Screwfix bolts
bigandy - 7/3/05 at 02:40 PM
Afternoon all!
I'm just about to order a collection of bolts and nuts and washers etc for various suspensions parts on my car. I am aware that some of the
parts I require need to be grade 8.8, and some are grade 10.9. I was wondering if anyone knew what grade the "high tensile" bright zinc
plated bolts are from screwfix. It doesn't say on their website...
For example, look at this:
http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=06069&id=19305
I need that bolt to be a 8.8grade.
Also, I'm presuming that it is okay to replace a grade 8.8 bolt with one that is a higher spec bolt (for example grade 10.9 or 12.9?) could
anyone comment on the validity of that assumption of mine?
Cheers folks!
Andy
ned - 7/3/05 at 02:43 PM
I've ordered some cap head bolts from screwfix and they were bzp 8.8 iirc
hope this helps..
Ned.
David Jenkins - 7/3/05 at 03:14 PM
I believe that zinc plating needs to be heat-treated in some way to prevent cracks propagating into the base material - passivating? Because of this
I've used Screwfix bolts only in non-critical areas where I'm usually "over-bolted" anyway.
For my suspension I used aircraft quality bolts that are cadmium-plated - probably overkill, but they are an exact fit, have the right amount of
unthreaded shank, and are more than strong enough.
rgds,
David
bigandy - 7/3/05 at 03:19 PM
David, do you have a link to a supplier of such bolts? I'm not sure about these screwfix bolts for critical areas, but for secondary fixings,
you can't beat them for the price!
Cheers
Andy
Mix - 7/3/05 at 04:09 PM
The BZP bolts I've received from Screwfix are annotated 8.8 but as David implied, they are standard bolts that in some applications may require
cutting down to achieve the correct amount of plain shank.
Mick
Ian Pearson - 7/3/05 at 08:00 PM
quote:
David, do you have a link to a supplier of such bolts?
These guys might be able to help.
LAS AEROSPACE
clbarclay - 7/3/05 at 08:04 PM
quote:
Originally posted by David Jenkins
I believe that zinc plating needs to be heat-treated in some way to prevent cracks propagating into the base material - passivating? Because of this
I've used Screwfix bolts only in non-critical areas where I'm usually "over-bolted" anyway.
Not necesserily crucial but I've pulled apart both old merc and landrover backends, the merc bolts are all plated and practically glide out. As
for the landrover, you must be kidding, like the rubber bushes theres no substitute for a gas axe.
[Edited on 7/3/05 by clbarclay]
David Jenkins - 7/3/05 at 08:43 PM
I got mine from these people quite a while ago...
Aircraft Spruce
Trouble is, I couldn't find their UK agents on Google - I got mine over 5 years ago. Not particularly cheap then, but I believe that
they're bl**dy expensive now. You're also likely to get stung for import duty, as a full set of bolts is quite heavy and HMC&E
won't ignore the package.
The good thing is that they're EXACTLY the right length, which I couldn't manage elsewhere - solid shank through the bracket and bush, to
the point where I couldn't do it up tight unless there was a washer under the head and nut.
Minimum tensile strength of 125,000 PSI, with shear strength to match - the bracket would be long gone before these bolts broke! 
David
quote:
Originally posted by bigandy
David, do you have a link to a supplier of such bolts? I'm not sure about these screwfix bolts for critical areas, but for secondary fixings,
you can't beat them for the price!
Cheers
Andy
clbarclay - 7/3/05 at 08:56 PM
quote:
Originally posted by David JenkinsMinimum tensile strength of 125,000 PSI, with shear strength to match - the bracket would be long gone
before these bolts broke!
125000 psi for those bolts. A grade 8.8 bolt is 120350 and 10.9 is 150800. So those bolts you used are not much stronger than normal 8.8 bolts.
David Jenkins - 7/3/05 at 09:01 PM
I was more concerned about the shank length...
DJ
NS Dev - 8/3/05 at 08:23 AM
quote:
Originally posted by bigandy
Afternoon all!
I'm just about to order a collection of bolts and nuts and washers etc for various suspensions parts on my car. I am aware that some of the
parts I require need to be grade 8.8, and some are grade 10.9. I was wondering if anyone knew what grade the "high tensile" bright zinc
plated bolts are from screwfix. It doesn't say on their website...
For example, look at this:
http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=06069&id=19305
I need that bolt to be a 8.8grade.
Also, I'm presuming that it is okay to replace a grade 8.8 bolt with one that is a higher spec bolt (for example grade 10.9 or 12.9?) could
anyone comment on the validity of that assumption of mine?
Cheers folks!
Andy
To directly answer your questions, i wouldn't use screwfix bolts in safety critical (as in steering/suspension/harness mounts) areas, but fine
elsewhere.
Yes, it is fine to substitiute a "better" grade of bolt i.e. 10.9 or 12.9 instead of 8.8, it will just definitley definitely not break
rather than just definitely not break!
David Jenkins - 8/3/05 at 08:35 AM
Yep - what he said!
Most of my nuts and bolts are Screwfix or similar. The only reason I bought fancy airplane bolts for the suspension was that I was too lazy to hike
around town looking for a decent supplier of industrial-grade bolts.
There's plenty of fastener suppliers who can sell you the right length bolt, if you're prepared to spend some time looking for them.
David