welcome back to the forum. I see you've been gone a spell.

that is a very vague question: photos of the two chairs side-by-side
would help. maybe a common object in the photo to show size reference.
also, what are your skills and tools available ??

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with just your description, I am thinking that you do not have the black
metal ring nor the wood seat parts ??
how about the rest of the frame ?
a person with a lathe could turn it to match the one shown in your photo,
add some buttons, and paint the ring black and clear the center seat.
the assembly would be up to you to figure out the mounting mechanisms.

or if you have the ring, and all you want to do is replace the center wood seat,
and the wood just sits under the lip, you could use a piece of quality plywood,
cut it out with a jig saw, and stain it to match the existing.

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Seats of the ice cream parlor chairs were usually a good grade of 1/4" or 3/8" ply (no thicker for flexibility). Rabbet the edge (with a router), sand and stain to match.

How thick is the existing seat? Make the replacement the same. Take it apart and let us see it nekkie. LOL

 

I would use the 3/4" cherry hardwood.
Rabbet the sides as Mark has said, then round off the top edge by hand.

 

LRM: you got mad cad skills to whip out that 3d perspective! (Useta teach AutoCAD - en espanol!)

 

LRM: you got mad cad skills to whip out that 3d perspective!

- Madmark2

Sketchup, took about two minutes.

 

Takes forever to rotate and set 3d lighting. 2d plan drawings rule the day! LOL

 

Karen doesn't want to replace the wood centerpiece, she wants to recreate the iron ring in wood because she has a chair missing that piece.

 

The RING! Ahhh, that's something different.

The original maker used metal for a reason. The expansion (tensile) forces on a segmented seat ring will tend to blow it apart. A solid piece of ply goods doesn't have a lip. A solid board will crack on the grain line.

Metal was used because metal was called for. Even if you could figure a way to turn this bowl (rimmed dish?) so it will hold it will be so big and bulky it will be, as they say in the trade, fugly!

 

this must be a pretty common item. a quick google search for "vintage child's café chair"
turned up several identical chairs selling from 30-$75 on the auction markets.
a person could actually hunt for "that bargain" and purchase one cheaper than having
one repaired (IF it is not a family heirloom, etc.). and all of them say "child's play set".

according to the O/P, the dimensions indicate this is only
a child's play set - or just ornamental. not actually having heavy people sit on it.
so there are many options to consider. but, if it were my project, I would probably look for
a parts donor on E-Bay. then all the chairs would be visually original.
a 10" disk can easily be turned on a lathe.

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