I've got 3 items that connect to a stainless rod each of the 3 items have an 8mm hole and I've got some rod which is a tad over 8mm. Now I could increase the holes in the bit that will slide over and buy some stainless mig wire and weld them up but I've had a thought that I could heat up the little bits and slide them alone the rod and when they cool should be nice and tight.

Now my question is will heating them up discolour them?

If so, is it possible to clean them back up, they do have intricate detailing on them which could be tricky to clean and they do have a nice polished machined effect on them which could cause cleaning to be a problem.

Any ideas fellas & gals?

Cheers

Rich

"Pickling paste" is what's used to clean up the dark marks left after welding SS

how much is a tad bigger than 8mm? interferance fit is close tollerances, with smallest bit in the freezer and other in the oven may work but will depend on what sizes you are talking about and also how far you need to slide them on, and that size of material will not hold a temperature for long and as soon as they touch will start to equalise, also you can weld stainless with normal mild steel mig wire but will potentially rust. think it depends on what you using/doing?

How much is a tad over 8mm. Remember fits are inredibly close tolerances.

General rules for fits (or what I work to anyway):

Assume shaft fitting in a hole then:

Shaft 0.01 to 0.02mm smaller will be a nice sliding fit. Or a fit suitable for retaining adhesive

Size for size will be a light press fit - i.e gentle taps with a mallet. I normally use this for bearings in pulleys or bungs for holes which I dont want to stick in with retaining adhesive

Size to 0.02mm bigger will be a heavy press fit and will require some serious whacking to get it together, especially in harder materials.

Shrink fits depend on the size of the parts but generally arent much more than size to 0.01mm tight.

Stainless will discoulour when heated, but it will polish out.

David

[Edited on 16/1/10 by flak monkey]

They do vary from size to size up to 0.01mm but no larger, the majority are size for size. So would tap down but would scratch the rod I think. The furthest one need to go down the rod about 200mm.

Think I'll just have to have a play with some of the ones I've knackered making the jig today.

Thanks for the comments so far.

Rich

depending on the application you could make them a slide fit then loctite them use retainer used to be 649
no discolouration
pickling paste will remove most heat generated discolouring but in my experience it leaves a dull finish
what are you making?
Ray