Square center

I wonder if someone could help me locate an MT2 "square centre" please?

Somewhere in a John Wilding article he mentions using one of these to drive a brass bob in the lathe, between centres, to finish the surfaces. I think it is like an ordinary fixed centre except that the end, rather than being a normal cone, is pyramidal, Thus, when pushed into a hole through the material, it formes little nicks in it which allow it to be driven. As long as cuts are light it should allow the cylindrical surface to be fully turned in one go. None of the "usual suspects" tool suppliers list them and I can't find any mention on Google.

TIA for any help!

A bit like one of these on ebay you mean?

Regards

Bill

I have one of these, it's meant to be used as a centring cutter, like a centre drill, not as a driving dog, but i applaud his ingenuity!

Neil

Bill, that's exactly it!! Thanks for looking (where I should have looked first). I have nabbed it.

John.

Maths obviously isn't the vendor's strong point. He had 5 when I posted, I nabbed one, as did you, and now he's only got 8 left if anyone else wants one.

Seems a good price.

Obviously the seller has had a busy morning grinding down the ends of a job lot of round ctrs so he can charge a premium for them

That's a little cynical don't you think? :P They'd have to be atleast machine ground - a hand ground job would look awful unless you spent a lot of time on it. I don't think he'd be too happy standing over a bench grinder all day neither!

Also to respond to tother post, the ebay system only lets you stipulate a set number, a lot of vendors just put any old quantity down as they're not expecting a flood of interest. 

Edited By Michael-w on 02/05/2017 16:32:30

Edited By Michael-w on 02/05/2017 16:33:40

"Square" centres were also used on hardened shafts to clean the hardening scaling off the previously centre drilled centres prior to grinding. After the "square" centres had been used, conventional cone centres would be used in the actual grinding operation.

Edited By Dinosaur Engineer on 02/05/2017 18:48:07

Along the same lines as the square centre to drive and centre the job and provide full access to the outer diameter you can get a centre called a face driver. If you ever wondered what the little chisel marks on the end face of a shaft were for it has probably been finish ground or even turned with a face drive centre. Google, face drive centre for CNC and it will show various types from spring loaded to hydraulic.

Mike

I just bought one too. New old stock ? Worth a punt for about a fiver with free postage.

I think mine was about a quid

N.

Ordered Monday, arrived yesterday, used today, job done! Good seller too.

Hardly. he charged £5.95 incl delivery. A standard MT2 centre from the site's favourite vendor is £3.98 plus delivery (plus VAT on the delivery charge)

Sounds about the same to me.

The same for me, a good purchase.