I got a couple of CAD designs you could use. I don’t have a 3D printer so I had to send one to a shop. Came out okay with some minor jank and adjusted the model afterwards, but not quite sure how the adjusted seat will play as I have yet to get it printed.
Sorry man, only done C sized! I had some spare flats and Center Tracs laying around so I designed the seats to fit C. I could give you the DXF for the C seat and make adjustments so it fits D
Might be worth posting in a couple of the CAD or 3D printing threads. I remember seeing a few things in there that might be of interest and maybe someone has a bearing seat library or a source for metal inserts that would act as them (like the Cabal and other systems).
With a wood yoyo would you actually need the response to be handled by the spacer?
I don’t know much about wood, but would you have to worry about the wood absorbing flowable silicone or the adhesive from pads? Cleaning out old pad residue also doesn’t seem like it would be fun since I don’t think you’d want to rub an alcohol solvent against wood?
If the goal is to use response pads, I think the spacer would need to house the pad recess as well. It seems like it would be much easier to create the wood halves accurately with fewer b grades.
I know this may not be an answer you’re looking for, but it could be a solution. You could always make your own custom toosl to create the groove. Harbor Freight sells tiny HSS bar stock for making your own tooling. I’ve used it to make small turning tools for really detailed work. A miniature “hook” / hollowing tool out of the flat stock is perfectly sized for creating the groove. I’ve made a tiny bowl hollowing tool out of it and it’d totally work the same. Link to the bar stock - It’s good stuff. Most turning tools are made of HSS. It holds a great edge.
If that’s not an option, if you have a parting tool, usually it’s tip is similar sized to a response groove pad.
@cowmamba that’s a good idea. My concern is the level of precision and accuracy required to avoid a bunch of duds. I think the margin of error would be easier to control with pre-machined metal. I also have to wonder how humidity changes could affect the fit over time. But Eric Wolfe has apparently done it, so it’s definitely possible