Steel for a tommy bar

[John ReeseParticipant @johnreese12848]

I don't think it will make a lot of difference what steel you use. Brazing heat will anneal the steel. The strength gained from prior cold working or thermal treatment will be lost.

[HopperParticipant @hopper]

Posted by Chris Evans 6 on 15/01/2017 20:26:25:

Lots of suggestions but I am still searching for a grade of steel to use.

4140. That's the SAE designation. Not sure what you call it on that side of the pond.It's readily available and is a chrome moly steel. Tough as.

If you are going to thread the end and screw it in, you could get the two pieces nickel plated separately. Tape up the thread on tommy bar so it will fit in the female thread afterwards.

[Bill PudneyParticipant @billpudney37759]

For what it's worth, I would use Loctite, one of the high strength ones from the 600 series (I think 609 or 638 but I'm not sure, have a look at their website) Way stronger than any soft solder, despite what others may think……. Just use in accordance with the instructions.

cheers

Bill

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bill Pudney on 17/01/2017 09:26:35:

For what it's worth, I would use Loctite, one of the high strength ones …

.

So would I, Bill [see earlier post] … but Chris wants to have these assemblies electroplated.

MichaelG.

[Ian S CParticipant @iansc]

If Chris gets the pin plated separately, leaving the part to be inserted into the hole unplated, then use shaft lock Loctite to assemble the two parts.

Ian S C

[HopperParticipant @hopper]

How was the original made? Probably made a good tight fit and clouted in with a hammer.

[Chris Evans 6Participant @chrisevans6]

Hopper, not sure on original method. The tommy bar is broken off and the rest has 90 odd years of rust. Got to make six complete axles.

[David George 1Participant @davidgeorge1]

I have used before the method of a slight distortion of the shaft in similar cases where you just trap the pin in a vice with a 12 mm hardened dowel at 90 degrees and it distortes the pin just enough to make it a press fit localy which you can't see when installed won't fall out, and dosn't weeken the pin. I use a small V block in the vice to hold the pin. Just try it on a scrap piece and I think that will do.

David

Edited By David George 1 on 17/01/2017 23:04:59

Edited By David George 1 on 17/01/2017 23:06:42

[Author]

Posts