Twisting en24t

After breaking my high tensile 130 plus mph flash steam propeller after the August crash I'm in the process of making another one.

I used a nickel air/oil hardening steel for that one but have very little left.

I'm thinking of making it out of en24t as I have enough of that material.

When I tried using that before when I cold twisted it about 30 degree it cracked.

The section twisted is about 2" x 1.25" x 0.156" thick it is initially a Ø1.25" bar that has the 2" sections milled in it .

After twisting it is hand finished using angle gauges and a simple jig profiling it into a propeller.

I would like to leave the en24t in its present strength as to anneal will loose that property if I do anneal to try to stop it cracking how do I with basic heating equipment get it back to that strength it or is it too specialised.

Others have used en24t for props but if they twisted it as well I do not know.

Edited By Windy on 21/08/2015 08:15:13

Lovely looking bit of work, Paul.

You do realise that if/when it becomes airborne it will fall foul of the CAA rules on metal props

Neil

Only a loose thought but I have arc welded(cheapo Lidl welder) small thin parts recently and you have to be in-and-out in a second or two to prevent the piece from being damaged by heat

This does however red heat the entire body of the workpiece quickly and efficiently, making it possible to plunge the workpiece in, say oil, or twist it while still hot as a blacksmith would

Forging( battering it with a hammer while hot ) can also increase its strength

You would have to experiment of course to acquire these micro skills, if you were to try this route, and the small spot weld would need to be removed

Edited By Ady1 on 21/08/2015 10:42:30

If it continues to fly I will put wings on it as have not seen a flash steam model plane for many years.

I wish I could do work as good as that!

This website might help.

http://www.westyorkssteel.com/alloy-steel/engineering-steel/en24t/

If you can borrow a copy of 'hardening tempering and heat treatment' by Tubal Cain, that might help as well

http://www.amazon.co.uk/Hardening-Tempering-Treatment-Workshop-Practice/dp/0852428375

If you do have a go yourself, I'd do a test piece at the same time and try to do some destructive testing on it. I wouldn't want to be stood in line if a blade parted company. Best of luck

Hi Duncan **LINK** is my favourite metal supplier when I went the other year for en24t for my steamer cylinder head was told they are specialising in tool steels now.

Fortunetly he found a big diameter lump at a very reasonable price could possibly make a full size head from it as well.

On the web from them you can get the specification sheets for the various steels they have been very helpful.

Any way thanks all advice welcome.

PS

The book forum members advised me to buy volume 2 on motorcycle construction by John Bradley is like rocking horse manure to find I did get Volume 1 and has helped to get me up to speed on more modern racing motorcycles.