Easy method of 4 jaw centering

[HopperParticipant @hopper]

Posted by Gary Wooding on 02/09/2020 10:25:59:

Posted by Hopper on 01/09/2020 22:55:40:

 

It's not my way. I saw it published in MEW about 2 or 3 years ago. Can't remember the author's name. A Scandinavian chap maybe. He described it more clearly with illustrations.

In that case it's not surprising 'cos I wrote the MEW article you saw. My link was the actual article.

Lol. Small world. And not even close to Scandinavia!

But thanks for the tip. Brilliant in its simplicity.

Edited By Hopper on 02/09/2020 10:31:32

[Henry BrownParticipant @henrybrown95529]

It seems we all agree practice makes perfect but don't forget you need two readings for rounds – preferably diameter and face or two readings on the diameter(s) as far apart as possible.

I always prefer the dti on the top of the job tightening the jaw nearest the dti and have never needed two chuck keys – probably because the machines I have used are guarded and too large to reach the second one.

For roughing from stock I set by eye, the tool will soon show if its too far out!

[Anonymous]

I'm with Henry. For rough alignment (and castings) I simply align by eye on the tool. If I need better accuracy I'll use a feeler gauge between tool and work. For yet better accuracy I use a DTI on the top of the work (easy to read) and adjust the jaw at the top, spin 180° and adjust again, and the same for the other pair of jaws. I only use one chuck key; I wouldn't be able to access the bottom jaw, my chuck is fairly large, work is normally heavy and the workshop gorilla does things up tight such that I couldn't loosen a jaw single handed.

For the few times that I need to pick up on a centre pop (which happens to be the current job) I use a wobbler:

Andrew

[Neil WyattModerator @neilwyatt]

My cheat for square stock…

1 Wind the tool in to graze work on one side, then move apron to right so tool clear.

2 Rotate 180 degrees, move tool back if it hits end of work move the tool out and go to 1

3 Is tool just grazing work? Yes – job close enough for jazz, now repeat for the other pair of jaws. No go to 4

4 Move the tool in half the distance then adjust jaws so the tool just grazes the work, go to 2.

Sounds a bit clumsy, but it gets close enough for most work.

[Author]

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