Machining a ball on the end of a rod---?

I don't if its worth the effort for just one or two pieces, but here's plans for making a ball turning tool for use on a lathe:

Neat!! I think I'll make one! We did make a radiused cutter by hand to get the press running. Thanks.

Quick and dirty - Machine a slight recess in the end of the rod and silver-solder an appropriately sized bearing ball on it. Regards. Ken.

It won't take the pull.

Without a radius cutting attachment, CNC, or a tracer, it's not easy. If you can get your cutting tool behind the pivot point of your compound, you can swing the radius by pivoting the compound. That's usually not an option, though, and it's very difficult to locate the tool in the proper position to yield a radius. If you have a set of radius gages, use the

5/16" radius as a guide (gage), and rough the radius using a RH cutting tool. Get it close, and finish with a file, then polish. By working carefully, you can generate a very good ball. It's all up to your skills, though.

Harold

Along the same lines but stronger, how about a tolling ball inserted into the end of the rod and physically fixed in some way?

Sorry for the PDF link but I couldn't get anything but a search link which I didn't think would work. This one may not work either.

Might not be as fun as doing it yourself but would be ROUND, strong, and not that expensive.

Koz

Ken Davey wrote:

For a quick-and-dirty, offset the bit to make the tip 5/16" off the mounting center of the compound. Feed with the carriage and swing the (barely)loose compound by hand.

Kevin Gallimore

This certainly doesn't answer your question, but does this press have a clutch and brake system? Maybe a Clarke control on top? The reason I was asking is that it may be easier for your operator's to just use palm buttons or finger buttons positioned away from the die, ram or punch before it will cycle. This type of system requires both hands to make a circuit for the press to cycle. You are probably familiar with this, but I thought I would add this anyway. Pull-outs are a real pain to be harnessed into in a production environment, can't even scratch your ass without unhooking. :)

Jim Kovar Vulcan, Mi

Don't. Purchase a few soft steel balls from McMaster Carr, drill a blind hole in them (hold in collet) and turn down the end of your steel rod for a press fit into the hole.

Jim

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You can buy 'em with the hole already there - solid steel ball knobs - e.g., #6045K56, 1" dia, 3/8-16 thread.

Ned Simmons

It should -- typical strength of a good silver-soldered joint is in excess of 60K psi. But if not, Tig weld the ball on.

In one of the bedside readers, Lautard describes a method of step cutting to rough out spheres. If you think of the circular path your tool must take, as a series of right triangles with identical hypotenuses (is that the right plural?) and simple math gives you the z-x coordinates.

1 in sphere has a 1/2" radius-hypotenuse You use a cut off tool Starting at the end of the workpiece, move the tool .050 toward the headstock. .50-.050=.45 this is now one leg of your right triangle with a .50" hypotenuse Solve for the other leg sqrt(.25 - .2025) = radius of the step = .2179 subtract from the stock radius .5 - .2179 = depth of cut = .2821 Continue the process for rest of the of the hemisphere. move the tool over the width of the cutoff tool and start working on the backside.

Afterward, you coat it with layout blue and file down the steps until the blue disappears.

It works a lot faster if you do the math beforehand

Paul K. Dickman

There is another trick which can be used, if you have the right tools.

Start with a dividing head which can be tilted up to an angle to the mill's table. Set it around 45 degrees for a first pass.

Then put a boring head in the mill's spindle, with a cutter pointed to cut inside its swing, instead of the usual outside.

Bring it slowly down onto the end of the workpiece, and crank the dividing head as you go.

When the boring head's cutter is drawing a circle around the center of the workpiece, you will be forming a ball on the end, with slight cleanup needed on the end, as it will leave a stub the same diameter as the stem connecting the ball to the rest of the workpiece.

Obviously, this is useless information if you don't have a mill, a dividing head with a 3-jaw chuck, and a boring head for the mill -- but then a radius tool is not much use with your lathe if you don't have one of those, either.

Good Luck, DoN.

I'm familiar with the process, but it's quite tedious and slow. In general, you can form a ball using a radius gage as a guide in far less time unless you have already done the math for the stepped ball, and don't lose sight of where you are in the process of generating each cut. I've found it's much easier to just use my tracer!

Harold

I was talking to a fellow with a nice Corliss steam engine model at NAMES yesterday. I asked him if he used a radius turning tool on all the ball ends on the thing. He said no, those were way too slow to set up. He said he uses form tools, made by taking 3/16" thick tool steel of an appropriate size, setting it up at an angle for relief, then hitting it with an end mill of the appropriate radius. He then said he hardens it, not even worrying about temper.

The caveat was he only uses 12L14 for his steel model parts.

Pete Keillor

Ya, if you don't do the math first, you are guaranteed to screw up. luckily Marv Klotz has a programette on his website that works it out for you.

Armed with that it can go pretty quick

I wouldn't want to turn a 6" ball , but a 5/8" would probably be finished before I figured out where the @*$? I left my radius gauge.

Paul K. Dickman

Cheap shot time.

If one wanted to obtain a complete set of radius tools for a lathe, one might consider what corner-rounding end mills look like. Inexpensive import ones do come in complete sets.

Form is correct, relief is already ground in. Already hard.

Mount on center in the toolpost, the machine has to be run backwards for the lefthand side of a ball.

Jim

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