HELP! EQ6R-Pro internal threads damaged

[cfinn]

Hi all,

I have had a complete disaster with my EQ6R-Pro this week. I was attaching it to the Sky-Watcher Pillar Mount and managed to screw on the adaptor to the base of the mount at a slightly wonky angle. As a result I could not unscrew the adaptor - it would not budge! The screw knob itself came off in the effort of trying to unscrew it and I was just left with the bolt sticking out the bottom. Eventually I got it off with a pair of pliers but it took considerable force and it has completely stripped the internal threads as can be seen in the pictures below. These are now damaged beyond repair and I cannot attach the mount to the tripod or the pillar at all! The mount is essentially useless unless I can find some way to fix this 😟

Does anyone have any ideas? I think the only way to rectify this is to have the base re-engineered. I have contacted Optical Vision about repair but I am not too hopeful.

Thanks,

Charles

[ONIKKINEN]

You can try re-tapping the thread with a thread tap of the right size. Im not certain but i think these are 3/8 inch photothreads.

I would start with a thread file to try and clean what remains of the thread. Start from the back where the threads are most likely still in decent condition. Clean up the thread with the thread file as much as possible before trying to re-tap. Then try to carefully go along the same path where the thread used to be, or you will just end up destroying more of it. It will never be the same again with retapped threads of the same size since a lot of the material was lost, but it could work if you dont use too much force when threading into the mount again.

There are also thread inserts that you could try to drill into the existing hole but this i wouldn't try myself if i wasn't comfortable with this kind of thing.

The thread file and a thread tap + wrench will cost you not that much, but isn't guaranteed to work. But also probably wont make things worse. The best bet would be to take the mount to a local machine shop and ask them about refitting a threaded insert to the hole. Its not a huge ordeal and probably not that expensive. Its far from completely destroyed so entirely fixable.

[cfinn]

13 minutes ago, ONIKKINEN said:

You can try re-tapping the thread with a thread tap of the right size. Im not certain but i think these are 3/8 inch photothreads.

I would start with a thread file to try and clean what remains of the thread. Start from the back where the threads are most likely still in decent condition. Clean up the thread with the thread file as much as possible before trying to re-tap. Then try to carefully go along the same path where the thread used to be, or you will just end up destroying more of it. It will never be the same again with retapped threads of the same size since a lot of the material was lost, but it could work if you dont use too much force when threading into the mount again.

There are also thread inserts that you could try to drill into the existing hole but this i wouldn't try myself if i wasn't comfortable with this kind of thing.

The thread file and a thread tap + wrench will cost you not that much, but isn't guaranteed to work. But also probably wont make things worse. The best bet would be to take the mount to a local machine shop and ask them about refitting a threaded insert to the hole. Its not a huge ordeal and probably not that expensive. Its far from completely destroyed so entirely fixable.

Thank you so much for your reply. I think taking it to a local machine shop is the best plan. I found this place near me. It was just knowing what to search for!

Many thanks again.

Charles

[david_taurus83]

If its the same as the AZEQ6 then its M12. It looks like it's only the bottom 4 threads that are damaged so not the end of the world. Id try and remove the mount from the wedge and send an M12 tap down from the top end all the way through the damaged bottom end to clean it out.

[ONIKKINEN]

3 minutes ago, cfinn said:

Thank you so much for your reply. I think taking it to a local machine shop is the best plan. I found this place near me. It was just knowing what to search for!

Many thanks again.

Charles

Take the intact tripod bolt with you to the shop and ask them to re-thread with the same threads as the bolt to make sure the correct threads are applied, as @david_taurus83 said it is probably an M12 metric thread.

[Budgie1]

Re-tap from the top would be my first option, with a longer bolt to take advantage of the good threads. I would also run a thread chaser die down the that bolt, if you want to use it again, just to make sure there's no aluminium left in the threads which will catch in the mount thread and cause it to lock up again.

If the threads are totally shot, you can ask the engineering firm to "Helicoil" it back to the standard size.

This involves drilling out the old thread and re-tapping the hole to take a threaded insert with a M12x1.75 internal thread (assuming it's M12). You can get Helicoil kits from the likes of ScrewFix.

[cfinn]

13 hours ago, Budgie1 said:

Re-tap from the top would be my first option, with a longer bolt to take advantage of the good threads. I would also run a thread chaser die down the that bolt, if you want to use it again, just to make sure there's no aluminium left in the threads which will catch in the mount thread and cause it to lock up again.

If the threads are totally shot, you can ask the engineering firm to "Helicoil" it back to the standard size.

This involves drilling out the old thread and re-tapping the hole to take a threaded insert with a M12x1.75 internal thread (assuming it's M12). You can get Helicoil kits from the likes of ScrewFix.

Thank you!