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about cross head screews
02GF74 - 21/8/06 at 07:04 AM

seem to rember reading that cross head screw fail SVA and people fill the head with silcone or similar.

is thatright? (I have them holding the curreont for gear leaver and hand brake)

and the same for button heads? I have many of them, 4 mm, on my bonnet, filling will be a pain to sya the least.

button heads donl;t feel as sharp as cross head -is that takine into consideration?

also does the hight for the head from the surface make a difference to wheterh they are subject to testing or not?

David Jenkins - 21/8/06 at 07:13 AM

I use button-head screws to hold down the top of my tunnel. Mine are hex head, but they're the same as cross-head for edges.

My tester didn't look at them twice - I think he ran his hand over them, once.

David

Humbug - 21/8/06 at 07:15 AM

quote:
Originally posted by David Jenkins
I use button-head screws to hold down the top of my tunnel. Mine are hex head, but they're the same as cross-head for edges.

My tester didn't look at them twice - I think he ran his hand over them, once.

David


David

I have been looking for hex button head screws (as opposed to bolts)- where did you get them from?

smart51 - 21/8/06 at 07:16 AM

There is an SVA rule that "features" less than some mm wide don't have to be radiused, just blunted. Think of radiator grilles, you don't have to use 5mm wire for this.

David Jenkins - 21/8/06 at 07:16 AM

From Clerkenwell Screws in London (Clerkenwell Road) - they're a half-hour walk from the office.

Not a lot of use to you maybe, but they may do mail-order.

David

David Jenkins - 21/8/06 at 07:17 AM

quote:
Originally posted by smart51
There is an SVA rule that "features" less than some mm wide don't have to be radiused, just blunted. Think of radiator grilles, you don't have to use 5mm wire for this.


For this sort of thing, I believe that height is the significant factor - 5mm rings a bell, but I wouldn't swear to it.

02GF74 - 21/8/06 at 07:35 AM

quote:


For this sort of thing, I believe that height is the significant factor - 5mm rings a bell, but I wouldn't swear to it.


yep - that is why I'm asking

thnk it is less then 5 mm though; ok will rtfm.

02GF74 - 21/8/06 at 07:38 AM

quote:
Originally posted by Humbug

I have been looking for hex button head screws (as opposed to bolts)- where did you get them from?


what diameter/length/material and quantity? (BZP, black or stainless)

my local fastener supplier does a huge range.

& let me know how much you're willing to pay - screws &B postage will be at cost and I'll get them next time I pop into the place so if you can wait a couple of weeks, then can do.

Humbug - 21/8/06 at 07:55 AM

quote:
Originally posted by 02GF74
quote:
Originally posted by Humbug

I have been looking for hex button head screws (as opposed to bolts)- where did you get them from?


what diameter/length/material and quantity? (BZP, black or stainless)

my local fastener supplier does a huge range.

& let me know how much you're willing to pay - screws &B postage will be at cost and I'll get them next time I pop into the place so if you can wait a couple of weeks, then can do.


ooh, thanks. It will be a while before I can go and measure/count.

Just to clarify, what I am after is button (dome) head screws with a hex hole on top to take an Allen key. Preferably self-tappers. Are they available?

I'll let you know. Ta

RazMan - 21/8/06 at 08:18 AM

I get most of mine on eBay - just do a search for 'stainless button head' and you will find loads.

02GF74 - 21/8/06 at 08:27 AM

quote:
Originally posted by Humbug

Just to clarify, what I am after is button (dome) head screws with a hex hole on top to take an Allen key. Preferably self-tappers. Are they available?



deffo button head socket screw, like this:


never seen self-tappers - but a quick search show they are available: http://www.engservfast.co.uk/product_details.asp?cref=secscr


self tappers are usually like the ones here: http://www.aaronsself-tappingscrews.com/Self-tappingScrewsTypeAandAB.htm

[Edited on 21/8/06 by 02GF74]

ReMan - 21/8/06 at 08:41 AM

I used Flanged Button heads where visible and contactable, my tester loved them
Like these....
http://cgi.ebay.co.uk/M5-x-12-STAINLESS-FLANGE-BUTTON-HEAD-ALLEN-BOLTS-10-PK_W0QQitemZ8069854401QQihZ019QQcategoryZ25644QQssPageNameZWD1VQQrdZ1QQcmdZV iewItem

David Jenkins - 21/8/06 at 08:50 AM

I'd be wary of using hex button screws as self-tappers - it's all too easy to round off the hex hole (or the key), especially where the pilot hole was a bit too small, or the material a bit too thick or hard (I used to know someone who was too thick, and hard!)

David

Dusty - 21/8/06 at 09:37 AM

If they stick out greater than 1.5mm and less than 5mm they just need to be blunted. 5mm or more and it's 2.5mm radius.
(Theoreticaly if less than 1.5mm they can be sharp as razors)

scudderfish - 21/8/06 at 11:37 AM

http://www.modelfixings.co.uk are good for smaller ones.