I've had a couple of pikes break on ECW pikemen in transit - does anyone have any good tips for replacing them?

Ringo did a video where he replaces Ashigaru pikes with sewing pins: https://www.youtube.com/watch?v=7c74z_0Ow_c

What I am doing: cutting of whats left of the pike immediatly above the hand; then drilling a hole into the hand, 5 or 8mm - this is the tricky part...

For replacment I use brass wire, its easy to cut to the appropriate length and you can, if you like, create a new tip by sanding it down.

I have takn to using fishing line for my flag poles...They bend so are much more surviabale in play and transit. They work for spears but would not work for Pike though. But the repalcement of just clipping off the existing ones, drilling a hole (or making a grove) and glueing them shoudl work for spears as well.

I hadn't realised there are differnet sizes of pins, well duh my wife (Quilter) said.

I currently drill with an 0.6mm drill and place a 0.5 mm pin in the model. Buy HSS ground bits rather than the cheaper HSS rolled, they penetrate the metal better and blunt slower. Got through quite a few bits as a blunt (ish) bit is not your friend.

I try to drill in or behind the hand. I have repalced all my Kontos (15 units of 18 men) over three armies Samatian, Dacian suppport and Late Imperial Rome.

It is worth the effort, allthough the the Late Imperial Romans didn't lend themselves to it so well. In some instances I couldn't get a good vertical drill so I drilled at 45 degrees which worked well.

This is what I've done

This is why, they were dropped and the Kontos bent.

Looks really good. I have 'dropping pike problem on my 15mm pikes and so yes thats one of thing which really helps in 6mm.

which tools do you use for this kind of micro-drilling?

A pin vice is the best option.  If you are in the UK Maplins is a good place to get one.  They are a hand operated micro drill.  Some are operated by a helical rod that the drill rotates around to get the drill to turn some are completely hand operated.  It sounds difficult but it isnt that tricky.