is there any reason not to buy this one? seems like a very good price to me- but don't really know what the bolts are on my bike, do they tend to be metric?

you need to tap a thread for your bike?

yep, the pinch bolts for the rear axle and also the pivot pins (on an orange, where the dust caps go to cover the bearings).

im pretty sure the pinch bolts are m6 but don't know about the pivot ones.

anyone know if the aforementioned set is any good?

i would be amazed if they werent metric…

measure them with a vernier caliper and see..just to be sure yourself though.

i dont even know what one of those is, never mind own one. will a ruler work 😆

ok! yes if you can be pretty precise..just measure to the extremities of the threads and you'll see what the thread is.

seems like it will be an m4 then. back to my original question, will that set be ok? it seems awfully cheap compared to some others…

on another little diversion- if the threads are stripped and wont clean up properly, will it be possible to tap it using one size bigger then use bigger bolts?

I wouldnt buy it, cheap tools mean you do the job twice..

So, the threads are stripped? Im assuming otherwise you wouldnt be looking at those tools..it depends where this is and if there is enough material left once you go bigger.

I wouldnt advise without seeing it tbh…call Orange?

Wouldn't touch them matey, cheap rubbish by the look of it, most likely to snap off in the hole and create all kinds of trouble.
A decent set from draper their pro range is ok would be a much safer bet.
Obviously a bit more expensive but a lot less trouble.

Alternatively your good LBS should have a set for a one off job.

To get a proper tap set you need to spend more (a lot more).
The best these will do is clean out a damaged thread – which is sometimes all you need.
But even then you could do more harm than good.
Screwfix might be worth a look, the quality will be the same but at least you can see what you're buying (assuming you have a local branch).

Most bike threads are metric, but there are some odd ones like pedal thread, BB thread.
Mech hanger thread is also odd, I think M10 fine (most threads are Metric coarse).

what about this set then?

Decent taps are made from HSS (High speed steel) whereas cheaper ones are made from carbon steel.

To be honest i wouldn't bother buying a set as most of the taps you won't need, just go to a decent tool stockist like Cromwell Tools and buy the ones you need (M4, M5, M6). You need to ask for 2nd lead hand taps and a t-handle to suit.

Looks better but a proper set will have three taps/size (starting, second and plug).

Which you don't necessarily need for cleaning out a thread, especially in aluminium, but a poor quality tap may do more harm than good.

To be sure of getting the right quality you would have to go with a 'name', dormer or similar and you will pay much more for their quality.

TBH I would not make a £1000 frame a starting point to teach myself how to tap a thread, though most mistakes are recoverable at a price…