Furyous
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| posted on 16/8/12 at 09:19 AM |
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Turning a radius on a lathe
I've been getting the hang of my lathe and I've already made about $700 worth of tools for work in just a few weeks, with huge
improvements over some of the old tools we were using.
Something I would like to improve on is turning a smooth radius. The tools I'm making are a cup to hold the base of a bottle steady. At the
moment I'm either using a right angle base or guessing a rough slope near the shape of the bottle base. Ideally it would match the radius of the
edge of the bottle base. I can't seem to find much online other than some home made looking rotating tools to replace the fixed tool post. Ebay
just has a couple of tools available from America with shipping three times the cost of the item.
Am I missing something or are the things I'm looking for really that uncommon?
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daviep
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| posted on 16/8/12 at 09:38 AM |
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Is it not possible to grind a tool to the correct radius?
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
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liam.mccaffrey
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| posted on 16/8/12 at 09:56 AM |
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I have one of linky for sale. You could extend the
cutting tool out past the pivot point and cut internal rads. I havn't tried this though!!
Also Hemingway sell this kit.
linky
You might be better with a form radius cutter for very small rads though.
[Edited on 16/8/12 by liam.mccaffrey]
Build Blog
Build Photo Album
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robocog
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| posted on 16/8/12 at 10:02 AM |
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Ball turning tool
http://bedair.org/Ball/ball.html
http://www.machinistblog.com/free-plans-ball-turning-tool-post-for-the-7x-mini-lathe/
Cutting tool can be reversed to make a cup / socket turning tool
Looks simple enough to make and use ....I have been meaning to make one for a few years but not got 'round' to it yet...LOL
Dividedheads fab vids showing them in use....
http://www.youtube.com/watch?v=tbvOb-tTNyc&feature=channel&list=UL
http://www.youtube.com/watch?v=s_KRElCauTM&feature=related
Regards
Rob
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mad4x4
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| posted on 16/8/12 at 11:58 AM |
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What about this - Build yourself one
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
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40inches
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| posted on 16/8/12 at 02:06 PM |
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quote:
Originally posted by daviep
Is it not possible to grind a tool to the correct radius?
Cheers
Davie
That's what I did, doesn't take long.
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mcerd1
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| posted on 16/8/12 at 02:55 PM |
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quote:
Originally posted by 40inches
quote:
Originally posted by daviep
Is it not possible to grind a tool to the correct radius?
Cheers
Davie
That's what I did, doesn't take long.
thats what I've always done too, but the links above have got me thinking about building a new tool..... 
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owelly
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| posted on 16/8/12 at 03:40 PM |
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I've often turned stuff using a pointer mounted in the back of the tool post, running on a profiled template. A bit like a key cutting machine.
With a bit of patience, it works very well and certainly better than free hand!!
http://www.ppcmag.co.uk
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theprisioner
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| posted on 16/8/12 at 06:14 PM |
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Myford CNC
Just some stepper motors + software
http://youtu.be/JvU0Uo-ntZw
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Furyous
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| posted on 16/8/12 at 06:46 PM |
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Thanks for the replies.
The trouble with the home made ball turning tool is I would need a mill to cut the slot in the centre, which I don't have.
I'm currently using cutting tools with replaceable tips but I could try grinding my own tools. The problem with that is I would spend a lot of
time grinding a cutting tool that would only be suitable for one type of bottle/cup. The rotating tool post type seems like it would be easier to
adjust for different jobs. But then I wouldn't be able to turn it very deep in the cup before it hits the rim of the cup.
I'll have a go at grinding some cutting tools.
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907
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| posted on 16/8/12 at 09:32 PM |
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I made this.
Just a brake clevis and a cap head screw with a grub screw inside the head to hold a tool.
Paul G
 
Description
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daviep
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| posted on 16/8/12 at 10:06 PM |
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quote:
Originally posted by Furyous
Thanks for the replies.
The trouble with the home made ball turning tool is I would need a mill to cut the slot in the centre, which I don't have.
I'm currently using cutting tools with replaceable tips but I could try grinding my own tools. The problem with that is I would spend a lot of
time grinding a cutting tool that would only be suitable for one type of bottle/cup. The rotating tool post type seems like it would be easier to
adjust for different jobs. But then I wouldn't be able to turn it very deep in the cup before it hits the rim of the cup.
I'll have a go at grinding some cutting tools.
I would never claim to be able to grind tools "properly" but it's very easy to grind them to an adequate standard.
Do you have coolant on your lathe? If not then something to watch if you are self taught and always used carbide tipped tools is that HSS will not
tolerate being run too fast - instant bluntness, a lesson I'm still learning (or not as the case may be)
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
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Furyous
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| posted on 17/8/12 at 04:53 AM |
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quote:
Originally posted by 907
I made this.
Just a brake clevis and a cap head screw with a grub screw inside the head to hold a tool.
Paul G
Description
That looks like something I could cobble together myself.  It's also small enough to get inside the cup. I just need to find some clevises
somewhere.
Grinding my own tools would probably be cheaper than replaceable tips in the long run anyway.
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907
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| posted on 17/8/12 at 06:06 AM |
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quote:
Originally posted by Furyous
quote:
Originally posted by 907
I made this.
Just a brake clevis and a cap head screw with a grub screw inside the head to hold a tool.
Paul G
Description
That looks like something I could cobble together myself. It's also small enough to get inside the cup. I just need to find some clevises
somewhere.
Grinding my own tools would probably be cheaper than replaceable tips in the long run anyway.
Ebay? or a trailer spares site?
eBay Item
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Furyous
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| posted on 17/8/12 at 06:15 AM |
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I'm in New Zealand so it's not as easy as going to eBay. We have TradeMe here, which is like eBay in 1998. I'm not all that
familiar with local shops so I'll have to look around for them but I'm sure they're available.
On a related note, apparently a C spanner is a specialist item and very few places sell them here. I still haven't found anyone that actually
sells them.
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mcerd1
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| posted on 17/8/12 at 07:12 AM |
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sounds like your going to need to find someone over there with a milling machine and/or a waterjet cutter to make all the tools you need
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907
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| posted on 17/8/12 at 07:35 AM |
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quote:
Originally posted by Furyous
I'm in New Zealand so it's not as easy as going to eBay. We have TradeMe here, which is like eBay in 1998. I'm not all that
familiar with local shops so I'll have to look around for them but I'm sure they're available.
On a related note, apparently a C spanner is a specialist item and very few places sell them here. I still haven't found anyone that actually
sells them.
You could put an end milling tool in the 3 jaw chuck and the square bar in the tool post
and mill the slot straight into the bar.
You wanted to play with your lathe.
In the past I've made end cutting tools from the shaft of a broken tap.
(never throw a broken tap away)
Paul G
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