Ball ended Hex (How to machine?)

[mgraham1930]

I have a part that a customer who wants me to make a part and it has a Ball ended Hex on the end. It is the same as a ball ended hex that you would see on some Hex Keys with a .500" dimension across the flats at the widest part.
I have attached a sketch of it.
I know it could be machined on a 5 Axis Machine which I do not have. Does anyone know how this would be produced easily and quickly?
Any suggestions would be much appreciated.

 

[Garwood]

An indexer on a mill? Is this a trick question?

 

[daringwilliams]

what about a, live tooled lathe

 

[David Utidjian]

How many does your customer want? If only a few just buy some ball ended hex keys of the appropriate size and quality and weld or silver braze or whatever into a bore or pocket on the rest of the part.
To make it yourself; One way would be to use a surface grinder or tool and cutter grinder with the "ball" radius profile dressed in to the wheel. Mount the part on a holder that can be mounted into one of those 5C hex collet blocks, or a spindexer, or an indexer. Then grind one side of the profile, rotate 60 degrees, grind, rotate... until it is done. Depending on the arrangement of your T&C grinder you may be able to use a plain thin grinding wheel and "generate" the profile on the ball end directly.

 

[CarbideBob]

One can do this on a B-port or lees with a $50 indexer, a vise and some angle blocks. Go cheap and no need to buy the angle block set.
Go way cheap and a Harbor Freight mill/drill will suffice.

"The answer is easy if you take it logically."
The op does not state equipment available or part volume. Hints here would be nice.

 

[eKretz]

High quantities would probably be polygonal turned. Plenty of other ways if you just need to get a lower quantity done. For instance, this one was done on a bench grinder. Quickie for chainsaw bar adjustment.

 

[EPAIII]

It could probably be done with a Unimat and two indexing attachments. The head stock spindle would be mounted on the vertical accessory post (used for drill press and milling work). But the spindle would be mounted horizontally, roughly parallel to it's orientation when used as a lathe. A thin abrasive wheel would be mounted. This abrasive wheel should have a diameter large enough so that the slight arc it produces between the corners of the hex is negligible.

One indexing attachment would be mounted on the cross slide with it's axis pointing up. It is under the abrasive wheel and it's axis would be roughly aligned with the (front/back - your choice) edge of the abrasive disk. This indexing attachment would be manually rotated for the circular arc movement to obtain the ball curve.

A horizontal bracket would be mounted on the first indexing attachment. It would extend sideways for the needed distance and would hold the second indexing attachment at it's outer end. The second indexing attachment would be mounted with it's axis horizontally and pointing toward the center line of the first indexing attachment. This second indexing attachment would provide the 60 degree indexing for the hex shape. The part would be held in a chuck or face plate mounted on the second indexing attachment with the end to have the ball/hex on it's axis and with the center of the ball shape aligned with the vertical axis of the first indexing attachment.

The part should have a rough ball that is larger than the hex/ball to be achieved, turned on it's end. This would minimize the amount of material that the thin abrasive wheel needs to remove. The indexing would be done with the abrasive wheel just touching the axis of the part. The first indexing attachment would be rotated manually by the right angle bracket. A couple of adjustable stops can be rigged to stop this rotation at the axis point and at the extent of the ball where it joins the body of the part. These do not need to be very strong, just enough to let you know when to stop the manual rotation in each direction.

The horizontal bracket needs to be long enough to allow the full length of the part to be mounted on the chuck or face plate used on the second indexing attachment. The choice of chuck or face plate would depend on the shape of the part.

The other brands of small machine indexing attachments would work just as well. But I am not sure if those machines would allow the spindle to be mounted horizontally at a suficient height for this set-up. If the overall part is too large for Unimat sized indexing attachments, then two larger ones or one indexing attachment and one rotary table could be combined in this manner on the table of a vertical milling machine. An accessory, high speed spindle could be attached to the vertical axis of the mill to hold the abrasive wheel. This would allow the vertical feed of the mill to be used to eliminate the dish shape between the corners of the ball/hex.

 

[memphisjed]

I am not seeing how to do it with 5 axis? 4 (x,y, rotary, z is optional) seems obvious.

 

[implmex]

Hi All:
Here's a home made carbide form cutter to make ball ends for dental subperiosteal implants in cobalt chrome on a pantograph without using an indexer:
You could just walk around the profile with the balls standing up.
The cutter was made with a surface grinder to gash the flutes and the pantograph with a diamond bur to make the profiles.
This was in the days before you could easily just order something on the internet... it's vintage early 1990's when you were really someone if you even had a VMC or a computer.


And here's a hex ball, wire EDM cut with a rotary axis.
Obviously the ones to look at are the first and fourth parts of the bunch:


Lots of ways to do this...these are two of the more exotic ones.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[MrWhoopee]

Agree with David Utidjian. If this is single or small quantitiy, buy ball end wrenches, cut the end off, turn down, insert and silver solder (preferably from the opposite end). Added advantage of already being hardened as long as you don't overheat.

 

[Bill D]

Does it need to be hard? Simple one off method hex collet block in the milling machine to form the hex. Then turn the groove in the lathe.
Bill D

 

[Kingbob]

you could mill them with a lollipop cutter

 

[cyanidekid]

this is one of those hilarious threads where everyone has an idea. some interesting (nice work as usual Marcus!), some won't work (Bill, the grove is hex also), some just whacky.
id say send it out if its any quantity, but the surface grinder is an effective way if you have one. could be done with a grinding wheel in a vertical mill spindle too, but the grit will get everywhere

 

[L Vanice]

https://www.amazon.com/Bondhus-43916-ProHold-Socket-ProGuard/dp/B00RBGK2XQ

Price $17.36 here and it is ready to silver braze to the disc with 18 holes and engraved numbers.



Larry

 

[memphisjed]

this is one of those hilarious threads where everyone has an idea. some interesting (nice work as usual Marcus!), some won't work (Bill, the grove is hex also), some just whacky.
id say send it out if its any quantity, but the surface grinder is an effective way if you have one. could be done with a grinding wheel in a vertical mill spindle too, but the grit will get everywhere

why grind it? A bust (head/shoulder statue) like silhouette in a vertical mill, spin part 45 degrees in rotary/indexer, repeat, repeat, done.

 

[cyanidekid]

why grind it? A bust (head/shoulder statue) like silhouette in a vertical mill, spin part 45 degrees in rotary/indexer, repeat, repeat, done.

well at 45 deg indexed twice you would get the first two facets of an octagon wouldn't you?
its easier to create the form by dressing a wheel than creating a custom cutter, but for one for shop use just grind it like eKratz did, (I've done a few the same way) but that might not be professional in appearance to do on a customer part.

 

[eKretz]

well at 45 deg indexed twice you would get the first two facets of an octagon wouldn't you?
its easier to create the form by dressing a wheel than creating a custom cutter, but for one for shop use just grind it like eKratz did, (I've done a few the same way) but that might not be professional in appearance to do on a customer part.

No, definitely not...

If I had to do a one-off for a customer as a part of a hand tool or similar I'd do it the way Marcus noted - or Larry's braze-in. If it were part of a turbine I would grind it.

 

[memphisjed]

well at 45 deg indexed twice you would get the first two facets of an octagon wouldn't you?
its easier to create the form by dressing a wheel than creating a custom cutter, but for one for shop use just grind it like eKratz did, (I've done a few the same way) but that might not be professional in appearance to do on a customer part.

do the full profile side cutting, you do two facets per index.

 

[implmex]

Hi memphisjed:
I assume, from your description, that you are laying it down sideways and profiling it on the CNC with a little endmill, small enough to drop into the cove at the root of the ball.
If you don't have a CNC, you could still do it with an indexer (or vise and hex collet block) set up on a rotary table on the Bridgeport, or if you're one of the old school guys who still runs a pantograph, you could use that to describe the cutter path.

It's a good and pretty easy way to make the shape, and as you say, it's only three indexes to get all the way around the part.

You've described a great method if you only have a few to do and if you don't need to make time on them.

If you need to go fast, I've still had best success with a form cutter and the hexball standing up.
You can gang them up and really go to town, no indexing required and one simple pass to make a facet.
If you need them nice too, just run two cutters, one roughing and one finishing...they'll still be pretty quick.

There are lots of grind shops who can knock up form cutters for you...AB Tools in California is a resource I've used in the past and they did excellent work for me.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[Scottl]

Lot's of ideas but one huge problem:
No idea of the OP's machinery or skills. Without those it's like putting a note in a bottle and casting it into the sea.

Certainly what comes to mind is an indexer or collet block and a 2-axis CNC mill. For this even a Spindex would work.

But again, without further information from the OP we are just guessing.