To Mike Conder and anyone else that cares about this issue: I got my test prints of my coupler boxes from Shapeways Saturday (Feb, 17) and as I had surmised, they will need another pass at the drafting board and be made in another material than the one I first chose. The main problem, (as I anticipated) was that the coil spring wants to shift around and not stay centered. So I made a bit of an enclosure to hold the little buggers in place in my new design. The second problem was that the Nylon that Shapeways printed them in, is not nearly as high of a resolution as their web page would have you believe it is. The best resolution material that they have is still the Ultra or Extreme Detailed Frosted Resin Plastic. This stuff is far more brittle than the Nylon stuff to be sure. But, I've found that the Nylon stuff is almost impossible to drill and drill straight. And because of the printing limitations at Shapeways, any design for the Sharons's made by them, is going to have to have the pivot shaft drilled out for the mounting screw.

On another note though. After some fiddling around, I made a pretty important discovery. We don't really need a new coupler box design at all!!! What I found was this. If you use gel-super glue and super glue the coil spring to the back end of the Sharon coupler's shank and the shorten that spring appropriately. The whole lash-up will fit in the Accumate or Kadee 714 coupler boxes. You will also need a very short alignment pin at the back of the Kadee 714 box to slip the coil spring into. I also found that the 714 coil spring works better for this than the one supplied with the Sergent's Sharon's. IMHO, I think this discovery is a win/win for those wanting or needing a self-centering HOn3 Sharon coupler. It's less work and one less expense. Which means less time and money spent on this phase of rolling stock construction. As a side note here. From what I've found. Regardless of which way you go. The coil spring needs to be gel-super glued to the back end of the Sharon Coupler to get the self-centering effect.

Write me if you ave questions.

Dale Buxton

Dale:
Thank' for your update and research. 
The use of the Kadee the 714 coupler box seems very promising.  I will try it soon.

Mark Lewis 
Stony Point, NC 

Maybe. I was kind of thinking the same thing. Question is, do you make it to scale with a scale size buffer casting opening or do you make it to a 714 clone width opening? Hmmmmmm...

Ok gang, I have redesigned my Sharon coupler box and tested it extensively. I will post pictures later today. If there is interest in these I will sell them through the the Shapeways store program.

Dale Buxton 

Ok gang,

I put the coupler boxes up on Shapways Stores. You can find them at this URL:

https://www.shapeways.com/product/FX5CY5CBJ/hon3-spring-centering-sharon-coupler-box

I have made them available in a pack of 10. Shapeways wants $5.30 plus shipping for the 10-pack. I also drew up a 100-pack that would cost about $22.00 plus shipping if there becomes that much of a demand. Which I kind of doubt.  I will be making nothing on this. I did this only as a service to my fellow modelers. 

Dale Buxton

Here are some photos and a vid of the box and coupler in action. The boxes are in another material. Its translucent. This black material turned out to be quite brittle.

Dale Buxton