Any question answered...

Toestraps?

The answer to so many 'what's best for strapping this thing to that thing' questions, bike or non-bike related

Totally agree!!

Shit in what way? Don't last long, slow to cut or fragile?

How thick are the ones you're using? Are you using the leading edge or the bottom of the disc to cut?

Do they look like this?

Or this?

Hilti

Invariably the right answer... as long as someone else is paying.

Actually in this case it’s not, for cutting discs there not the best or actually the most expensive.

What kind of grinder cordless/corded,what size and what kind of power is it?

I think they are good in a cost vs quality way. I don’t do enough to warrant super posh ones, but don’t want another trip to ER with a disc stuck in my wrist. I also alway wear a heavy weight shirt when I’m grinding/cutting now.

I may be a bit biased as Hilti are in some ways a competitor to my employer.
The Hilti disc sells for about £1.10 you can get comparable discs about 10% cheaper, for about £2 you can get a ceramic disc that is faster and lasts longer.
But yes Hilti are a safe bet

"Ahem, h'actually I think you'll find..." [continues ad fucking nauseam]

It’s very rare for me to be able to bring my area of expertise to the general public.

(Normally if people ask me what I do I reply I sell nuts and bolts, nobody yet has said “that sounds interesting tell me more“)

I sell nuts and bolts

that sounds interesting tell me more

10x50mm is our best selling size

Don't last long and fragile! Currently using the first type you've posted there. 1.2mm thick.

@Dibble - cordless but I'm not sure on power actually.

Is it a 115 or 125mm grinder? I’m putting in a samples request later I’ll add some to it.

Re cutting discs for metal, can second what Chaley says. Those, or I’ve had good results with the 1mm Makita ones. The unbranded discs don’t last long enough to make them worthwhile and they do shatter everywhere.

I’d never use a 3mm cutting disc these days. In the 90s, fine, it was all you could get, but not today.

Cut with the leading edge, ie forward, not down: the discs will last longer and be less likely to shatter, but cut more slowly.

This holds for battery, mains or petrol and all sizes.

We use whatever happens to be available and I couldn't tell the difference, except for some brand from (I think) the Czech Rep. which weren't all that.

10x50mm is our best selling size

That's a classic

If it was a classic the closest would be
3/8 x 2 surely?

115 I believe!

It's a bit tricky to get a good angle some times, you just sort of have to cut with whichever part of the blade you can make contact with!

appols for a****n link - but i really like velcro one-wrap - hook on one side, loop on the other.
i bought a big roll and have used it for loads of stuff and keep some wrapped around my bike racks for strapping random stuff on.
https://www.amazon.co.uk/VELCRO%C2%AE-Brand-ONE-WRAP%C2%AE-double-Strapping/dp/B0777LN5VP?th=1

I have an old taclight which takes two CR123 batteries. My question is; is there a single battery that takes the place of the two?

Velcro is a good idea.
I've wedged the lock in the top of the rack with a toestrap holding it for now, thanks for the toe strap suggestion above^
It would be cool to have a lock holster on the side of the rack so I can utilise the top of the rack at some point.

Some people use a 16650 (or 18650, which is a bit fatter) but the voltage is a bit lower which could reduce the light output.

Oopsmark do a specific holster

is there a single battery that takes the place of the two?

Side by side or end to end? In some cases, you can use one CR-P2 (223A) battery or two CR123A cells interchangeably where the mechanical configuration is side by side, the electrical configuration is series connection and the contacts are suitably designed.

Lithium rechargeable 17670 is mechanically the size of two CR123A cells end to end, but at 3.7V rather than the 6V the device was expecting it's a matter of experiment to see whether it's a viable alternative. Some inverter driven circuits will be fine with it as they are expecting to see <2V/cell from a CR123A towards it's end of life.