Alignment when silver soldering help

[picclock]

I'm about to start manufacture of a part which requires a 10mm dia steel tube brazed into a 10mm thick steel plate. The rod is hardened steel and needs to be at right angles to the surface of the other part. Problem is that I need to allow about 4 thou clearance to allow the braze to flow (2 thou each side) but I need the steel tube to be at right angles to the steel plate, and 4 thou is quite a lot of potential (highly technical term follows) wobble . The tube is 33mm long, so only 23mm will protrude above the plate.

The best idea I can come up with is to bore a piece of 25mm steel rod 10mm and hollow out the part where the join will occur, sort of like a three legged stool with very short legs and a very thick seat.

I have also considered centre punching the ends of the hole to hold the tube correctly before brazing, but I'm not sure how successful or accurate this would be.

I have come across this issue before and have always resorted to bodging it, on one occasion even reheating the joint to reset the position.

Any tips or advice on how HMEM experts :bow: resolve this problem most welcome.

Many thanks for your time

Best Regards

picclock

 

[abby]

Just a couple of points Picclock ;
the heat required for silver soldering will soften the hardened part , unless you can heat it to hardening temperature and quench which means brazing or copper brazing rather than silver soldering.
You do not need 2 thou clearance for silver solder.
Johnson Mathey state that easyflo no.2 will give total penetration for a 1" dia silver steel rod pressed into a 1" reamed hole in a 1" steel plate.
You might make the tube a press fit into the hole and allow 1 or 2 thou clearance for 1/16" depth of the hole at one end.
Silver solder from the clearance end , even without total penetration this will be a strong joint.

 

[Ken I]

Picklock - Make three equispaced and same size punch marks - like you suggested - both sides of the hole - drive a pin through to "size" it (you can follow this with a reamer to ensure squareness) - knock your tube in and silver solder.

Another bodge would be to straight knurl the tube to achieve much the same thing.

Personally I'd put chamfers both sides and rely on the solder filling this annulus.

Like the previous post - silver solder will destroy the hardness of the hardened part.

Ken

 

[picclock]

Thanks for the replies. I thought I'd get away with the hardening issue as my silver solder melts at 640C, so I may have to rethink the method of fixing.

I could try an interference fit or a heat shrink/ interference fit - at least it would be square. The part is not subject to heat during use so maybe even fixing with engineering epoxy may be an option.

Oh well, I can see some head scratching coming on for this one. ???

Many thanks for your expertise.

Best Regards

picclock