Locking nut to stud - superglue or studlock?

[gidon]

Hi
What's the best way of locking a nut to some studding - it's a M8 stud and nut. I can't lock it with another nut. Or is there something better? I don't have any welding equipment (still).
Thanks
Gidon

 

[jasonB]

Studlock would be the best if its a tight fitting thread but if its a bit slack then superglue, in either case clean both surfaces well.

Other options would be locking two nuts together, nylock nut, drilling through the nut & stud and inserting a pin, silver soldering would work on that size with a decent blowtorch/lamp

Jason

 

[Anonymous]

As jasonB said Studlock is probably your best bet. Another , quick and dirty, method I've used is to center punch the junction of the nut and studding two or three times, holds quite firmly.

HTH

Steve

 

[gidon]

Great thanks Jason. I like the pin method too. I know I've asked this before - but looking up an old thread - I'm still not sure what torch I would need for silver soldering? Would this give me everything to get started:
http://www.toolstation.com/search.html?searchstr=67849
http://www.toolstation.com/search.html?searchstr=71066
http://www.toolstation.com/search.html?searchstr=43379
Thanks Steve - another idea to try ...
Thank you
Gidon

 

[jasonB]

Those blowlamps would take quite a while to get the metal upto temp, this causes a buildup of carbon on the work which is not something you want, they are OK for thinner/smaller items.

I use a Bullfinch blowtorch on a 4.5 propane cylinder, Machine Mart do somehing similar This will give all the heat you need and the bottle will last ages

The problem with coated rods is that there is nothing to keep the metal clean while you are heating it. Better to get a proper powdered flux that is mixed with water into a paste together with a length of silversolder. A stick of 1.5mm wire and a 50g tub of flux will go a long way, try here

The flux acts as an indicator of when the correct temp is reached, first the water will boil away and leave a white "foam" as you carry on heating this foam will turn into a liquid, at this point you should feed in the solder which will flow round the joint. On small items it is sometimes easier to place a small length of solder on the joint and then heat until it runs. All metal must be spotless - clean with emery/scotchbrite and then with thinners. SS does not work well at filling large gaps but does need a few thou to flow into.



Jason

 

[johnnyb]

try to get a castellated nut and driill just the stud would allow tightening and adjustment. welder to do this would be very cheap though imho.

 

[OllyK]

I'm guessing you never want to get this off again??

Polyurathane glue works well on metals and expands to fill. I used it to hold a chunk of 4x4 to an rsj.

 

[gidon]

Thanks Jason - just the ticket. I'm going to give this a try ...
Thanks Johnny although not sure I understand .
Olly - yes permanent join - PU another option hadn't though of - thanks.
Cheers
Gidon

 

[johnjin]

Hi Gidon

Jason has got it exactly right but if this is just a one off buy a tube of metal weld glue or Plastic Padding. Super glue is only good to stop the nut vibrating loose and I would guess Studlock is for the same.

Best wishes

John

 

[jasonB]

Stud lock is one of the high strength grade thread retainers and used for "Permanent" thread locking as opposed to screwlock (low) and Nutlock(medium) . It will take a lot of effort to move the nut.

A retainer would be even stronger but the tollerence of fit needs to be quite tight for it to work, I doubt a length of studding and nut with maybe 75% thread engagement would be a close enough fit.

Jason

 

[Bean]

Stud lock is one of the high strength grade thread retainers and used for "Permanent" thread locking as opposed to screwlock (low) and Nutlock(medium)

That does depend upon the grade you buy, some are also oil resistant and will tolerate a lot of oil on the surfaces to be joined. You should also note that standard thread locking compounds are not heat tolerant, and not permanant on an M8 thread anyway.
For a permanant joint you need to use a mechanical method of locking. eg peening, welding, pinning, taper pin or half and half drilling.

 

[TheTiddles]

If the nut is at the end of the thread rod, locate the nut then bang a centre punch into the end of the rod, like holding the head on a hammer it expands the rod outwards and keeps the nut on, it's the way it was done before thread locking agents, apparenly, I'm not old enough to know that for sure...

Aidan

 

[dickm]

If you go down the silver solder route, then see if you can find some oddments of fire-brick to make a miniature hearth. This will speed up the heating process no end compared to heating in free air.
Forgot my bits of old fireplace when we moved, and I've cursed about it several times since.

 

[CHJ]

gidon, I use a MAPP canister torch I got from Axminster but I can't find it on their site now, similar to the ones you reference.

Very fast for something like your 8mm bolt job 1min at most.

Even something as big as this is possible with a little patience if you use the lower melting point silver solder (cadmium content)


Be prepared for a shock on rod and flux prices, although a little rod goes a long way if you just wet the joint with it, it is as strong as it gets, filets etc. add little to the joint.

The reflective fire bricks or at a pinch themalite building blocks are a great help.

 

[gidon]

Thanks chaps for the very helpful suggestions. I want to try silver soldering - I fancy getting more into metalworking anyway. Might just pop down B&Q or Halfords and see what I can get down there ... I'm not feeling very flush at the moment so don't want to spend much.
Cheers
Gidon

 

[Racers]

Hi,

I got some flux coated rods form B&Q but they are really thick I strugled to melt even with a MAPP torch them so I cracked the flux off and used some thin strips of brass instead.

Pete

 

[gidon]

Thanks Pete for the warning ...
Cheers
Gidon

 

[gidon]

This link has some great info on brazing / silver soldering:
http://www.laymar-crafts.co.uk/tech6.htm
Includes this link to a whole online book on brazing which is very informative:
http://www.handyharmancanada.com/TheBra ... /bbook.htm
Looked into getting a propane gas cylinder + torch but it'll come in too pricey. Think I'll try with a MAPP torch that B&Q sell for around £40.
Thanks for the advice.
Cheers
Gidon

 

[jasonB]

Just watch out for the USA/UK use of the word braze. In the US they tend to use it to describe silver soldering(silver brazing) but in the UK if you are talking about Brazing then it is usually refering to a higher melting point alloy, something like Sifbronze which needs 850 deg C as opposed to say Easyflow No2 silver solder that only requires around 610 Deg C.

To use the higher temp alloys you really need oxy-acetylene which is not an option in the home workshop or it can be done with carbon-arc equipment which is what I have used. The advantage with Brazing is that a fillet can be built up, my uncle was a bicycle frame builder, to see all the frame tubes flowing into oneanother is a joy to behold, my custom made mountain bike is joined in this way.

Jason

 

[CHJ]

Gidon, check your PM's

Edit: e-mailed files Gidon but as you are BT they may take a while if BT doesn't like my attachments, they are at the web address in any case