Q : What is "blanchard grinding"

[josephc]

Maybe it's a dumb question but can someone tell me what is meant by blanchard ground (as in a 12" X 12" blanchard ground plate) ?

Thanks
JC

[BillH]

Like a surface grinder except it has a vertical axis spindle. Usually very big machines.

[This message has been edited by BillH (edited 06-30-2005).]

[josephc]

Thanks !!!

[Chief Mcgee]

http://www.commercegrinding.com/300inch.html

[John Stevenson]

Side note:

Known as blanchard grinders in the US as they are made by Blanchard.

Known as Lumsden grinders in the UK as again this is the UK maker.
No difference, same operation.

John S.

[Norman Atkinson]

Phew! I thought that the dreaded aluminium pans had got me. Lumsden- Gateshead- not there any more- we were shareholders- once did a Myford up on one.

Are there any left- for a ten minute job in the North of England somewhere?

Have lathe bed, will travel.

Norman

[IOWOLF]

I ran a blanchard at Vickers Omaha plant, easy job,vane pump rotors had to be +/-.00003

[Chief Mcgee]

I have always heard that Blanchard grinding could produce the flattest surface. Had a customer bring me several plates to surface grind on one side. (6 x 18 surface grinder) Gave me fits until I realized that the Blanchard ground side had a concave to it. I know the grinding head tilts from side to side. How do you know when it is flat? Thanks

[crossthreaded]

Chief Mcgee,we used them in optics Fab, in the last Century. You test the flatness of the work with a spherometer, to measure the depth. You can also give the piece a fast "polish" to use an optical flat or interferometer. The real Blanchard grinders were for flat work, but folks seamed to refer to any "generator" as a Blanchard. My boss once said they would hold a few fringes from flat (1 fringe is .000025inch) from flat

[josephc]

Thanks for all the replies - much appreciated...