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How would be the best, easiest, cheapest way to make two tubes adjustable? Answered

I need to get two small tubes (one slightly bigger then the other) and to have each hold a lens and be adjustable (rotationally)? That is, they rotate along the axis of the tube  (as if holding the two lens near one another and turning one).  I have several options and am not able to purchase anything at the moment (or  I'd get some small plastic piping that fit fairly well together).
Any ideas?



6 years ago

I've used paper tubes for optic lens holding.
A shipping store if you have them in the east will carry some immediate
tubes. . . . . . .   A

Thanks, I will have to see if I can find anything that small. I need to hold (I should have included this in the description above) a pair of small lenses that are about 3/4 of an inch (19 mm) across and rotate one parallel to the other.

I have found when trying to fit tubes inside other tubes, metric to imperial or something else unusual, that mixing and matching works well. Try a combination of plumbing and electrical conduit. There sizes are measured in different ways, and I have used the plumbing/electrical combination a number of times to make slip joints. Also look at normal plumbing pipe combined with garden watering stuff. Combining tubing sourced from different industries provides a much wider selection of combinations/connections/fittings than sticking to just one type.

Since both lenses are the same size, I would either have to use two same sized tubes, coupled so they could turn OR use a tube the proper size and one smaller with an adpater for the lens....I will have to see when I get some funds (and time as my wife gets REAL antsy wnen I wonder around the hardware store [and she always must come along you know} (but she can take 2 hours looking for a "top" *sigh* and I am supposed to must stand there ;-)

Remember my "How long have you waited for your wife?" posting in the forums?


6 years ago

See the paper tubes I used for ¾" lenses.
And how to fix one lens on right by pressing two segments to hold
using magic tape to fit tight.
While on left a slide tube focus  with green segments holding objective lens.



Nice ! I will have to play around with this a bit to see what I, and my clumbsy hands can do :-)

Oddly, despite my being "in town" the closest hardware store of any kind is about 2-4 miles away. Businesses have not been FLOCKING to our town it appears :-) This DOES sound like the way to go however, when I am able to get away (doctor appointments before work the next two days....). Thanks

With that diameter, have you considered aluminum or plastic cigar tubes?

Hmm, That would be close to small enough in size...the tubes are to hold two lenses about 3/4 inch or 19 mm across in them "cross hairs" style, with the ability to rotate the one lens

Another option would be PVC or CPVC water pipe. In plumbing circles, pipe measurements are ID and tubing is OD. A 3/4" PVC water pipe would have an inside diameter that should fit your lens. You could place caps on the ends of 1" PVC pipe and bore through the center and insert the 3/4" pipe through the holes. The caps would serve as bushings to allow the inner pipe to rotate on an even axis. You could also mark the end of the protruding pipe and index the cap to determine the amount of rotation. Alternately, if the lenses are the same size, you could use two pieces of 3/4" pipe and a coupling in the middle. The coupling could be indexed to indicate the travel.

Yes, that would delay construction a bit until I was able to purchase the items....I was hoping to scavange something I had (the tubes I mentioned in the post are too big btw). Yes, I am using two polarizing filters in this project :-) I'd LOVE to be able to know "how far" the one lens has been turned, but I suppose markings around the one tube and one mark on the other should do the trick .

What are these reactants and products?


Sorry, if I hadn't been in such a hurry to get this posted before heading out to work, I would have doctored that diagram to eliminate those parts (since I pilfered this from the web). it was the closest thing I could find quickly to show what I meant.

Thanks, I will have to look into that; as I've been trying with materials I have handy, most of the materials I have to work with are similar to "perscription bottles" and 35 mm film canisters (the canisters are WAY too big around). I have a lot of junk, just not the "right" junk, it seems :-) They need to hold two lenses about 3/4 inch or 19 mm across in them "cross hairs" style, with the ability to rotate the one lens.


6 years ago

What CameronSS said, roll them out of paper and white glue. You could get one PVC pipe and roll the other to fit it, or roll both (potentially even using the smaller as the form for the bigger).

If they both need the strength of PVC or something sturdier than paper, try to find two sizes where the smaller fits inside the larger with a smallish gap between and build up the outside by gluing on layers of something until it's a sliding fit.

As a child I had a balloon pump- two cardboard tubes that made a sliding fit with a nozzle and one-way valve on one end, so it worked a little like a simple bicycle pump. If you can find one of these in a toy shop it could work.

Yeah, this "item" will be the size of a small "pocket" flashlight; about 3/4 of an inch (19 mm) across the lens, and the tubes able to hold them and rotate the one. Thank you for the suggestions.

I built a telescope a few years ago and used plumbing pipe from Home Depot. I found two pieces that had about 1/8" clearance then used the fuzzy stuff from stick on velcro to make a friction fit. Still working great.

My tubes will have to be able to hold a lens about 3/4 inch (19 mm) across in them and rotate the one parallel to the other.

Like CameronSS, I suggest you roll your own. I think that is the only way to have that you need. Think to use aluminum from soda cans, it is a very good material: enough workable, enough hard, free access, etc. I ised it for optics.

Paper maybe will work for you. After made the tube with some turns and vinylic glue, you can permeate it with vernice or so to give it more stiffness.

Hmmm, soda can aluminum, I will have to see if I an do something with that without cutting my fingers off....yeah, I can be doplic at times :-) Thanks

In brass, or stainless steel, try K+M metals in Chicago - or the local model shop. They sell 12" lengths of telescopic tube, in diameters up to 1"

I don't have the tools to work in brass, but paper may be an option, Thanks.