A work colleague of mine is building a 1/6th scale tank and to date as spent a fortune on it.

Having dinner tonight he asked me to guess how much he as been quoted for the following........

M2.5x10 hexhead sets with 3.5A/F (normally 5mm for this size)

M2.5 full plain nuts again 3.5A/F as opposed to 5mm.

He needs 150 each, anyone any ideas where from ? When he told me how much he had been quoted for the above I nearly fell off the chair, just short of £800 including the vat, anyone help, ideas where from ?

The quote was from micro fasteners in the UK so there out.

the 0.5mm wall thickness make them very special nuts. Could he not just get normal nuts and file them down? He could thread them all on some rod and have them ground.

I have a guy at work who is a keen model engineer (he used to make model steam trains etc for a living), who may be able to source the bits(or even make them specially for less than that). I'll ask him today if he's in (I'm not sure what shift he's on today). Are they normal steel?
Regards
Hugh

stupid question but M2 would have smaller heads surely - can;t they be used?

no doubt he'll have a lathe so nuts = hex bar, drill, tap and part off.

set screws no to easy but maybe using the nuts made earlier and soldering onto 2.5 mm stud?

yes, it will be time consuming.....

if the nuts are not iso then they need to be made to special order = £££££

Ok, Graham isn't interested, but he gets his special nuts and bolts from "ITEMS" mail order, 01427 884319. They make 'reduced head' BA bolts/nuts for model engineers. Note that 7 BA is 2.499mm dia, 0.48mm pitch , 4.37 AF on nut. I'm not sure if the reduced head ones are one or two BA sizes smaller - 8BA = 3.85 mmAF, 9BA=3.32 mm AF. Cost per hundred less than £10! Graham says they deliver next day in most cases.

Also 3.5 mm is not a standard hex size, which is probably adding to the cost of your specials as the hex bar will have to be specially made.

Most model engineering suppliers sell BA size bolts with a smaller size head as it is more to scale for steam locos etc so maybe worth looking at BA size as most metric sizes have a near identical BA equivalent.
Paul

These people are worth a try. Sample batch of special screws made for work, I believe around £150 for 100 off

http://www.pts-uk.com/