What are these stone sticks?

I picked up a tobacco tin of BA taps a few weeks ago at a boot sale, which aren't a full set but are in really decent nick- paid a quid but was then given several other tins of rusty taps, drills, and another tin with what look like marble but feel like chalk- some kind of stone sticks?

I wondered if these were hard and could polish up the tip of a drill, or the flute of a tap, but they feel soft and chalky... about 5/16-1/2" in section if that helps?!

Any thoughts?

Have a look at Washita and Arkansas stones and see if they fit what you have.

Mike

Hi Richard,

It is chalk ! Actually its called "French Chalk" and it is usually used for writing on steelwork, often powered and used when mending punctures in your bike tyres tube, to stop the glue sticking to the inside of the tyre.

Edited By John Baron on 06/08/2017 21:14:46

Water of Ayr Stone, used by jewellers to polish after soldering.

John

Well that's three apparently different answers for a start!

But seriously, thanks, I'll start googling with at least some sensible words now- the suggestions above all seem very plausible from a 10 second Google on each!

Just rub one on a bit of fine sandpaper or file If it produces fine white powder even more easily than blackboard chalk then it is French chalk. Given the quantity and inclusion with engineering tools rather than cyclists spanners I would guess a polishing stone is a distinct possibility.

Hi RichardN, it is known as "French Chalk " and is usually used in the "heavy" ( Blacksmiths) engineering world to mark out work that does not need the precision that lathe and milling machines need , the end of the chalk is usually ground to a sharp point.

Water of Ayr stone. It looks like french chalk sticks but harder. I also have some in a tin. Used it long ago for removing very light blemishes from copper and aluminium.

French chalk can be rubbed onto files to stop pinning.

Andrew

Another vote for French chalk. I have a pack of it I bought for marking hot metal.

Looks to me like Soap stone, used to mark up steel plate etc.

Clive

An interesting side fact about soap stone [which is also my vote for these sticks] is that when it is heated and allowed to cool it is then hard, water resistant and resistant to wear. A useful property for fashioning low voltage electrical fittings, soft for easy working and durable when hard.

​We used to use it for underwater light fittings to hold halogen bulbs around pipe cameras in submerged work.

Regards Brian

So can ordinary chalk. (English chalk??)

Looks like talc to me. I was brought up to call the solid talc, and the powdered form French Chalk. I think it's a magnesium compound, unlike ordinary chalk which is calcium carbonate. Blackboard chalk is actually calcium sulphate (gypsum, Plaster of Paris).

George

I thought I was the only one.........

The guy changing tyres at the classic bike races looked at me like I was stupid when I mentioned grating talc on the tubes.......... he said, "No... use french chalk" in a very worried tone....

Definately talc, otherwise known as French chalk. It is mined near Luzenac 1800m up in the Pyrenees in southern France.

I visited the talc mine there last year. It is one of the world's biggest talc mines and is an open cast mine on a massive scale. Well worth a visit if you are anywhere near. A video on Imerys Talc website shows the scale of the mining operation.

Talc has a very wide range of uses apart from stopping files pinning when filing aluminium and using on baby's bottoms.

Russell

+1 for 'French Chalk', always keep a piece in my workshop coat pocket for rubbing on files when filing aluminium... & for rubbing on drill shanks when I can't read the impressed size.

George.

This is the composition of common talc, Mg3Si4O10(OH)2, and this is for Crysotile asbestos, Mg3Si2O5(OH)4. Both are usually mined next to each other and despite reassurances to the contrary I wont have it anywhere near me.

Difficult to avoid Fizzy. It's an ingredient in lots of food and pharmaceutical products. It's in papers, paints, and plastics.

Russell