How do I harden the ends of 1/4 silver steel that I am using for a clutch pushrod?

email (option): Gasboy@btinternet.com

Hi Peter

Redden it with a gas torch & quench it in water

Be sure the clutch rod is correct length & clutch is operating correctly before you harden it

Best regards

Job

email (option): Jonnyob1@googlemail.com

I wouldn't use the rod just hardend as it would be to brittle, after hardening you will need to temper it, heat away from the end and watch the colour moving to the end, when the dark straw or blue reaches the end quench in water this will temper it.

You'll need to temper the ends after hardening to impart some toughness, left untempered the ends will be brittle. So after hardening clean up the ends with some emery cloth or wet and dry sand paper so that the ends are bright again then slowly reheat the ends until the colour changes to a straw colour, then quench. If you go beyond straw colour towards blue you will need to repeat the hardening process.

email (option): spacemonkeym@gmail.com

Oops, posting at the same time.

email (option): spacemonkeym@gmail.com

Or quench into old sump oil.
The less severe quench will still harden the tip but not as deeply as with a water quench.
As soon as it stops boiling take it out and allow to cool slowly there will be enough heat left in the rod to finish the temper.

email (option): wariron@tpg.com.au

I heated mine to red then shoved it in oil,
i just noticed that despite this the clutch lever end has
squashed into a concave ball bearing shape, and its mushroomed out a bit.

What`s the thinking on using a 1/4" stainless steel rod

A few years ago someone (and I wish I could remember who!) found a brazing type rod. I believe it was called stellite, and all you did was heat the end of the push rod and braze this stuff on. A small group of us have used it on a variety of bikes and it works very well. I just wish I knew who sells it!!

email (option): Peevee1965@yahoo.com.au

Ian answered this last year (March 12 2012. can't figure out how to paste the link at this time of the morning so here is the gist of his post:

The pushrod you are buying should be made from 'silver steel' and have the ends hardened. Silver Steel is a flame hardening high carbon steel and it is easy to make alterations to a pushrod made of this material if required.
First you will need to soften one end.
Heat the end to red and allow it to cool naturally in the air. This will soften or 'normalise' it.
Once cold shorten the rod to the desired length..but take care. Small reductions in length make a lot of difference. When you are happy the rod is correct and the clutch adjustment is correct with the rod fitted, remove it and heat the end you have altered to red, quenching it immediately in cold water.
This will re harden the end.
Then clean the end off with some emery cloth until you have a bright finish.
You will now have to 'temper' the end. (this softens it slightly and makes it less brittle.)
Place the end into a fairly gentle flame and allow it to slowly heat up. You will see the steel gradually change colour as it heats, first to a very pale yellow, then a darker yellow...then brown. This is an indicator of the changing temperature of the steel.
Allow it to go pale yellow and just as it starts to darken quench it very quickly in cold water. The rod is then ready to use.
If you go too far and the rod goes brown simply heat it to red, quench it again, clean it off and have another go. Lubricate the rod well with some light oil before refitting...Your stainless rod was not a suitable choice...the material is far too soft

Cheers
Pete

Some stainless is ok for this type of job, it will simply work harden. Don't forget that Vincent used to use Stainless pushrods in their engines as standard, so depending on the grade it may be ok to use stainless, but I'm presuming that it would be one of the harder grades ie more nickel content

email (option): davmax@ntlworld.com

That is true but commonly available grades like 304 and 316 may not be suitable. So first you would have to determine which grade would be suitable for the application..then find a source for it and, if you buy a standard stock length, you will get 13 feet of it..or half that if the stock supplier will do that. Then there is the question of cost...
Or, you could buy a standard length of 1/4" silver steel which is 13" long and will make any of the BSA pushrods for about £2.00..available from most Engineering factors such as Buck and Hickman, RS Components etc..As silver steel works perfectly well there's not much point making life more complicated than neccessary...Ian

email (option): ian@wright52.plus.com

Undoubtedly preaching to the converted here but I found this nice explanation about silver steel properties in my notes which may help somebody. It’s written from the point of view of making home workshop tools.
Cheers
Pete

Silver steel is a commercial low-carbon tool steel produced as accurately ground lengths of round and square bar. Common lengths are 13" and 18" (though any reasonable length can be had from the factory), and diameters up to about 1". It is sold in the semi-soft or 'annealed' state. The steel comprises 1.1/1.2% carbon, together with the addition of about 0.35% manganese, 0.45% chromium and 0.1-0.25% silicon. It is particularly useful in the home workshop because it can be easily machined prior to hardening, the latter process being quite simple to carry out with nothing more than a small propane torch and a bucket of water.
After machining the work is then heated to 'cherry' red (somewhat above the transition temperature of 800 degrees) to form the iron carbide before quenching in cold clean water. Brine is actually a little better as the bubbles formed are finer. Cherry red is a term often used but in fact is quite difficult estimate, being dependent as it is upon the levels of ambient light. Perhaps a better method is to use the disappearance of magnetic attraction as a measure of the critical temperature. Quenching should be done by dipping the hot metal bar vertically into the water then swirling it around a little, this technique will minimise any tendency to warp which might occur should one side cool (and therefore shrink) appreciably faster than the other.
Upon removal from the quench it will be noted that the surface is black and probably scaled. An old-time tip to avoid this is to coat the metal with soft soap prior to heating, upon quenching the metal will retain a nice even silvery-grey surface. In any case, the metal now needs to be polished back to base metal to facilitate the tempering process. One characteristic of polished steel is that upon heating through a range 150 to just above 300 degrees C it progressively changes colour from faint yellow through straw, brown, blue and finally near black. We can use this colour change to indicate the temperature of the metal and so control the drawing of the temper. Each stage of the colour change indicates a percentage of the carbide compound remaining in the steel, and therefore it's hardness. The objective of tempering is to reduce the hardness to the point required and then stop the carbide breaking down any further by immediately quenching in cold water. Useful indicators are:
• Pale yellow - hardness 750-800 Vickers - Still quite brittle but very hard.
• Pale straw - hardness 720-770 Vickers - Suitable for machining mild steels. Low resistance to fracture.
• Dark straw - hardness 700-750 Vickers - Suitable for home made taps, scribers and the like.
• Purple-blue - hardness 650-700 Vickers - Suitable for chisels and punches.
• Dark blue - hardness 640-690 Vickers - suitable for springs

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I would say just transitioning from pale to dark straw is the correct colour for a pushrod..If tempered back to brown they are too soft and the ends will not last..A water quench is also the correct method...If you are in the U.S and reading this, silver steel is known as 'drill rod' in your part of the world...Ian

email (option): ian@wright52.plus.com

Most places will cut stainless rod to the length you require,a good quick fix until you buy/make an original type one[if ever needed]

The problem is if you get the material spec. wrong and the clutch end of the rod mushrooms out it will be neccessary to take off the primary chaincase etc. to remove the pushrod..You can get 5 lengths of silver steel on e bay for £11.50 and no doubt there are cheaper sources, so why take a 'short cut' that may not work?.....Ian

email (option): ian@wright52.plus.com