We like to camp, mostly with the scouts and the pole ends for a Field Canopy had deteriorated due to UV light and harsh conditions of camping. I couldn't find replacements so I just designed and printed our own. I beefed them up from the original parts to ensure they held up. We'll see how long they last. They work great.
If you need replacement and have a different pole diameter, I don't see why these couldn't be scaled to fit your specific needs.
Measured pole diameter 48.41mm. Pole end max inside diameter 50mm.