I am in the process of building a little sterling engine for my old mans Christmas present... Machining the parts is causing me grief, but I will get there eventually..


One issue I have.... The crank of the engine is 8mm silver steel rod. I need to attach a 2mm thick steel plate at one end to take the end of the conrod.

These parts are might small so i cant really MIG them....

In a basic workshop with no access to oxyascethylene (SP?) how can I join them together to give a strong result?


I did try soft solder, but that was a silly idea......

Parts are a bit like this:



[Edited on 2/12/11 by tegwin]

brazing is the best thing, if not silver solder them,...

hthBrazing

Silver Solder would probably do it.

Al


Originally posted by tegwin
I am in the process of building a little sterling engine for my old mans Christmas present... Machining the parts is causing me grief, but I will get there eventually..


One issue I have.... The crank of the engine is 8mm silver steel rod. I need to attach a 2mm thick steel plate at one end to take the end of the conrod.

These parts are might small so i cant really MIG them....

In a basic workshop with no access to oxyascethylene (SP?) how can I join them together to give a strong result?


I did try soft solder, but that was a silly idea......

Parts are a bit like this:



[Edited on 2/12/11 by tegwin]

Was thinking silver solder/braze.. but what sort of heat source am I going to need?

Silver soldering (or hard soldering) likes to be up around 450*C. You could do it with one of those butane pen torchy things if the parts are small enough to get hot.

Can you get a good interference fit, and use a dab of loctite?

quote:

---

Originally posted by r1_pete
Can you get a good interference fit, and use a dab of loctite?

---

Loctite 610 (I think) will fix something like that - and you'll only get it apart with a blow-torch!

I used it to fix the wheels on my 5" gauge steam loco...

An alternative would be to make a thread on the end of the rods, a matching thread in the flat bit, THEN use threadlock to hold it together.

Ha! Snap!

In fact, you don't want too good a fit for Loctite - it needs a thou or so to work. Make it too tight and you just push the Loctite out of the joint.

[Edited on 2/12/11 by David Jenkins]

Drill the hole slightly undersize, then put a slight taper on the shaft then warm up that end with a blow torch.
Knock the shaft in with a hammer leaving a mm or so stuck out then turn over and tap the tapered end to a mushroom like riveting a steam boiler to lock it in.
will never shift then.

Russ

I would make the hole an interference fit, press the shaft in and peen the plate to squeeze the rod in place.

I would silver solder it, you will manage with a diy type blow lamp with butane propane mix gas.The other way I would do it if not able to solder it would be to turn the end of the shaft down to 6mm cut a thread on it and tap the plate then assemble with loctite , a plain shaft and hole would probably work but I prefer to use a thread just to be certain that it never comes apart.

What exactly do you mean by silver solder? I have standard plumbers solder... I can also get hold of fluxxed brazing rods. But I can nto find silver solder in any of the usual places.. (machine mart, tool station, screwfix)

http://www.thewelderswarehouse.com/Welding/Flux_Coated_55__Silver_Solder.html

Most welding suppliers should have it.

Cromwell also do it, but more expensive than the welders warehouse.
http://www.cromwell.co.uk/quicksearch?search=silver+solder&x=0&y=0

Braze or silver solder, that's what I do on my live steam stuff.

SILVER SOLDER RODS X 5 SILVERFLO 55 | eBay

Trouble with silver solder is you need the special flux, which adds to the cost.

I'd consider brazing, especially if you can get the fluxed rods.

Popped to the local welding place and machine mart this morning.

Picked up a nice small focused gas torch, some flux and a silver solder rod (£8!!!!) Gave it a go, hard to keep it looking tidy, but seems plenty strong enough :-)

Need to mail order some more silver solder rods from somewhere cheaper, but for the time being... I am getting there :-)

Thanks all

quote:

---

Originally posted by tegwin
Popped to the local welding place and machine mart this morning.

Picked up a nice small focused gas torch, some flux and a silver solder rod (£8!!!!) Gave it a go, hard to keep it looking tidy, but seems plenty strong enough :-)

Need to mail order some more silver solder rods from somewhere cheaper, but for the time being... I am getting there :-)

Thanks all

---