Cylinder head valves

Curious if anyone has made any tooling out of them ,also cylinder head long bolts . Chap at work is rebuilding an engine and he offered me the valves and the bolts . I thought I could make some small boring bars if the valves are hard enough to use on aluminium and brass . Anyone tried this ?

Sean

Hi Sean I would be wary with the steel in the valves, they are made from various materials, some with welded on heads some with welded seat material and some stems are drilled plugged and filled with sodium to aid cooling. Inlet valves may be different to the exhaust valves.

David

You don't write what type of engine is being rebuilt but if it's petrol or diesel then DG1's opinion should be followed. Decline the offer.
The consequences of you trying to grind sodium-filled valves are horrific.
Check on Google if you've got any doubts and watch this idiot:-
**LINK**

(Edit typos)

Edited By Fowlers Fury on 04/12/2018 23:30:28

Not really worth the mucking about with unknown metalurgy to make a boring bar out of a valve. Easier to make a conventional boring bar to hold a piece of known quality HSS. In fact, they are so cheap to buy these days its no longer even worth making them yourself.

One thing a used valve can be handy for is to make a tool height gauge for your lathe. Simply turn a point on a piece of 1/2" diam. bar, cross drill a hole to fit over the valve stem and drill and tap a hole for a pinch bolt to bear on the valve stem. Stand the valve upright on the lathe cross slide, or bed if you prefer, and set the pointer to match the tailstock centre height then nip up the pinch bolt. Speeds up setting tool height greatly.

Head bolts/studs are usually some kind of high tensile steel, similar to what allen head bolts are made from. But they have been stretched and heated and cooled a million times so they may or may not be useful for making things out out. Usually tough to machine but ok. But with used bolts you never know if they are on the verge of failing (that's why your mechanic mate is discarding them.). They can make handy drifts and punches etc.

For info:

Sodium in small mounts into water - fizzes around until it touches the container edge, then the hydrogen produced burns with the typical yellow flame of sodium. Typical classroom experiment (behind a safety screen, all the same)

Large lumps of sodium will heat and burn the hydrogen formed in an energetic way. As it floats on water, it is more likely to spray only if/when trapped against the container. Not a safe school experiment.

With it jammed in a non-floating capsule, like the valve head, it sank but generated plenty of hydrogen which exploded when the valve head was propelled to the surface. Very dangerous!

Sodium melts at just below boiling point of water. Reaction rates generally double every 5 degrees or so. Liquid sodium reacts much more violently! So one can see how his little ‘experiment’ got out of hand very quickly.

Potassium (next group 1 metal) in small pieces always generates sufficient heat to ignite the hydrogen formed, even when free-floating. Caesium reacts explosively.

Hopper is right about the head bolts - up to a point. One-use head bolts/studs are tightened beyond their elastic limit when tightened down, so cannot be used again. They usually need annealing, to make them easier to machine, for other uses.

Magnesium I've read is the metal that machines best of all. Unfortunately it's risky because the swarf can catch fire, and, once burning spraying it with water causes an explosion. I guess Sodium would be much more likely to catch fire than Magnesium when being cut, and because of the way the metal reacts with water, any bits flying off would cause severe damage to eyes and skin.

That's the theory, but has anyone actually machined into a Sodium filled valve stem? As the metal is soft and weak perhaps the stem collapses before any damage is done, in which case the risk is chemical burns while cleaning up the mess. Except the swarf might be smoking, which would warn you off touching it. I don't think Sodium reacts with Cast Iron or Steel.

The school experiment with Sodium is well known (at least to those who did Chemistry). Not seen any accounts of what happens when machining Sodium. I think the results could be either nasty or relatively harmless. With suitable precautions, any volunteers prepared to find out?

Dave

Sodium is easily cut with a knife and tarnishes as you watch it being cut. Very reactive. With a melting point of less than 100 C, I would not attempt to machine it in free air - within the valve stem was clearly OK - of sorts!

Magnesium is a group ll element and far less reactive than Sodium. Yes, it burns with a strong white light emmission but needs to be ignited first. Mg is stored and used in air while Na is stored under oil to prevent reactionwith the atmosphere. A bit like yellow Phosphorus (which is stored under water) on the danger scale.