coupling cardboard to a shaft

[Gorpomon]

Hi, I have a shaft that has a cardboard tube slide over it. I want the tube coupled to the shaft so they spin together. The problem is that cardboard tube is completely covered on top, so I can't just put a clamp on an exposed section and be done with it.

Basically the cardboard needs to be coupled to the shaft internally.

Currently the shat it slides on is 2-7/8" OD and the cardboard tube is 3" OD.

Does anyone know of anything that I can get that can take up clearance, like a set of shims for a shaft or the like?

 

[MikeHalloran]

Duct tape.


Mike Halloran
Pembroke Pines, FL, USA

 

[mcgyvr]

super glue

 

[SnTMan]

Carpet tape, caulk, chewing gum...

 

[MikeHalloran]

Gorilla Glue will fill a gap nicely, if you can wait for it to harden.


Mike Halloran
Pembroke Pines, FL, USA

 

[KENAT]

What's the ID of the tube?

Is this some kind of rough proto, or something you'll deliver to customers or what?

Look at how they do it on plotters and the like if for production.

If for proto or similar then as Mike suggests, I'd probably wrap some kind of tape around the shaft at either end until I got enough for a slight interference, maybe reinforce it with a little adhesive.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[Gorpomon]

Thanks for your answers everyone. One thing, these tubes are frequently pulled on and off the shaft, so glues are probably out of the question. It won't be delivered to customers except in rare instances.

However, the shaft has no problem if duct tape is on its end. So before the material rolls onto the shaft, I'll duct tape the cardboard to the shaft.

I'll experiment with combinations of grip tape and duct tape to get my desired results. However please advise if you think there's a better way.

 

[btrueblood]

Slide an o-ring over the shaft, and the tube over the o-ring?

 

[flash3780]

Slide an o-ring over the shaft, and the tube over the o-ring?

A couple of o-rings sounds like a good way to do it. You could cut some o-ring grooves in the shaft to hold them in place and slide the cardboard over it. You might have to experiment a bit to figure out the proper amount of interference, though.

What's the function of the cardboard?

 

[TheBlacksmith]

I like the o-rings, or a couple of those wide rubber bands the Post Office puts around presorted bundles of mail. I get the rubber bands from my mail carrier when I ask for them; I suspect they are considered disposable and a cost of doing business. They work great for my weekly pill carrier when I'm packing for trips and know my baggage will be gently handled by everyone until I finally see it again.

 

[MadMango]

Tolerance rings is another approach.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[1gibson]

Grip tape is a good idea, semi-permanent mount to the shaft, slight interference fit should prevent cardboard from spinning, with minimal damage (scuffing.)

Not sure what the product is though... Is shaft a constant fixture, or the end product? Is carboard tube a replaceable test fixture, or the end product?

I'm imagining a shaft with traditional keyways cut into it (2 @180* or 4 @ 90*.) Instead of traditional key, the 'key' is a piece of spring steel that is longer than the keyway. Set screw the ends down into the shaft so the middle curves up above the shaft OD.

This will provide some tension on the tube as it slides on (vary the tension by the length or thickness of the spring steel) without damaging the surface or making installation/removal difficult.

 

[asimpson]

food for thought

http://www.google.ie/search?hl=en&b...=1&q=expanding+shaft+chuck&aq=o&aqi=&aql=&oq=

 

[Compositepro]

asimpson nailed it. 3" cardboad cores are a standard size in many industries and there are hundreds of commercial products that can meet your needs. Check out Converting Magazine and Paper, Film, and Foil Converter Magazine (

http://pffc-online.com/).

They also have buying guides.

 

[chicopee]

You could cut serrations on the end of the cardboard tube and use a clamp on the serrated end.

 

[flash3780]

You could cut serrations on the end of the cardboard tube and use a clamp on the serrated end.

To that end, you could simply clamp the cardboard tube onto the shaft with a hose clamp.

 

[Compositepro]

It helps to completely read the original question:

"The problem is that cardboard tube is completely covered on top, so I can't just put a clamp on an exposed section and be done with it."

 

[flash3780]

It helps to completely read the original question:

Ha, the funny thing is that I read that earlier but then forgot.

 

[unclesyd]

Compositepro, has it right as to what you need. You need what is called a bobbing holder, in some processes, that will allow you to remove and grip the paper tube. There are many types out there using different mechanisms to hold and release the tube. We mainly used two types for hold thin tubes, one was the air bladder type and the other was an internal expanding mandrel mandrel. The air bladder type was use on very thin tubes while the mandrel type was used on the heavier wall tubes.
The bladder type would also allow more clearance while the mandrel type would normally require almost a slip fit. This was because you wanted very little expansion in the mandrel to insure that the tube stayed round.
Sorry I don't have any links as all the manufacturers and suppliers that I was acquainted with are no longer in business since the demise of the textile industry.