@lichfieldjohn use a big fender washer that fits on the inside of the broken piece. Epoxy that in. Get a bolt with the approximate same diameter as the previous threaded rod. Push that through and epoxy that in as well. You could even fill that broken part with something like epoxy resin. now with the bolt sticking through and firmly in place cut a slot on the bottom of the bolt where the thread ends. Make it big enough for a screwdriver the fit in. Use another fender washer that fits over the bolt and on the bottom of the broken part, that should sandwich the broken part in between two fender washers. You can then mount the pole through the base and reapply the pole to the base and attach a nut to it. The slot is to holt the bolt in place while you tighten the nut. Hope this makes sense.
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@lichfieldjohn use a big fender washer that fits on the inside of the broken piece. Epoxy that in. Get a bolt with the approximate same diameter as the previous threaded rod. Push that through and epoxy that in as well. You could even fill that broken part with something like epoxy resin. now with the bolt sticking through and firmly in place cut a slot on the bottom of the bolt where the thread ends. Make it big enough for a screwdriver the fit in. Use another fender washer that fits over the bolt and on the bottom of the broken part, that should sandwich the broken part in between two fender washers. You can then mount the pole through the base and reapply the pole to the base and attach a nut to it. The slot you cut in the bottom of the bolt, is to hold the bolt in place while you tighten the nut. Hope this makes sense.
@lichfieldjohn use a big fender washer that fits on the inside of the broken piece. Epoxy that in. Get a bolt with the approximate same diameter as the previous threaded rod. Push that through and epoxy that in as well. You could even fill that broken part with something like epoxy resin. now with the bolt sticking through and firmly in place cut a slot on the bottom of the bolt where the thread ends. Make it big enough for a screwdriver the fit in. Use another fender washer that fits over the bolt and on the bottom of the broken part, that should sandwich the broken part in between two fender washers. You can then mount the pole through the base and reapply the pole to the base and attach a nut to it. The slot is to holt the bolt in place while you tighten the nut. Hope this makes sense.