My Whacheon lathe ball/radius turner

Well, I said I'd do it so here are some pics of my radius turner for my Webb WL-435. I post this with some trepidation. This is NOT an elegant tool. It's not gonna impress this crowd. It's very simple and lacks.... I dunno.... subtlety. I called it caveman-simple on another thread, and that's about right.

Moving on from my inferiority complex, the thing is nice and beefy. Top plate is around 1" thick and bottom around 1-1/4". The toolholder in the middle channel there is fitted nicely to a sliding fit- a few thou clearance. Holes are all 1/2-13. The top plate has a polished 1-1/8" SS shaft (SS, because I had a nice piece of T304 around) pressed into it, which is fitted very closely (too closely?) to a bronze bushing in the bottom plate. Zero "bad" play that I can feel; the bushing is a bit tight, but only a bit, and it's a new assembly, so I'm approaching changes cautiously.

What is really neat about this tool on this machine is that there's enough room to mount it and still have full functionality of the carriage/crosslide/compound. Meaning I don't have to remove the compound to use it; it can stay mounted.

It mounts to an angled slot.... like 1/2 a dovetail... on either side of the carriage. I fitted that all together very carefully. As you tighten the end plates (with the three bolts per side) it pulls in and down. Seems to work great. You can see it in one of the pics.

I need to add a handle for more difficult cuts that need some leverage. Waiting to inspiration to strike there. Also, I'm using two grub screws to retain the 3/4" indexable cutter holder. That's a little dicey given that the cutting forces are trying to pry that holder out of the slot. I may add a top plate.

Being able to leave this mounted means it'll get used a lot. I'm actually pretty pleased with my tool- crude as it is.

That's 2" aluminum stock for scale.

Pics:







I'm gonna pull it apart to try different lube in the shaft/bushing; I'll take a couple more pics then of the seperate pieces.

Looks like nice things are coming out of Fiddlefart these days. I might have to swing in and check it out.

D'oh. Forgot I had these. Here's a few of it in pieces.





With the top plate upside down to show the shaft:

bridgedog said:

Looks like nice things are coming out of Fiddlefart these days. I might have to swing in and check it out.

Click to expand...

I would love that. And that goes for all y'all.

I faced the scale off the plates on the lathe- hence the concentric circle tool marks. That's not from the top & bottom plates rubbing together. They can't; the bushing is mounted a little proud in the bottom plate, so there's a decent little bearing shoulder there.

Tom,
Looks like a nice stout tool. Mass is good! Yes, you sure will want a nice long handle of say 15" or so. My Holdridge 3D is that long. The longer it is, the better contol you'll have. I would personally not keep her mounted to the machine. As you say, the plate is proud of the base. Fines will surely get under there and scratch the surface. All in all, you did great!

Nice! It's simple, fits your lathe, looks good, is hell for stout (in the local parlance) and works well. A winner!

A suggestion for the handle and fastenings, if I may. I'm assuming that the entire unit can be rotated 180deg for generating large internal radii, so the handle would need to work in that position, too. The handle could be fastened to either side of the rotating "base" and a dogleg/offset in the handle could clear the compound as you pull it towards you. If the shank of the handle was square where it's fastened to the side of the base, and drilled both directions, the handle could be rotated 90 or 180 degrees, which would allow it to be used for turning both on the front and back side. And a comfortable grip at the other end, maybe knurled?

Another suggestion. (While I'm pontificating ) A wear plate between rotating parts could support the toolbit under heavy loads. Prob not necessary for light cuts, but for when you get brave and hog some material.

Neil

Nice work, my wife says she wants one of what your making on it !

That's funny as hell- my wife made a similar comment but that's all I'm saying about THAT!

Steely Dan... haha.

I'm trying to decide if I want an aluminum ball enough to waste the material to finish it off. So far I'm thinking not. I hate wasting non-ferrous material$.

I've made 40 or so beer tap handles for my brewery friends and they'll be needing more. Those have a radiused part on them that I've been doing on the Logan. That'll be the first actual "work" for this tool I suspect. In fact it probably won't get used a whole lot. It was an itch I needed to scratch mostly.

I did prototype some very large parts out of PVC for a company that thought they were going to get the parts molded in production, but then found that the guy who'd ballparked the mold costs to them was out of his freaking gourd and his numbers changed exponentially once it was time to actually do it. Anyway, we've been batting around the idea of me making them- machining them. The drawings have big radiuses everywhere to eliminate stress-risers I guess, and when I made them the prototypes, I just banged out a quick form tool. It was tough to avoid (cosmetic) chatter marks. Anyway that'd be another job this beast might get soon.

Not elegant?

I disagree. Quite strongly.

I like it! A large washer made from brass shim stock could address Neil's suggestion for a wear plate and also provide additional support. And to address Ray's caution re: fine chips getting in the works, how 'bout turning a recess and installing a felt wiper?

-Jeff

Interesting. A wiper of some type- felt, or the soft plastic like you see on way wipers- is not a bad idea.

An elegant way to do the handle eludes me so far (not sure I'm completely understanding your idea, Neil) and is the most glaring "d'oh!" with the tool.

Last night I adjusted the bushing-to-shaft fit by a skootch <grin> and it swings freely now. I might have forgotten to mention it in this thread, but the bushing, pressed into the bottom plate, was left about .075" "proud" in order to keep the plates seperated as well as essentially function like a washer in that the shoulder of the exposed bushing is also bearing.

Looks nice ! If you rotate your compound round 90deg from where it is in the photo, could you connect a link from the compound to the radi cutter ? Ie winding in and out will pull the rad cutter round ?

You should be able to get a reasonable sized arc doing this, obviously complete 'bell-end' cutting would not be possible

Long Tom said:

An elegant way to do the handle eludes me so far. . .

Click to expand...

Spot-face a flat on the radiused surface that's on the tailstock end of the swiveling plate and drill+tap for a rod/handle that you can simply screw in when you need to use it and remove when you don't. Functional, and if you turn a fancy round knob to put on the end of the handle it might even be elegant.

-Jeff

That puppy looks great. I know it would slightly add to the complexity of it, but rather than riding on the top of your bushing, it might be kind of sexy to sneak a thrust bearing in there. Although it might give you more problems with crap getting in your bearing but it's just a thought.

great design. I like the use of insert tooling I already have.

Here's a NeilCAD sketch of the handle I had in mind... (No laughing or snide comments about my drawing skills allowed.)



If there were holes drilled and tapped in both sides of your top plate, the handle could be fastened to either side. For instance, if the dogleg were up and you were turning an external radius on the front side, the handle could clear the lathe compound as you pull it towards you. Probably bolting the handle to the back side of the top plate would be most convenient for "front side" external turning, but being able to bolt to either side just allows more options.

If you were to turn an internal radius (on the front side) by starting cutting action at the center of the part, the handle could be fastened (90 deg from the previous example) so that the dogleg is towards you. You wouldn't have to reach so far across the lathe while exiting the cut.

Another option is to turn an external radius on the back side of center with the lathe running backwards. The handle could then be mounted with the dogleg towards you. And if the top plate and toolholder were reversed about the pivot to generate really large internal radii, tapped holes at both ends of the top plate would allow for fastening the handle at the tailstock end. It's a versatile tool you've made, with lots of different configurations possible- I was just thinking that the handle mounting should be equally versatile to be comfortable and safe.

Hope this explains a bit better. (I am often accused of being cryptic....)

BTW, your turner is elegant!

Neil

Give your self more credit, gorgeous work. Any chance you'd be disappointed if I copied it?

Tim

Nice job Tom, looks nice and solid.

I've been trying to understand what Neil is saying about the handle, and I think I get it. When you reverse the whole thing for concave turning, The handle will be on the other side. So what about just tap a hole straight through at right angles and then you can just screw the handle in from the other side when you reverse it.

Of course you'll need to turn a ball for the end of the handle..

Ray

Having ridden motorcycle for 40 + yrs., I always hated when some guy presented his rebuild others had to say things like "you should a done this" or "why didn't you do it like this". But here I go. Maybe a bronze "wear" plate between the upper and lower pieces in a semi-circular shape might help in easing movement. Like a crescent moon or horseshoe shape. I like the felt chip shield idea.
And maybe a friction device if it gets too "floppy".
My Clausing has a cross slide with dovetails like your but the DRO is in the way. I have wanted to change that to use the d-tails but never done more than eyeball the solution. Might have to now.