Help Need On My Design and Possibly Welding

[Bob HeppleParticipant @bobhepple92956]

I have been trying to manufacture an Aid for People with Disabilities something I tend todo alot of in my own limited way. I was asked to produce a special hook that is mounted in stainless tubeing which is not a problem if you look at my Photo in my album it is made of 3 components I inteded to get them Tig Welded but when a frind did the weld they blew them or what did weld altered the properties and now they bend too easily.

They are 2.3stailess rod held in the centre by a special holder I made from 8mmD stailess parted down to 3mm

I sent 12 of these units too the welder and they are useless if I went down the road of welding anyone with ideas of how to do this I have NO welding expertese at all ask me to solder a pcb no problems

Can anyone help

[Bob HeppleParticipant @bobhepple92956]

[michael howarth 1Participant @michaelhowarth1]

Bob……..could you not silver solder the parts together? Much less fierce an operation than welding I would have thought. I have recently silver soldered some stainless steel components together and found it to be much easier than expected and of course the joint is very strong.

Mick

Edited By mick H on 02/11/2012 19:36:14

[I.M. OUTAHEREParticipant @i-m-outahere]

Hi Bob .

Welding 2.3mm dia rod would not be an easy task but not impossible .

The heat from the weld may have relieved the internal stresses formed during the manufacturing of the stainless rod or it has gotten so hot it has burned out some of the elements in the material .

Try silver solder as it is done at a much lower temp than welding .

Maybe the special holder could be modified ?

What if instead of machining the flat across the top and trying to weld the hook to it maybe drill and ream a hole at the required angle then feed the rod  through this hole .

You would have to form one of the bends after it is fed through the holder then you could use an epoxy to retain it .

The other rod i would cut a thread and loctite it into the holder .

 

Ian

Edited By SLOTDRILLER on 02/11/2012 20:47:31

[Ian S CParticipant @iansc]

I presume you are using a suitable grade of stainless, maybe ask your welder friend. Ian S C

[TerrydParticipant @terryd72465]

Hi Bob,

I'm with Ian and Mick on this one. Silver solder is the way to go. with such a fine job. There is a lot of information here which may help you.  There is some interesting information here, especially the advice to post heat the job to prevent cracking.

Best regards

Terry

Edited By Terryd on 03/11/2012 09:11:17

[Bob HeppleParticipant @bobhepple92956]

Thanks All for your input.

I have considered Silver Solder, I know nothing of the process for doing this, so will look at the link you sent me Terryd, I will look over to cup alloys aswell. Yes Ian s c, the stailess is a suitable grad. I was rellying really on someone I thought would do a good job it was he who sugest tig welding, I think it was all heat and no fenesse. I have thought of other ways to make it, the piece in the centre is grooved and the rod sits in it flush thinking this would add to the strength of the unit.

Thanks again for your inputs

Bob

[John Stevenson 1Participant @johnstevenson1]

Bob, if you could leave a bit of the round circular connector on so it doesn't break into the 2.3mm hole then this lot could be held with hi strength Loctite.

In turn this means easy home assembly and no post heat cleaning.

John S.

[TerrydParticipant @terryd72465]

Hi Bob,

Thinking again about the problem, if you could leave the connector a little larger to have a complete hole as John suggests and the loading is not too high then soft solder (see CuP alloys page I sent) would be more than adequate. The connector could then be filed down to the rod if necessary. That way only low heat is needed and there would be no cleaning necessary as with Loctite.

Regards

Terry

[John Stevenson 1Participant @johnstevenson1]

Posted by Terryd on 03/11/2012 14:27:11: there would be no cleaning necessary as with Loctite.

Regards

Terry

.

?????

Don't get that bit Terry? You mean cleaning before Loctiting or after ?

I loctite loads of stuff, get thru about 2 of the small ARC tubs a week, [ buy these as spilt tubs cost less ] and a quick wipe as the bits go together is all I do.

Same applies prior to assembly, quick wipe and bodge on.

[Bob HeppleParticipant @bobhepple92956]

John / Terry d thanks for your inputs I had alook on cup Alloys was thinking about the 2207 lowtemp gear its the torch thats got me worried I could handle the Pencil torch but not sure if it would be hot enough John S whats your thoughts onthis as you know me well I dont want a fire LOL

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

(1) Eliminate the weld altogether and make a mechanical joint – any of :

Make block with through hole for S hook but enter as straight and bend afterwards . Plain hole for other bit . Crimp to lock .

Two coverplates and two screws .

One folded over coverplate . Two screws or crimp to lock .

Two machined half blocks and two screws .

(2) Make a proper joint suitable for either welding or brazing . No joint block just bend end of handle part over for a short distance so as to run parallel to centre part of S hook . Long exposed joint easy to weld or braze and tolerant of imperfections .

If stiffness matters an additional strut could be fitted in similar manner .

(3) Find someone with resistance welding gear .

MikeW

[Author]

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