rharshberger
Well-Known Member
Printed this to quickly cut centering rings for T300 to 38mm MMT, for a uprated Big Daddy build. The template is designed to be used with a flush cutting router bit in a router table (bearing on tip), the two #8 screws are for eventual knobs and the two brads are to tack multiple CR blanks together to the template. The CR blanks are cut to about 3.25" square, and the template is attached with the brads to the stack of blanks then the outer diameter is sawed as close to the template as I can get using a bandsaw (a scrollsaw or coping saw would work too), then a hole saw was used to punch a 1.25" hole in the middle of the blanks, then its off to the router table to remove the excess. With a little sanding the ID of the CR the 38mm fit pretty snugly on the tube, the outer just required enough sanding to clean up the small burrs and the ID fit the T300 (Estes 3" airframe ) perfectly. One of the rings (bottom on the stack did come loose after machining the OD and evidently I got it back on the stack a bit off so it got tossed since the center hole was off center, I made 3 rings just in case this actually happened...and what do ya know it did! The material is Amazon Basics Natural PETG. Still having trouble with my printer so the print quality is not as good as I would like, and the bed was out of level a bit and caused a chamfered area near the bottom on one "side", which the bearing on the bit was thick enough to make up for the bad spot. Took about 6 hours to print the ring template, the CR took less than 15 minutes to make compared to the 30-45 minute they used to take the old way, and its much safer than the fly cutters I use.
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