Cobra f8 Adapter Install Issue

I got an adapter free from a friend after a shaft broke off near the top of the adapter. I drilled it out, hit it with the honing bit and assumed I was good to go for install but for some reason I cannot get the shaft (Tensei Pro Orange) to go more than a 1/2 inch into the adapter. Does anyone have any thoughts? I’ve done plenty of club building and adapter installs but this one has me totally stumped. The interior truly looks completely cleaned out.

I've never had an issue with Cobra adapters. Is it possible there is still some epoxy bonded to the inside but just polished so that it looks clean?

Stick a tee in the adapter and measure how far in it goes. If it's less than 1 1/4 of an inch, you likely still have epoxy in there. IIRC, Cobra adapters are 1 1/4" insertion depth.

Are you trying to re-install the shaft that broke - or a different (undamaged) shaft?

If it's the one that broke, the breakage resulted in you running out of parallel tip section for the install. It's not going in because the diameter of the shaft is getting larger before the full installation depth is reached. Which also means you've gone beyond the reinforced tip section of the shaft which basically makes it unusable for anything but things like - an alignment marker, a tomato stake, or driveway marker.

If it's a new shaft, it could be the tip prep isn't sufficient. Check the tip size in several spots with a calipers to make sure it really is down to .335.

Also visually inspect the inside of the adapter to look for any abnormalities. Not sure exactly what you used to clean it out but the ideal tool for cleaning a hosel is a hand reamer with the exact size of bore. That's the best way to make sure you've gotten out all the epoxy

e.g. Spiral Fluted Reamers

Sorry for the late responses. I figured out what was causing the issue. A small piece of the previous shaft did not break away when I was drilling it out but I could not see it no matter how I shined a light into the adapter. Unfortunately in my efforts to get this last piece out I drilled through the cap at the bottom and ruined the adapter. Not my best moment.

If all that's removed is the cap that prevents the epoxy from hitting the threads that's an easy fix. I've had caps come out with shaft pulls. Just cut a circular piece of masking tape or foil tape and cover the hole over the threads. You need to use a pencil or something to get it down the adapter but it should be doable.

I wish it was just that but I got a the top two threads as I went through. I was using a dremel for high RPM to try to get that last piece and it slipped right through.