wouldn't line up with the spindle axis before the cross slide came off its lead screw.

The up-shot is that I needed to use one of the "turret on a plate" designs to gain the required offset.

I used all-aluminium for mine, including the tool holder, and VBMT tips (idea blatently stolen borrowed from Ralph, I think ).  This was primarily as I needed it quickly and had suitable sizes in stock.  If it becomes necessary, I'll replace parts as required.

[Divided he ad]

(idea blatently stolen borrowed from Ralph, I think  )

It's all here to share, hopefully inspire and be blatantly borrowed      




I hope all that metal has arrived? 



Have a good weekend Stot   






Ralph.

[Stot]

Still waiting.    They were waiting for some 5" round bar to come in, it didnt turn up and they are on hols next week so they sent it without now so ive ordered a piece of 6" from College Engineering. 

Hopefully next week then.. 

Cheers
Stot