T-adapter ring (not T-ring)

[Demonperformer]

Last night, I managed to destroy not one, but two pieces of equipment.

Firstly, my canon T-ring, which is easy enough to replace.

The other fits between the T-ring and the sct. On the meade instruction sheet in the (second hand) pack (a focal reducer) from which I got it, it is called a T-adapter ring. It has an outside thread on one side that screws into the inside thread of the T-ring.  On the other side, it has a sort of "floppy" ring that is threaded inside and this screws onto the sct.  This is the ring for which I have been totally unable to track down a supplier (although this could be because whatever I type into google, if it contains the word "adapter" and the letter "T", google insists I am after a standard T-ring rather than one of these).

Can anyone suggest a supplier who sells one of them?

Thanks.

[basically, I have managed to strip the threads where the two rings connect, making them (a) inseparable, but ( too loose to be of any use].

[jambouk]

Something like this?

http://www.firstlightoptics.com/adapters/celestron-sct-t-adapter.html

James

[JonC]

Think my Meade uses this one

http://www.rothervalleyoptics.co.uk/meade-64-t-adaptor.html

picked it up cheap on ebay. And yes the threads one them are pretty bad, any chance of cleaning the threads up with the correct tap / die?

[jambouk]

Meade:

http://www.harrisontelescopes.co.uk/acatalog/Meade__62_T_Adaptor_For_LX90_200.html

James

[Demonperformer]

Thanks, guys - spot on.

Have gone for the celestron one as this seems to be cheaper across the board.

Ordered from Telescope House, because I need a T-ring as well, and it was about half the price of the ones on FLO [they could be different make/quality ... don't know ... so may not be a valid direct comparison].

As I am virtually prevented from doing any imaging until they arrive, this should give at least a couple of crystal clear nights for those in the vicinity ... make the most of them ... you're welcome [through gritted teeth ]

[Demonperformer]

any chance of cleaning the threads up with the correct tap / die?

I suppose there could be, but I have already expended quite a bit of energy trying (failing) to get them apart. All I have achieved is some cuts on both my index fingers. Then I would have to get the correct tap/die to do the job and, being just as kak-handed as stripping the threads in the first place makes me sound, I'm not convinced I would do an even passable job.  All in all, I think life is too short ....

Thanks.

[jambouk]

Stick it all in the freezer and give it a tap with a rubber hammer after a couple of hours or over night, else bake it all in the oven for a but assuming no plastic. But as you say, new bits are coming so sit back and chill

[Demonperformer]

Well, I have nothing to lose. No freezer, but have put it right at the back of the fridge (the coldest bit) and will leave it for 24 hours and see what happens.

[Demonperformer]

Well, I can confirm that after leaving them in the fridge for 24+ hours, I took them out and tapped them and I do now indeed have two pieces. Unfortunately, they are not the two pieces with which I started.  The threaded portion of the T-ring separated from the rest of the T-ring and is still well-and-truly attached to the adapter. Ah well, I had nothing to lose by trying.

Have received two emails re the arrival of the new bits:

(1) Items over £30 will be sent by courier (signed for). All items under £30 [as this is] will be sent first class post.

(2) Your items will be delivered by courier on Tuesday, please make sure someone is in to sign for them.

[jambouk]

Pit the remaining two bits which are welded together in the oven at 200 degrees c for half an hour, then with oven gloves give them a tap and see if they unscrew.

[Demonperformer]

Well, that has made a difference.

The screw thread part of the T-ring has now become unstuck, and it is apparent that the threads have not actually been destroyed at all.  It would seem that the problem was actually the boundary between the threaded part of the T-ring and the rest of the T-ring.  So I now have three bits.  The original T-adaptor, that is back to its fully functional self, plus the two bits of the T-ring.  I have checked the nosepiece in the T-ring threads and it goes on/off without any difficulty.  Which means that all I need is some decent metal adhesive to fix the threaded part of the T-ring back in place and I will be back where I started - with the exception of getting a new set of rings arriving tomorrow.

In view of this, I may well set up a set for SLR/SCT connection permanently and use the others as I was previously.  This will mean less taking things apart and putting them back together again, which is probably a good thing in the circumstances.

Thanks.

[jambouk]

"They" say to put boot polish on the threads to stop them cold welding again in the future.

Heating in the oven often can change the colour of the anodising so it starts to look golden.

James

[Demonperformer]

Not quite what I was expecting, but my own fault for making assumptions.  I had assumed that the long bit that attaches to the camera was unscrewable, but it is just one piece, meaning that there is an additional distance of 5 cm between the scope and the camera. I'm not sure how much focussing distance there is on the sct, but two inches is an awful lot to have to move it, plus the instability introduced by having an additional two inches stuck out the back waving around in the breeze. All-in-all, very happy that I managed to separate the two original from the T-ring and it is now fully functional again.

Please note this is NOT a criticism of Tel House, who supplied precisely the bit I ordered, but of me failing to check the bit I ordered was precisely what I thought it was.

Comparison photos: L - what I was wanting, R - what I got

[Earl]

If your using the reducer and connecting to a DSLR  ( i think this is what your doing) is the spacing correct?

[Demonperformer]

No, I'm not using the reducer, just the adapter ring that came with the reducer, screwed into the T-ring.  [The instruction sheet that came with the reducer said that it can't be used with a DSLR due to vignetting.] This setup focussed quite easily (just a couple of turns compared to the focussing position for the eyepiece). But if I put an additional 50mm between the camera and the scope, this is likely to require a great deal more adjustment to achieve focus (if indeed I can achieve it at all).

[Earl]

Ah so a standard SCT to T adapter then, these do seem to come in varying lengths.