Steel for a tommy bar

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

Hi Chris

If your worried about it bending can't you make a socket to fit over the spindle end and the tommy bar, bit like a starting handle but will drive both ways? En24T or a spring steel should be tough enough. I can't comment from experience but if it was my problem that is what I would be looking to do.

Cheers Michael

EN 16T is ideal for what you are doing and is easily available.

EN16T, EN16 steel stockholders and suppliers, delivering to the whole of the UK. This grades is commonly supplied as EN16T to the BS970 specification. It is a low alloy high tensile steel supplied with a tensile range of 850 to 1000 N/mm² depending on ruling section. EN16T has a good resistance to shock with excellent ductility. It offers relief from temper brittleness. Subject to ruling section larger sizes in EN16 can be supplied in other condition such as EN16R and EN16S. EN16 as rolled (un heat treated) is also available, usually in larger diameters. EN16 is an alternative alloy steel grade to other chromium and nickel chromium high tensile steel specifications, offering excellent ductility, freedom from temper brittleness and is readily machinable in the supply condition.

David

Edited By David George 1 on 15/01/2017 21:08:27

Thank you David, EN16T it is then. This is my usual go to grade for motorcycle spindles so the 1/4" diameter tommy bar will be of the same grade. I wanted reassurance of using something that did not bend easily at the small diameter. Chris.

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.

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.

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

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

MichaelG.

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

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

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.

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