Mike

Why not cut a 4" diameter piece and drill to suit fixing to the chuck with c/s head screws and then drill to screw to the table tee slots using longer than normal tee nut pieces.

You can use separate pieces for locating the chuck register and to provide an arbor to locate the table centre.

Emgee

Edited By Emgee on 15/03/2022 20:59:49

spelling corrections

Edited By Emgee on 15/03/2022 21:01:39

Hi Mike

You will be screwing the plate to the chuck and all will be as one unit as the table,plate and chuck all make contact, If it didn't work out to be rigid enough you can always double up the plate.

Emgee

Hi MikeK, nothing wrong with welding steel plate, but you will be wasting money trying to stress relive it in your oven, assuming you are talking about a domestic oven, as it won't get hot enough. Stress relieving steel starts at around 600 C.

Regards Nick.

Couple of things going on here:

1. Mild-steel versus Cast-iron. In theory cast-iron is better for this application because it absorbs vibration, whereas steel 'rings'.
2. There's a risk welding will deform a plate made by joining bits mild-steel together, especially if the welder is semi-skilled. Distortion is hard to correct if it happens.

In practice, I doubt the difference between dead cast-iron and ringing steel matters much on a Rotary Table.

Making the plate from a lump of metal big enough in the first place rather than welding avoids the risk and the cost of fixing it if it goes wrong. If welding goes well, Mike will save money. If it goes very badly, a waste of time and money. Mild distortion might not be difficult to fix, so another win. The method is unreliable.

Problem with a heat-warped precision item is how to fix it. A domestic oven isn't hot enough because relief soaking requires higher temperatures for several hours. Heating with a torch requires judgement. The warped item could be machined to shape, but it might move again due to stress relief. Certainly not impossible, but more unpredictable than I care for.

Have to confess I'm partly negative because I don't enjoy this type of problem solving and would rather buy my way out of trouble by paying for a suitable cast-iron or mild-steel disc. Others would relish the challenge and delight in the experience. I don't think there's a straightforward answer. It comes down to what Mike has to hand and his appetite for adventure. Be good to know how it works out, dazzling triumph, miserable failure, or 'good enough'!

Dave

MikeK:

I would encourage you to try the weldment approach. Here is one I made to rescue a condemned hobby drill press:

Rough turning the disc and tube allows easy vee joint preparation and after welding the result is re-machined (mine hasn't quite cleaned up).