Shim options- whats out there?

[tarbellb]

Hey there, so you may remember my post about tap & die issues on a tube clamping project - http://www.garagejournal.com/forum/showthread.php?t=339269

Well I have all the pieces now and the clamp is not pinching enough to properly lock the telescoping tube inside.

What I am looking for is options on how to get better clamping action.


Here are the specs:

1" OD x .065" inside tube

telescoping inside of

1.25" OD x .090" (=1.07" ID) outside tube

Leaving about .07" GAP.

Clamps seems to be pulling about .03 - .04"? Leaving the inside tube to move freely.

Considerations for the problem:

_ needs to move freely when not engaged

_ will not be subject to many cycles (maybe 100's?)

_ needs to be permanently installed, ie cant loose it

So I am thinking a shim, would prefer a shim with a flange for better stability.

The closest thing I could find is -
http://www.mcmaster.com/#1281n28/=14d785x

Also thinking about a adhesive backed shim strip to run on the ID of the outer tube?

 

[LXCam]

They make shaft sleeves in all kinds of sizes.

http://www.skf.com/us/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html

 

[az45]

Do you already have the tube? Tube from different mills will be different sizes. I'm working on something similar right now for seat sliders. I like what you're doing, I may change the way I was going to do it.

 

[tarbellb]

Thanks guys.

LX, excellent suggestion. This is why I post here, lots of info and solutions I have never heard of.

After researching the shaft sleeves, which is almost exactly what I was imagining I also found the price.... $50+ depending on seller.

Seems anything that has this kind of tolerances is going to be expensive, understandable.

So I have decided to go with tighter tolerance tube. Plan on using some DOM (no inner weld to worry about) and HREW and see if I cant get my play < .05" then my clamp will perform.

 

[ilovevocs]

Could you slot the other side of the tube you currently have and design the clamp with two screws?


Sent from my iPhone using Tapatalk

 

[Marctrees]

Could you slot the other side of the tube you currently have and design the clamp with two screws?



That ^, or at least, add the second slot and try w the clamp you already have for a quick easy test.

Or ?? maybe even ?? 3 slots at 120 deg apart ??

Side note - I tnink most bycicle seat post clamps have one slot, but probably a snugger fit to start with. Marc

 

[oldironfarmer]

Can you not make your slot wider so the screw can pull it down farther?

 

[Marctrees]

Just another idea- Blast w a sharp angular material like "Black beauty" or something, on the portion of your insert pipe that goes in the clamping area.

That "tooth" could make a huge difference.

Although, it's bite could decrease after many actuations (sliding)

Just brainstorming. Marc

 

[tarbellb]

Ive played with the idea of making the slot wider, or additional slots but there is just to much play. It would start getting pretty sloppy looking, and maybe not perform.

I ordered 2" OD DOM w/ a 1.76" ID to slide over 1.75" OD HREW tube. We will see if it works.

Also, I switched up my clamp. I like the bike seat tube clamp but need something a bit more robust, going to try "truss clamps". Used for truss structure to hang lights and such.

 

[red92s]

Also, I switched up my clamp. I like the bike seat tube clamp but need something a bit more robust, going to try "truss clamps". Used for truss structure to hang lights and such.

Here you go:
http://shaft-collars-couplings.staf...llars/staff-lok--collars-hinge-type/slc2l200h

 

[Marctrees]

And , another page at Red92s site -

http://shaft-collars-couplings.staf...round-bore-shaft-collars/stafford_quick_clamp

Marc

 

[EdT]

.070 is a lot to take up with the clamping arrangement you have. More slots might help. make sure the clamp is not bottoming out before you're tight. Likewise, be sure the slot is not closing before you're tight.

 

[red92s]

.070 is a lot to take up with the clamping arrangement you have. More slots might help. make sure the clamp is not bottoming out before you're tight. Likewise, be sure the slot is not closing before you're tight.

Sounds like his new material selections will cut that to ~.010" which is a pretty nice fit.

 

[tarbellb]

Here you go:
http://shaft-collars-couplings.staf...llars/staff-lok--collars-hinge-type/slc2l200h

Came across these a few years ago, totally rad but very expensive.

I need to keep the cost down, maybe $10 total for the clamping method. But also keep the quality and aesthetics pretty clean.

Appreciate all the help!