Machining inside of Tube Rings

[Macavity]

I have a couple of instances where standard Skywatcher Tube Rings are just a *little* too small! And yes, I have removed the felt linings. But a general "workshop" type question: Is there a technique, where a machinist (machine) could "shave" a bit (1-2mm) off the inside of rings?

The standard rings almost fit a MAK150 OTA, but it is just that bit larger than their 6" Newt tubes. Imagining my tame (good sport) CNC machinist and preempting that "sharp intake of breath"...

[Astrobits]

It shouldn't be a problem for someone with a suitable lathe. I don't know if mine would be big enough, depends on the design and size of the bits outside of the rings themselves.

nigel

[Peter Drew]

Not a problem with a suitable size lathe. If you fit the tube rings with a short piece of tube they can then be clamped to a faceplate and the tube centered. The tube is then removed to allow for machining of the rings to the new size.

[Macavity]

Thanks for the useful ideas! The standard rings do screw closed - Around a "GOLD" MAK150, but ideally I would like to gain ~6mm in circumference (just 2mm diameter) to get normal / better closure. Maybe a bit more to add some NEW thin felt / velour.

In case anyone was wondering: I use a pair of Skywatcher (ST)102 rings to fix a pair

of homebrew (power and USB) "hubs" either side of a Skywatcher Pillar mount.

[fwm891]

A faceplate is the obvious route. Watch at the hinge points that things don't get too thin!

[lennylovit]

4 jaw chuck and "clock" it to find center, easy, and put some form of spacer "2-3mm" to hold the clamp open a bit so when turned out to size you will still have a bit to pull tight on the scope

Lenny