Hi POI, Being an Australian built Victa I guess the roller would have been plain old blue gum, but if you were after something a bit flash it could be made from red gum. Diameter not sure but probably around the 60mm
POI, Look up a local wood turning club/guild and somebody there will make one for you, they are always looking for something different to make, you can only turn up so many bowls and lidded containers before you get sick of them
Hi POI No idea they are a white wood of some sort that is fairly soft. If I need wooden rollers for a restoration I have stock of Norfolk Island Pine from one I cut down on my yard. I find that it is easy to turn and looks the part when oiled up and I have had no problems with it splitting.