# lathe radius cutter



## benni

Does any one have ideas for a radius cutter?


----------



## JPigg55

Not sure if you're looking to buy or make one or what size, but here's a site where a guy made one.
http://www.pirate4x4.com/forum/shop-tools/741444-homemade-radius-cutter.html
Show material list, has lots of pictures, and some youtube videos.
Hope this helps.


----------



## GK1918

Not sure of your quest, but this is how I do it.


----------



## Bill Gruby

I'm not quite sure either. Do you wish to know how to grind a cutter for a specific radius or are you looking for a Ball turning attachment?

"Billy G" :thinking:


----------



## autonoz

http://bedair.org/Ball/ball1.html

I am currently making this one, if that is what you are looking to do.


----------



## Mike Gibson

Here is a really good one made and drawn by Dick Kostelnicek of the Home Metal Shop Club in Houston, Tx.
Mike
http://www.homemetalshopclub.org/news/10/newsletter1004.pdf#Page=4


----------



## darkzero

autonoz said:


> http://bedair.org/Ball/ball1.html
> 
> I am currently making this one, if that is what you are looking to do.



Mine is based on Steve Bedair's design. Works great but it has capacity limitations. I did not make mine 100%, I bought a premade unit for a Myford lathe & adapted to fit my lathe. I did not have a mill at the time so this was my only option then. I don't use it often but when I'm able to I'm glad.

Here's a cut & paste that I have posted on another forum:




darkzero said:


> Ever since I got my first mini lathe I've always wanted a ball turning attachment. So I decided to make one for my current lathe. Since I don't have a mill yet, I used an attachment that I got from the for a Myford that is based on Steve Bedair's ball turning tool post.
> 
> Here's how I did it (...lots of pics to follow!).
> 
> 
> Here's what I started off with. The Myford attachment & a 5" dia 30lb piece of CR1018.
> 
> 
> 
> 
> Mounted in the 4 jaw, making the base plate with this piece.
> 
> 
> 
> 
> Cut off the base plate & save the rest for another project.
> 
> 
> 
> 
> Cleaned it up, drilled a couple of holes, & test fit.
> 
> 
> 
> 
> 
> 
> 
> Bored out the recesses on the top of the base plate for the tool post.
> 
> 
> 
> 
> Bored out the bottom of the base plate for the mounting/pivot screw.
> 
> 
> 
> 
> Base plate is done, on to make the post assy. 3" dia 1018.
> 
> 
> 
> 
> 
> 
> 
> Machined the steps for the bottom of the tool post.
> 
> 
> 
> 
> Bored out the recesses on the top off the tool post for the cutter assy. Drilled a hole all the way through for a M6 bolt, then tapped threads the bottom for a M10 bolt.
> 
> 
> 
> 
> Tool post is done, time for a test fit.
> 
> 
> 
> 
> Tested it out on a piece of alum. Ditched the insert & screw that it came with for a TNMG 331 Cermet insert & Ti flathead/countersunk type screw for better seating. Chatter free & right on center line!
> 
> 
> 
> 
> Here's how I measured the cutter height.
> 
> 
> 
> 
> Here is the top mating surface for the cutter assy.
> 
> 
> 
> 
> Turned down a M6 bolt to fit through the M10 thread at the bottom of the tool post to bolt on the cutter assy.
> 
> 
> 
> 
> The mating surfaces of the post & base plate. Since this is where I made the tool post pivot I added some lube.
> 
> 
> 
> 
> The bottom of the base plate. This part is critical since the washer should only mate against the small step of the post that fits through the base plate. But if that step is too high you'll get unwanted play leading to chatter.
> 
> 
> 
> 
> 
> 
> 
> All assembled.
> 
> 
> 
> 
> Time to give it a try, first up was a ball knob to replace the cheapo plastic one.
> 
> 
> Threaded a rod & a piece of steel.
> 
> 
> 
> 
> The rod I was using to hold the stock was too thin & chattered a lot so I had to switch to a thicker one. After a little bit of sanding I ended up with this.
> 
> 
> 
> 
> Here's the new knob on the tool post.
> 
> 
> 
> 
> 
> Thanks for looking.


----------



## darkzero

Here's what I made with it...


Titanium Tippe Tops

























[video=youtube;GHs2ft9_Ado]http://www.youtube.com/watch?v=GHs2ft9_Ado[/video]


----------



## darkzero

Oh & here are some other's that I am considering, the boring head version first now that I have a mill to make to cutter.

http://www.statecollegecentral.com/metallathe/MLA-13.html

http://thebloughs.net/hobbies/metalworking/ball_turner/index.php


----------



## aametalmaster

benni said:


> Does any one have ideas for a radius cutter?



Yup...Bob
http://www.hobby-machinist.com/album.php?albumid=142


----------



## ML_Woy

How did you pick the carbide insert to use given the hundreds there are out their to choose from? I am building a tool myself and am confused as to what insert to use. I want one that will set flat but from there I am lost.


----------

