Nylon Screws for a 1.25" diagonal ?

[Northern Soul man]

Hi To All, wonder if any of you can help me - I'm looking to change the metal threaded screws which hold the EP in place in my 1.25" Diagonal which came with the Celestron 127 Mak, the tube which fits into the end of the Mak on the diagonal is already marred due to turning it when observing in different areas of the sky.

Wonder if anyone has measured the diameter and the thread pitch of these metal screws with the intention of replacing them with EP barrel friendly Nylon/plastic ones.

I've looked at the business end of the diagonal -  there's no way to insert a brass compression ring as there is no recess, would be great if you could just buy a replacement sleeve which screws directly into the top of the diagonal with a compression ring fitted - don't think they are available, would be a lot cheaper than a complete diagonal.

Would be interested if anyone has the diameter and thread pitch needed, also if there are any retailers - please chip in.

There is an adapter available for the Skywatcher 127 Mak I think to allow for the use of SCT Diagonals, but can't find any adapter for the Celestron 127 Mak - also if anyone knows of any retailers that will supply such adapter for the Celestron equivalent - please chip in.

Thanks to all in Advance.

Paul.

[coulthamst]

Most telescope suppliers use metric threads exclusively, and both Celestron and Skywatcher certainly do. Those on your diagonal will be either 3mm or 4mm diameter. You should be able to measure the thread diameter to distinguish between these sizes, and appropriate thumb screws can be ordered in packs of 10 from such as Ebay and Amazon at quite a reasonable cost.

[Northern Soul man]

Hi Jim, Thanks very much, I've been down my dads and he's checked the sizes for me - there's two sizes, 1 which holds the diagonal in the actual mouth of the scope (M4) and the ones which are on the top of the diagonal which secure the EP in place (M3) - I've took your advice and ordered some from off the well known Auction site - I think its much cheaper than ordering a new diagonal with compression rings, I think the supplied Diagonals are ok, I've checked them against my 2" WO Dielectric in the CPC 1100 and I think the extra "light grasp" is probably due to the extra aperture of the diagonal ( "2 compared to the smaller 1.25") - see how it goes, the scope side of the diagonal is already marred, but I have the Celestron diagonal which came with the 1100, so may just swap it over.

I'll post when the Nylon Screws arrive and I've got them fitted - I think they will be ok though.

Thanks jim and Regards

Paul.

[Northern Soul man]

Just an update, the M3 and M4 Thumb screws arrived today, were fitted, cut to size and checked with the hefty Aspheric EP, all good, they're going to be a good addition to the back of the little 127 Mak so I can use my more expensive EP's in the scope and not have to worry about ruining the EP barrels - done up nice and secure to hold the EP in place - just to re - cap - the M3 Thumbscrews fir the EP side of the diagonal and the M4 Thumbscrews fit where the diagonal enters the back of the scope - alls well.

Paul.

[damnut]

Hi Paul,

I would be concerned about the wear on the nylon thread and thus loosing your eyepieces out of the diagonal!

[Northern Soul man]

Hi Damian, Thanks mate - I ordered 10 in a pack of each size and only looking at using the Hyperions in there - I usually just use a set of Meade 4000 Plossl's in the Mak due to their size - initial looks at the Thumbscrews seem that they are quite "hard" I've cut them down to length, tried the 31mm Aspheric in the diagonal and it seems to hold very well with no wobbling present, but as you say they may wear after continued use, will just have to keep an eye on the back of the scope, I have it on a CG5 EQ mount, so as I move around the sky I will have to change orientation of the EP in the back of the scope slightly.

But will keep an eye on it and thanks for the post Damian.

If anyone else wants the sizes for their diagonals - The diagonal is the Celestron 1 1/4 #94115 - A (this diagonal uses M3 and M4)

                                                                                Also the Celestron Visual Back - 1 1/4 - 93653 - A.( this uses the M3 to hold the diagonal nearest to the scope)

As Mentioned you need to keep an eye on the EP once seated in the Diagonal and the need for the diagonal to rotate in the Visual Back - as with everything its trial and error - SO BE CAREFUL !

Paul.

[triton1]

I do believe you can get these screws in steel but with nylon tips can,t remember where though.

[Northern Soul man]

Nice 1 Jonn, would be nice to get the best of both worlds, with the metal thread holding securely and the nylon protecting our very very expensive EP's, you would think that the manufacturers would just use compression rings on all areas where contact between metals are going to scratch or mar due to contact.

I would like to think that the Nylon screws will hold secure enough not to worry - but as with everything you have to really make sure that these EP's are not going to fall out when you least expect it - I need to actually try out under the stars to make sure all is ok when in use, but just trying it on the bench with the Nylon screws done up securely seem to hold my Baader Aspheric 31mm well - its not "Click Lock" secure - there's no way I'm going to carry my Tube Assembly by its diagonal like you see from the Baader Click Lock advert.

Only time will tell.

Paul.