Rotary Table

My question is how do you centre a rotary table up with with the centre of the spindle on a milling machine. Is there an easy way?

Thanks Paul.

Are you using it vertically or horizontally?

 

J

I have a ground bar which fits in the chuck/collets and i move the table into position and lock the bar in the jaws of the table, then nip the table down, alternatively i put a morse taper in the table with turned end and bring the chuck down onto that and then lock it.

 

Gets me near enough for what i do.

 

 

Brian

Brians way is the quickest and that the way i use most, an other way is to use a clock held in the spindle and rotate it round something held centraly in the table, another way is a co-axile indicator clock.

 

Stew

Paul

 

Have a look here for ideas

 

Sorry to keep plugging my website but having spent so much time establishing it I am keen for it to become well known.

 

Harold

Hi Paul,

Lining up the centre of the spindle with the centre of the table is not the same as centring the work piece on the table. I will assume that the axis of rotation of the rotary table is parallel to the X axis of the mill The first step is to align the axis of the rotary table with the axis is of the mill . Use a dial gauge in contact with the surface of the rotary table and adjust the position of the rotary table until there is no change in the dial gauge reading as the mill table is traversed in the Y direction. The second step is to centre the work piece on the table. I will assume your work piece is mounted in a four jaw chuck on the table. Use a dial gauge to centre the work piece by rotating the table and adjusting the jaws until the work piece is centred. (As you would with a 4 jaw chuck on a lathe.) If you rotary table allows you to disengage the worm then this makes it easier. The final step is to align the spindle with the axis of the rotary table. (I will assume you are doing something like cutting a key way in a shaft .) I will also assume that you have a DRO on your mill. Mount a plain piece of rod in the spindle collet.. Move the mill table in the Y direction until a feeler gauge is just pinched between the rod and one side of the work piece. Set the DRO to read zero. Repeat this on the other side of the work piece but this time note the DRO reading. Divide this value by 2 and move the Y axis until this reading is shown on the DRO.

I hope all my assumptions about what you are trying to do are correct.

 

Les.

Thanks for the replies. The problem is centring a disc in a 4 jaw chuck when non of it protrudes to be able to put a DTI gauge on it and no centre hole either to clock it up by.

Thinking back I cant think I would ever need to centre the middle of the rotary table with the centre of the spindle, just need to make sure the work piece is centred in the middle of the rotary table. I have a small 3 jaw self centring chuck but it is not big enough for what I am doing.

Paul try using the dti on the outside of the chuck jaws, just take care not to sock the DTI.

 

I have made a plug for my rotary table with a recessed point in the middle (upside down it fits the hole in my faceplate, which fits on the table). Eyeballing it to line up with a wiggler needle in the mill is accurate enough for may jobs. Another way is to push a dead centre into the hole in the table.

 

Neil

Hi Paul,

You could use a finger type dial gauge just touching the inside of the jaws. If you have a DRO or fit some kind of stop on the Y axis you could move the table so that the dial gauge did not touch the jaws while rotating the rotary table and move it back to the same position when the dial gauge was aligned with the jaws. IF ALL THE JAWS ARE THE SAME LENGTH then you could use the dial gauge against the outer edge of the jaws.

 

Sorry about my last reply. I gave suggestions for a vertically mounted table and I have just re read your post saying the question referred to a horizontally mounted table

 

Les.

Is anyone else a Lautard fan?

 

Lautard's Manouver:

 

Clamp down the rotary table and set it so its slots are at 45 degrees to the table slots.

 

Put an edge finder in the mill spindle. Position the mill table until the spindle is approximately on the X-centreline of the rotary table.

 

Lower the spindle and pick up the LH edge of the rotary table (moving the mill table in the X direction).

 

Raise the spindle and move the mill table L by half the rotary table diameter plus the CF diameter (call this total amount R).

 

Move the table in Y direction away from you by rather more than this, lower the spindle again and again pick up the rotary table edge moving the table only in Y. Move the mill table towards you by R.

 

Now pick up the LH table edge again and again move the table R to the left. Repeat in the Y direction again.

 

By this time the spindle will near as dammit over the table centre, but you could repeat the cycle again if you want.

 

This technique is useful if the table is already clamped and you want to centre it, and anyway can get as close as you want to exact centreing. It won't of course help center the work on the table!

 

This comes from "Machinist's Bedside Reader" by Guy Lautard, an excellent read (all 3 or 4 volumes).