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Today's question - locking a bolt.
David Jenkins - 7/5/09 at 10:43 AM

1. I plan to use an M8 bolt/screw to hold something securely.
2. What it's holding does not rotate, but it will get a lot of vibration and sideways shocks, although only at a low level.
3. The bolt, and what it screws into, are both stainless steel so I will need to grease the threads to ensure that they don't bind.
4. I will need to undo the bolt occasionally, quite possibly in difficult circumstances (e.g. on the side of the road, in pouring rain).

Number 4 means that normal threadlock is out of the question (unless you can get 'soft grip' types).

I don't like (or trust) spring washers.

The ideal solution would be a Nylok bolt (they have a nylon insert in the thread, near the tip) but I've never seen those on sale in the UK.

Any other bright ideas?
(The forum's track record for suggesting options I hadn't thought of - or didn't even know about - has been very good so far... how about this one? )


Steve Hignett - 7/5/09 at 10:45 AM

You CAN get different grades of threadlock, so there's one answer for you, but I've not anything to do with Nylock bolts I'm afraid!

ATB


sickbag - 7/5/09 at 10:47 AM

How about drilling a hole near the end of the bolt then inserting a 'R' clip. They're easy to remove by hand but shouldn't come out in service.


blakep82 - 7/5/09 at 10:47 AM

can you get to both ends of the bolt? what about drilling a hole through the end of the bot and put an R clip through?




ha ha i'd have got in with that one first if i didn't look for a picture

[Edited on 7/5/09 by blakep82]


Howlor - 7/5/09 at 10:51 AM

Or if you can't get to the other end can you still put a hole through the bolt head and an R Clip but into a hole on the chassis to stop it rotating?


Steve


sickbag - 7/5/09 at 10:54 AM

quote:
Originally posted by blakep82
can you get to both ends of the bolt? what about drilling a hole through the end of the bot and put an R clip through?




ha ha i'd have got in with that one first if i didn't look for a picture

[Edited on 7/5/09 by blakep82]


That's the quickest I've been outside of the bedroom!


Howlor - 7/5/09 at 10:55 AM

Norlock fittings I have seen used and seem to work very well.




Steve


chrsgrain - 7/5/09 at 11:00 AM

Drill a hole through the bolt head and wire it to something close by?

Chris


tomgregory2000 - 7/5/09 at 11:00 AM

quote:
Originally posted by Howlor
Norlock fittings I have seen used and seem to work very well.




Steve


These are amazing


nick205 - 7/5/09 at 11:05 AM

David - I'm still intrigued as to what you're up to....?


David Jenkins - 7/5/09 at 11:08 AM

Cor! Quick answers!

The bolt will only have its head showing - no room to put an R-clip anywhere. It would also be vulnerable to pillocks who like to undo things...

I don't want to be playing with wired bolts in difficult circumstances!

Those Norlock things look interesting, but would they tend to carve up the metal they're fastening over time? (stainless don't really have a very tough surface).


David Jenkins - 7/5/09 at 11:09 AM

quote:
Originally posted by nick205
David - I'm still intrigued as to what you're up to....?




I'm keeping quiet 'cos some people will probably hate it... not that I care if it fixes what I hope it will fix...

Also, if it doesn't work as well as I'd like, I can abandon it without comment.

There - that's mystified you even more!

[Edited on 7/5/09 by David Jenkins]


tegwin - 7/5/09 at 11:15 AM

Wouldnt the simplest solution be to wind a nylock onto the bolt....

Then screw the bolt into your "part".... then simply tighten the nylock down onto the "part" to lock the bolt inplace..

Its done everywhere else... so dont see why it wont work on yours!


MakeEverything - 7/5/09 at 11:16 AM

Weld a nut one end, and use a lock tab washer?


David Jenkins - 7/5/09 at 11:22 AM

quote:
Originally posted by tegwin
Wouldnt the simplest solution be to wind a nylock onto the bolt....

Then screw the bolt into your "part".... then simply tighten the nylock down onto the "part" to lock the bolt inplace..

Its done everywhere else... so dont see why it wont work on yours!


A bit of info I forgot to include in the original posting:

I don't want any bits sticking out to catch pedestrians, etc. Not that I've got to pass SVA/IVA, but it does seem the decent thing to do!

The head of the bolt (either hex or socket cap-head) will be recessed.


MakeEverything - 7/5/09 at 11:29 AM

quote:

I don't want any bits sticking out to catch pedestrians, etc. Not that I've got to pass SVA/IVA, but it does seem the decent thing to do!



Depends where you drive!!!


907 - 7/5/09 at 11:34 AM

Hi David

PTFE tape on the thread.

It will also save using an anti seize paste.


Trust me. I'm a welder.

Paul G


David Jenkins - 7/5/09 at 11:35 AM

And it depends on what sort of sticking out bits you're talking about!


David Jenkins - 7/5/09 at 11:36 AM

Paul - cheers - I'll give that a try...


craig1410 - 7/5/09 at 12:06 PM

Must say, I'd just use a spring washer - is there a reason why you don't trust them?

There are a number of types of spring washer - I tend to use the single split type in most cases, especially for high torque applications but I use the "frilly" type for lower torque applications. Never had any problems with them coming loose.

Cheers,
Craig.


iank - 7/5/09 at 01:00 PM

I've seen caliper bolts with the nylon coating, maybe there's an OEM bolt that would work.

Here's a really wacky one used on Mini's (metric bolt shank with unf thread )
http://www.minispares.com/Product.aspx?ty=pb&pid=35377&title=CALIPER%20BOLT%20FOR%20TURBO%20CA...

Personally I'd go looking for loctite 222 or 243
http://www.eriks.co.uk/threadlock/eriks.asp?title=Threadlock-Adhesive&pageid=861


oldtimer - 7/5/09 at 02:11 PM

Nut and lock nut?


efiniste - 7/5/09 at 02:16 PM

Another vote for Nord-Lock here. Never had a problem with them coming loose or chewing up bolts. Fantastic product.

Steve


blakep82 - 7/5/09 at 02:19 PM

drop of nail varnish on the bolt
acts like nyloc nuts, but you can put a tiny tiny drop on
or even a drop of superglue if you can't find the colour of nail varnish you're after


UncleFista - 7/5/09 at 04:59 PM

Not possible to use a stud with a nyloc on it instead of a bolt ?


rusty nuts - 7/5/09 at 06:14 PM

Caliper mounting bolts are normally 8mm with a coating of locking compound . Should be fine for your purpose David.


dave r - 7/5/09 at 08:12 PM

loctite 242 or 242a
the last one is the softest, and good for things like carb screws
dave


MikeRJ - 8/5/09 at 07:56 AM

quote:
Originally posted by craig1410
Must say, I'd just use a spring washer - is there a reason why you don't trust them?



Nasty things, break into two pieces as often as not and chew up the fastener and part you are bolting down.