Square Centres?

[Alan Worland 1Participant @alanworland1]

Having a look for something today I came across some No1 dead centres which had been ground (accurately) into a now square point. The smallest of them has had the end reduced to about a quarter of an inch dia with the square ground on the tip.

What would they be used for? I have no idea!

 

Alan

[Alan Worland 1Participant @alanworland1]

[Engine BuilderParticipant @enginebuilder]

Could have been to turn a particular part that had a square recess at one end, between centres.

David

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hello again ,

 

This is a cutting centre . You will find references to them in old books on turning . In olden times the recommended method for making centres in the end of a bar for turning was to mark out and drill the ends with a small hole by hand . The work was then mounted in the lathe between one plain and one cutting centre whereon the cutting centre turned the original plain hole into a nice neat conical centre hole . Reverse ends to make another one and then swap cutting centre for an ordinary one and proceed with turning .

 

MW .

[Les Jones 1Participant @lesjones1]

I have had this one for years and wondered what it was used for.

Les.

[Sub MandrelParticipant @submandrel]

I’ve got one. It isn’t great but useful for centering something that won’t fit in a chuck easily.

 

Neil

[Alan Worland 1Participant @alanworland1]

Thanks for identifying these for me!

I (like you Les!) have had them for years and not had a clue what they were for but thought they might come in handy one day!

 

Alan

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