Any question answered...

He/she just wants you to go and do the impression to someone :)

My bad

No, that's the point, I don't want to specify the actual type of element used, because that's up to others to design, while considering user experience, accessibility, etc.

'a form element [or set of elements] from which user can select exactly one item'could be implemented as a drop-down select, a row of radio buttons, or some other kind of widget.

I only want to specify the basic, functional behaviour which is a means by which the user can specify n items from a set x. (Not a list, because that implies the items are ordered, and if and how they may be ordered is another thing for other people to cover)

I think I'll call them 'select single item' and 'select multiple items' and define those terms somewhere.

Yes I didn't mention 'no items', but that's important too, so will include.

The 30mm M6 allen heads I happen to have in my spares drawer, are threaded all the way along. The 40mm M6 Allen heads I have, have a threadless bit below the socket.

1 Attachment

The bolt / screw thing used to be (back in the 70s when I was an apprentice) heads that were hex (spanner) or slot (screwdriver) respectively, with machine screws often being threaded full length and bolts having a plain shank, but this was never a hard and fast distinction.
Google image search for 'm6 30mm socket cap' gives more full length threads than not - I guess it depends on your supplier as much as anything?

Is a 30mm m6 likely to have a shoulder?

The part you're talking about is not a shoulder, it's the shank. If you don't specify full threads when ordering, you might get a short length of unthreaded shank on M6×30 because the thread length is typically around 24 thread pitches for screws/bolts* without full length threads.

*see argument above, and previously. The defining difference is not whether it has full threads, but whether it screws into a nut or into the workpiece. A short bolt will always have full length threads if it is shorter than the minimum thread length for it's pitch, a long screw might not since the assumption would be that anybody using a screw that long is passing through a deep clearance hole before getting to the female thread in the underlying piece, not that they are wasting a lot of time engaging threads for more than two or three times the diameter.

"Full length thread" is always just an approximation, since you can't cut threads all the way to the underside of a bolt head, there will always be either a thread relief or a runout of about one thread pitch.

Looking for some dummy measurements for a 90 mtb and an a good (i.e. cheap to Stockholm Sweden) courier that isn't pick-up to get an idea of price. Anyone know of one?

i went on a ride out a couple of days ago and lost the compression/pressure bolt on the left side of my sugino 75 DDs. I have done some research in finding a replacement bolt, but there are non in stock in the UK, some stores in EU and Japan have them but it is more expensive. They are called M15 bolts. I found this bolt on evans cycles https://www.evanscycles.com/fsa-left-hand-crank-bolt-drive-mega-exo-00119758?1=-1,esvcrea:315905194508,esvplace:,esvd:c,esvtg:aud-644432013583:pla-308122467963,esvo:00119758-NA-NA,esvaid:50080&1=-1&lsft=esvt:55230-GOUKE2390394,esvq:,esvadt:999999-0-1222790-1&esvwa=NISO_Chainsets%20%26%20Cranks_FSA_No%20Year_Normal&esvwa=NISO_Chainsets%20%26%20Cranks_FSA_No%20Year_Normal&esvwc=UK_Shopping_GEN_Components_Chainsets%20%26%20Cranks&esvwc=UK_Shopping_GEN_Components_Chainsets%20%26%20Cranks&esvt=55230-GOUKE2390394&esvq=&esvadt=999999-0-1222790-1&esvcrea=315905194508&esvplace=&esvd=c&esvtg=aud-644432013583:pla-308122467963&esvo=00119758-NA-NA&esvwm=CPC&esvws=Google&esvwt=&esvaid=50080&gclid=CjwKCAjw36DpBRAYEiwAmVVDMJz3Erpi0SioN6fc4dcEmtK0YarEY3rRlgwynQoVEEnjDg5GV1uyOhoC4eQQAvD_BwE

would this work? ....

So ordered some MTB wheels from CRC. Yodel says delivered Tuesday but they haven't been. Seems odd as usual Yodel man has always delivered (well chucked stuff over fence/left in wheelie bin etc!) so doubt he'd have made a mistake.
TL:DR
Wheels bought and tracking says delivered but Ive not received. Paid via PayPal, courier not a Yodel signed service (although 'tracked'). Will I get money back if it comes to it?

Yes

Ideal - thank you

I emailed dolan and they had one in stock but it wasn’t on the website. Got it 11££££

if you can, try to find an All City Def Wish

or Dropout

On-One Pompino (canti) or Pompetaine (disc brakes).

Strap-on under-the-downtube bottle cage mounts, on a carbon bike. Will I die?? What's good and won't damage the frame? Have been looking at the SKS Anywhere and Topeak Versamounts as options (non-metal clamps), recommendations/ experiences appreciated.

You will die, but not sure if this’ll be what kills you

Carbon is designed for a purpose. And possibly may not have the strength to take a strap or the strain of the additional weight.

This is why people might p clip a rack onto a gas pipe steel frame, but most (sane/intelligent) would not do this to a crabon biek.

Your decision.

Are there any 22.2 clamp bars that are flat or anything that isn't a riser/BMX bar?

Might be able to get flat motocross bars

Search ‘7/8 handlebar’ or just ‘motocross handlebar’ on eBay. Loads of different types should come up

Cheers

Same or next day T shirt printing in London?

Mrs chain slipping (and skipping a touch) in the top (largest) 2-3 sprockets of 10sp cassette. Cassette and chain replaced together (prob less than 1k dry miles) and chain length fine. Cheap (sunrace) cassette but shouldn't wear after lightish use and perfectly sound shifting etc in other 7 sprockets. What chance the b screw needs winding (inwards??) a touch? Any other ideas? Loathe to 'try' new chain cassette if all logic suggests it shouldn't be worn

If I want to boost my wifi to the back of the house.

Is this the right thing, or do you need to plug an ethernet in and/or buy something else?

Cheers.

https://www.amazon.co.uk/TL-WPA4220-Powerline-Extender-Broadband-Configuration/dp/B00DEYDF8I/ref=sr_1_4?keywords=wifi%2Brange%2Bextender&psr=PDAY&qid=1563183126&s=prime-day-secondary&smid=A3P5ROKL5A1OLE&sr=1-4&th=1

I am looking to replace a pair of Surly Tyres 650B x 41
I ordered from Wiggle 650A x 40C which seemed to be the nearest they had listed.
Clearly a wrong decision since they don't fit.

So since no 650B x 41 tyres are listed. What tyres would fit?

have a look at the 650b thread for tyre reviews and recommendations.
650b is also 27.5