Longitudinally locked rotating cylinders

AI Thread Summary
The discussion focuses on creating two close-fitting, longitudinally locked cylinders that can rotate against each other with minimal parts. The proposed solution involves machining grooves in the cylinders and using a Teflon ring for smooth rotation. Concerns are raised about the security of this arrangement and the suitability of Teflon as a material. The dimensions of the cylinders are specified, along with the need for resistance to accidental rotation while allowing easy manual operation. Additional suggestions include using vinyl tubing for ergonomic benefits, but clarity on the design's purpose is sought.
KuKu427
Messages
10
Reaction score
0
I need to make two close fitting cylinders that are longitudinally locked in position but need to rotate against each other. I want to make this in as few parts as possible.

I was thinking of machining grooves in each cylinder and placing the Teflon ring in the groove of the inner cylinder and pressing the outer cylinder on.

How secure would this arrangement be?
Are there any other alternatives?
Is Teflon the ideal material for the ring?

Thanks in advance for any help.
 
Engineering news on Phys.org
I would need more information on the overall limits or constraints, i.e. speeds, forces, etc... to begin to answer your question.
 
FredGarvin said:
I would need more information on the overall limits or constraints, i.e. speeds, forces, etc... to begin to answer your question.

The tubes are fairly small.
11.2mm ID, 12mm OD for the inner.
12.05mm ID, 13mm OD for the outer.
approximately 40mm in length for the inner, 10mm for the outer.

Force is what a person will apply to rotate the tubes with his fingers The person should be able to turn this easily, but not so easily that everyday bumps and nudges will turn it on (it's a rotating sleeve used to activate a reed switch). Longitudinal slop or play is a definite no-no.

It has to be able to resist sufficient force that the outer tube will not strip off unless someone puts some effort into it.
 
Sounds like your aim is to either insulate the user ("Teflon rings") or provide some ergonomic benefit by increasing the OD of the control...

In either case, how about using a 10mm length of vinyl tubing over the 10mm OD control?
 
tyroman said:
Sounds like your aim is to either insulate the user ("Teflon rings") or provide some ergonomic benefit by increasing the OD of the control...

In either case, how about using a 10mm length of vinyl tubing over the 10mm OD control?

No that's not what I am doing.
 
What are you doing? Do you have a simple sketch? What is the endgame for this device?

Thanks
Matt
 
Posted June 2024 - 15 years after starting this class. I have learned a whole lot. To get to the short course on making your stock car, late model, hobby stock E-mod handle, look at the index below. Read all posts on Roll Center, Jacking effect and Why does car drive straight to the wall when I gas it? Also read You really have two race cars. This will cover 90% of problems you have. Simply put, the car pushes going in and is loose coming out. You do not have enuff downforce on the right...
I'm trying to decide what size and type of galvanized steel I need for 2 cantilever extensions. The cantilever is 5 ft. The space between the two cantilever arms is a 17 ft Gap the center 7 ft of the 17 ft Gap we'll need to Bear approximately 17,000 lb spread evenly from the front of the cantilever to the back of the cantilever over 5 ft. I will put support beams across these cantilever arms to support the load evenly
Thread 'What's the most likely cause for this carbon seal crack?'
We have a molded carbon graphite seal that is used in an inline axial piston, variable displacement hydraulic pump. One of our customers reported that, when using the “A” parts in the past, they only needed to replace them due to normal wear. However, after switching to our parts, the replacement cycle seems to be much shorter due to “broken” or “cracked” failures. This issue was identified after hydraulic fluid leakage was observed. According to their records, the same problem has occurred...
Back
Top