squaring the ends

[tanii51]

how do you go about squaring the ends on a rectangular block
3 jaw .or.. 4 jaw and how do you get it square to the chuck???

[BenM78]

Use the 4 jaw and face off the block. Turn the block around and either use a parallel to get the newly faced side parallel to the face of the chuck or reverse the jaws and set the machined surface to the back of a jaw segment.

A picture may help! I know this is round, but same principle for getting parallel faces.

http://images.benandmichelle.net/albums/userpics/fuelcap07.JPG

To do the next pair of faces set up again in the 4 jaw using a square to get the existing parallel face square to the chuck and slightly off the back of the jaws, then machine and flip again, set flush to back of jaws on the second side. For the final pair of sides it should pull up square in the chuck itself but it is a good idea to check. All 6 faces will then be parallel and square.

Remember that the outside edges of the rectangular block will give a big intermittent cut so you should use HSS not carbide tooling and a slower feed rate to lessen the impact on the tooling/lathe.

[Keith_W]

Hi tanni51,
If your rectangular block is parallel on the sides then use a 4 jaw independant chuck, then just face the end. Take out of chuck, turn arround and face end to required length. Clean up machined ends in vice with fine file and sandpaper.
If you dont want marks holding parallel sides use some used sandpaper between job and chuck jaws.

Regards,
Keith.