here is one of the many stakes I make, most are on a 20mm ( 3/4" ) shank to fit my range of stake holders, I can also fit a 'stop collar' on them for use in a hardy hole and different shank sizes to order.

this is a new 88mm high carbon ball bearing ( about 3 1/2" ) I make ball stakes from ball bearings up to 100mm ( about 4" ) and mild steel schrooms up to 200mm ( about 8" ) diameter.

I also make a wide range of other stakes for armouring and other metalwork

 

I have been pondering making a ball stake for the hardy myself.  Other than the initial ball cost, everything is quite easy and it would generally be no more than an easy afternoon's project (depending on whether you go as far as installing a slot for a wedge).

The question that kind of leaves me in the dark is "how high?".  I can guess but since I've never had one to use, I can't anticipate how high the ball should be set to cover the oddball project that comes up *next* year (decade).  Anyone have suggestions from experience on just how tall is convenient without becoming a bit annoyingly tall?  For the sake of argument, figure a 1" hardy hole and and unhardened stem.  Is there a benefit of taller that one "discovers" down the road?

It's nice to be able to curve the sheet metal around the ball as you work it so a but of space above the anvil is nice.  You want to be able to work on it in a comfortable position too.  You may want to look at some armour making benches over at armourarchive.org.

well as you can see the tape measure in my pic that is how high I make them unless something else is specified, welding them can be fun, preheat anything over 2" diameter or it will probably crack ( some will still crack but the new ones I buy I know how to treat each size now ).

I do a holder that goes in a stump and a double holder for a VERY  sturdy bench and one for a vice, generally for a hardy hole I put the stop collar on about 3" up from the bottom and for a 1" hardy I add a sleeve of square tube to the shank

here are a few more random items, 2 stake holders and 2 stakes

OP; pitty you're in the UK, as I'd buy one from you 

I'm needing a new raising stake for a set of helm projects 

 

Guess I'll have to make my own