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Hey guys. Please advise what is the proper way to attached the tube ring to the dovetail plate.
Orion 100mm Tube Ring on 8" Dovetail Plate:
Am I suppose to screw the middle screw all the way in very tight until both washers are pressed flat against the screw head? What to do with the other 2 screws from the plate? Screw in all the way also to press against the tube ring base to prevent the it from spinning?
The 100mm tube rings are 6mm longer than my tube. A 90mm ring is too small for my 90mm refractor. According the the tube ring product page, I am suppose to "shim with extra felt". How do I do that and what is the best way to do so without damaging the oringal felt in case I want to go back to 100mm diameter? Thanks!
You should used the 2nos. (on bothsides. don't use the centre screw) screw so that when all tightened, it will be flush then you could slide it to your mount.
hi Gary
Did you get the tube rings from Astrobargains? I assume they're open now?
I need rings for my 100ED... (the plywood rings aren't working out, translation, they're butt-ugly)
"Shim with extra felt" -- buy some of the felt from the DIY Shop that is used to cover the bottom of furniture? (not the teflon ones, which cost more, but the cheapest ones). You can trim and stack them (3 shims on each ring should keep the tube centered) but they may stick to the existing felt. Personally I wouldn't care if the existing felt got marred.. it's just felt.
Gary wrote:Hey guys. Please advise what is the proper way to attached the tube ring to the dovetail plate.
Orion 100mm Tube Ring on 8" Dovetail Plate:
Am I suppose to screw the middle screw all the way in very tight until both washers are pressed flat against the screw head? What to do with the other 2 screws from the plate? Screw in all the way also to press against the tube ring base to prevent the it from spinning?
Yes. But don't tighten initially. Mount the tube-ring to your OTA first, then adjust the tube-ring so that both tube-ring firmly and properly mount on the OTA. Then you tighten the screws tightly.
Gary wrote:
The 100mm tube rings are 6mm longer than my tube. A 90mm ring is too small for my 90mm refractor. According the the tube ring product page, I am suppose to "shim with extra felt". How do I do that and what is the best way to do so without damaging the oringal felt in case I want to go back to 100mm diameter? Thanks!
Do you mean the tube-ring is larger than your OTA?? My current tube ring is also larger than my OTA by a bit. To solve this problem, I use unprimed canvas to cover around my OTA, so that my tube-ring can hold onto it firmly. Please note that the unprimed canvas have less fiction on aluminium OTA, so it might slip a bit if you don't tighten the tube-ring. Some might feel that this is a bit dangerous, but I consider this as an advantage for me as I can easily rotate my Newtonian inside the tube-ring. Also, dew don't form easily on the rough surface of the unprimed canvas.
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
Hi guys. Thanks for the advice. Appreciate it. Will give your suggestions a try. Just bought a set of screw and nuts from a nearby hardware store to replace the original ones for only $1.60. These new ones can be tighten easily with a screw driver. So using these together with the original washers.
@Orly: Ya. Bought from AstroBargains. They are open already. Their main homepage has also been slightly updated.
@roma: Don't really get what you meant. There is only one center hole in the flat base of the tube ring. If the center screw is not used at all, how to hold both pieces of metal together?
Not too sure from your pic, but seems you have a Tube ring that is wider than the top part of you dovetail, hence the space inbetween them! And the tube rings only have One threaded hole to screw into from your dovetail.
If so, that center screw should be able to hold the tube ring and have it's head flushed into the dovetail tight? So yah tighten till the 2 washers clamp shut. You don't need the 2 screws unless the tube rings have to threaded holes that match up! And shouldn't spin as you have the tube rings on your scope which is fixed to the dovetail...how to spin?? hehe!
If anything,...you could get some extra washers to fill in the space in between. As long as your center bolt is long enough and has enough threads into the tube and dovetail...all should be good! If you get the Felt you could also use some to sandwhich in between the dovetail and tube ring for some grip! Or maybe small wood shim to fill that gap to act as a washer? If you do use the 2 screws either side for friction,..don't tighten too hard! Cos it will be pushing against the tube ring and center bolts force!
You could in the future try to get Stainless Steel HEx Head Bolts which you can tighten with an Allen Key. More positive tightening with a Hex head!
Hope that helps!!
My wife never complained about how much time, effort & money I spent on my Astronomy hobby!................suddenly I met her!!!
Thanks for the ideas! Ya, its wider than dovetail so got space inbetween. Saw some dude in other forums sawing off part of the dovetail to remove the space. Sorry about the spinning description. I meant without the scope, one tube ring turning around the center screw (assuming the center screw need not be tighten).
HAHA...np Bro...Spin away then!! As long as your center bolt has enough threads running through the hole on the Tube ring,..you have a good anchor!
As Orly mentioned,...glue some felt, layer of needed...but not to thick though as it would become a cushion more than a grip! And the glue can clean with WD40!!
When you say 6mm longer than tube....6mm gap all around the tube or 6mm total?
My wife never complained about how much time, effort & money I spent on my Astronomy hobby!................suddenly I met her!!!
"The universe is composed mainly of hydrogen and ignorance." 
