Anyone recommend a ball/radius turning tool for clarke CL430 lathe?

HI folks,

I need to machine a 15mm rad on some hardwood I'm using as a tool to spin form some 1mm ali on. It's making an ali fan cowl.

I've seen a number of people use router bits and milling cutters held in the tool post.

While cheap and good enough, I'm intending to make cowls of other dimensions, and the cost of bits/cutters can overtake the cost of a radius turning attachment.

Bear in mind, some of the wooden blanks I'm using are about 5-6" OD and I work the leading edge, so the postion of the tool with respect to the place the tool post can reach will be an issue. Using bits are easier in this case.

So, can anyone recommend a suitable attachment for the CL430?

Regards

If you can't find anything, Marv Klotz's 'ballcut' ball turning program can be useful, second program down here: **LINK** The programs there are all in DOS. I did a windows implementation of Marv's DOS program here: **LINK**

The program can be used on any machine that has a parting tool. I use a Warco WMT300/1, which is the Warco version of the CL500. The reason I included a 'Longitudinal Origin' & 'Cross Feed Origin' in my program is that, unlike the CL430, the Warco has its division dials keyed to the leadscrews.

Regards,

Richard.

Hi Richard,

Thanks for your reply.

By tool, you probably mean software tool? I was hoping for a mechanical device I could bolt onto my lathe like the tools you see on ebay.

Thanks

Lash up a tool rest from a piece of bar in the toolpost and hand turn it using a wood chisel.

regards Martin

A simple radius turning tool can be as a simple as a pivoting plate fixed to the cross-slide with an upright bar with a simple tool mounting on top and a long handle.

The Steve Bedair ball turning too discussed recently in this thread is worth considering. I have built one and it works well.

Les.

Hi Neil,

I like the idea - whats the best way to form the section to hold CCMT inserts (as I have a bunch of these)?

I bought a tool called the "repton radius turning tool" which seems to work satisfactorily, I did have to grind a hard edge of the mount so that I could swivel it the whole way round without fouling.

The tool uses a 30 degree or so carbide insert. The main benefit of it is you can accurately measure the size of the radius produced by using a ruler to see how far past the pivot point for either concave or convex.

All in all I would say it's well made, easily fits into a Dickson type adjustable tool holder and easy to master. However, for a very large radius then perhaps I would be better off to make a custom setup like Neil described above.

Michael W

I've seen those repton units and have thought about buying one, the question is, would it fit a stock CL430 lathe without a QCTP?

I did ask a supplier on ebay about suitability, and I got a "yeah sorta fits those lathes". don't really have the time to buy,try, tinker and return.

I've got a Clarke too, AeroJet and you can probably measure whether it will fit, in my mind, I can picture that It will, but I know the shank of the repton is 10mm square.

The only difficulty you'd have is to adjust the centre height of the tool using shims to fit. In this particular circumstance i'd say you'd be likely needing to make your own radius turning tool from a design or pattern.

It wouldn't be too hard to modify a repton radius tool with a bit of creativity of reducing the shank size a bit since all of it is made from aluminium it's pretty easy to cut and re shape.

Michael W

Points considered, I'll see what material I have to quickly put something together, if it gets too fiddly I'll buy the repton unit.

Thanks All for the advice!

Sounds like my yet-to-be patented Ruff-E-Nuff ball turning tool put together from workshop scrap. Radius is varied by moving the HSS tool bit. Looks ruff-e-nuff but has made some beautiful ball handles ranging from 1" long to 4" long for various projects such as the GHT dividing head and 4-way toolpost.

All the above radius turning attachments work but just think of the scale for your 5"and 6" size ! It is but simple maths to work out a series of steps and blend in by hand. I have done this on steel mould tools sometimes using the maths to work out an angle and blend some more of the metal away.

got the repton to use on my 430 had no probs

For very large radii all you need is a fixed pin on the cross slide and another on the bed. Drop on a link of the correct length and feeding the cross slide in will draw the saddle towards the work and generate the curve. Only works for curves somewhat less than 140 ish degrees due to the geometry.

regards Martin

Copy an existing tool holder. I recently saw one where someone had used two screwed-on buttons instead of milling a pocket.

Neil

The Repton is useable on a lathe the size of a Warco BH600, (Clones are Chester Craftsman or Engineers ToolRoom BL12/24)

It uses diamond shaped 55 degree inserts.

It works well on all the jobs for which it has been used so far.

Mine is fixed to an adaptor in the 4 way toolpost. Had to bend the rod used as a handle, to clear the clamp lever on the toolpost.

Had a job making head or tail of the instructions, so made up an adaptor so that it can be centered using one of those V shaped gadgets for centering work under the Mill/Drill.

Seemed expensive, but is a well finished tool which does what is required of it.

Howard

Edited By Howard Lewis on 13/05/2017 17:21:39