Radius Turning Options

Can anyone suggest accessory options for turning a concave radius into the side of a cylindrical part on a Hardinge HLV-H?

I know Hardinge makes a dedicated accessory for this, but they are quite costly on the used market, and I'm sure the new price (if it is even listed) is a not-in-stock-special-order "don't bother us with this" type price.

I only need to turn a small concave radius in an aluminum part. Part diameter is about 1" and radius about 0.75".

Thanks for your suggestions.

I made this simple device to cut some pipe formers :

just a block that holds a couple of bearings and a right angle bracket . Tool is a broken end mill inserted trough a piece of bar.

I have some Hardinge radius attachments but seldom use them. I often find it quicker to grind a form tool and plunge it in for a job like making pulley grooves for round belts. If the radius is not critical or the shape is not a simple radius, I use a hand-held tool and a T-rest. Think wood-turning technique and wood-turning tools, either HSS or carbide. Works on metal just as well as wood or plastic.

You might find a used Shaplane tool on eBay. They come in outside and inside versions.
Eagle Rock Shaplane Radius Tools - 24806 - Penn Tool Co., Inc

Larry

If you see this as a repeated need, a Holdridge radii cutter is another option and a bit more versatile than a single Shaplane cutter. Maybe $400 used for a 3D or 4D size? As Bill and Larry have said, you can either make a cutter or do it free hand for this job.

Thanks for the tips! I will be looking into those tools.

My previous setup worked well but was greatly overcomplicated and took forever to set up (see photo below). It was a custom radius cutter holder held in a Sherline 8700 CNC rotary table, sitting on a Sherline linear slide, bolted to the side T-slot of my Schaublin 102N.

The main advantage was that once it was set up, the stepper motor could move in arcs, and it was like a power feed for the radius turning.

The part being cut is a sprocket roller from a 16mm film camera (with the steel sprocket teeth removed). It is being cut to make it compatible with a newer 16mm format that uses a wider image area.

I last cut these rollers in 2009 and converted one camera (using up 4 rollers). I got zero demand for them until this year. Now I've used up all my converted rollers and it may make sense to make up some more (converting the rollers removed when the converted ones are installed).

It seems than once things become unavailable and remain so for a while, people start wanting them again!

A Sherline on a Schaublin! I can see certain people here passing out from the shock.

There are so many ways to skin this cat. All the ways so far are good a couple more or to plot the locations every couple of degrees and plunge in with a smaller radius tool. The file and sand smooth. Guy Lautard has a book here he describes how to do it with charts. Anymore when I do it I just make a CAD drawing then plot the points. Another way would be to trace it with a dial indicator. Works well on pipe tapers no reason it would not work on a concave radius on the OD. The attached photo is a mock up on a South Bend but you will get the idea. In practice I did it with the taper gauge on the back side of the tool turret. On an HLV-H the template could be held on the cross slide with some of the available tapped holes already there.

I would think any indexer would work for that.

This is also the reason I LOVE my CNC conversion. I was not looking for CNC, and initially looked at removing all the crap from the mill. Once I saw what a mill can do with CNC I will never go back to manual.

Boring head in a boring bar tool holder for a quick change toolpost, if that works on your machine very easy and inexpensive to make. It'll make short work of that aluminum part.

or to plot the locations every couple of degrees

Click to expand...

Requiring only a smaller radius tool and some "figuring"

cinematechnic said:

...

My previous setup worked well but was greatly overcomplicated and took forever to set up (see photo below). It was a custom radius cutter holder held in a Sherline 8700 CNC rotary table, sitting on a Sherline linear slide, bolted to the side T-slot of my Schaublin 102N.

Click to expand...

I do by far like this setup over other hard swing attachments. I'll bet first try was a major challenge.
All swing types are a bit of a pain to get set right if a thou matters.
I may be wrong as most of my world is swinging the opposite rad on cutting tools.
BTW when doing such the rad on the cutting tool has to be very good and true to form. Kiss hand ground goodbye.
Bob