3-d printed scoring plugs?

[gnm]

Does anyone have STL files to print .22 and .177 scoring plugs/gauges?

Thank you.

[rgibson]

1845greyhounds (on this site) made some great 3-D printed outer scoring plugs for me. He received some questions about the construction (on this site) and replied that he found it necessary to add additional operations to surfaces to provide accurate scoring surfaces. Sounds like it was not a print and score situation. I miked the ones I bought from him and they were in spec with rulebook.

[northstar]

What is a “scoring plug”. Just learning this sport myself. Thanks Take care

[Ramon OP]

See it in action here https://youtube.com/shorts/HpfSBeHUFkU?feature=share

[rgibson]

A device used on paper targets to check a shot too close to “eyeball” whether it is touching the scoring ring of the next higher value to see if the shot receives the higher value. “Inner Plugs” are used to check most targets while “outer plugs are used for small bulls shot at 10m and 50 ft. There is a description of use in the NRA Smallbore Rulebook

[pdeal]

3d printing by itself isn’t precise enough for this application. The diameters on a scoring plug should be within.001” or so and the edges need to be tight corners.

[rgibson]

Jamie had to add several extra steps to finish these plugs after printing. This was covered in depth in an earlier post. I have three and they are in spec as I mic them. He may have found them too much trouble to continue making. Since I am scoring paper USA50s I use them or my metal ones but I prefer the printed one because the handle is bigger.

[1845greyhounds]

In my experience, FDM 3d printing alone is not accurate enough to make score plugs. I only have experience with FDM printing, but RESIN 3d printing MIGHT be accurate enough...

The USA50 score plugs I made and sold were FDM 3d printed a few thousands oversize and then formed/cut down to size using the following methods. The 0.2225 - 0.2240" plug section was thermo-formed by spinning a precision drill guide bushing over the printed PLA plastic plug. The friction created adequate heat to lightly melt the plastic and shape it into the correct size with very low TIR. Then I concentrically cut the 0.3535 - 0.3555" shoulder relative to the 0.223" plug surface with a 3d printed fixture that held a chisel blade. Finally, a "USA50" ID cap was glued onto the handle. The ID caps were printed with a smaller nozzle to produce legible text. For all printing steps, I'd print 64 at a time to maximize printing efficiency, while maintaining the ability to selectively abandon failed prints within my printer's controls.

Was it all worth it? I think so. I needed a USA50 score plug and none were available elsewhere. I had hoped to sell more plugs than I did... I certainly didn't make any money, but I gained a lot of 3d printing experience and knowledge that has helped me with other projects. I still have lots of USA50 plugs and a few A36 plugs if anyone is interested... (PM me). Attached are pictures of the parts, tools, and scoring instructions I made.