What tool?

[babylou]

I need to tightly grip the inside of a plastic cylinder with some sort of tool then be able to pull very hard and twist left. Size range is 2.25 in to 4 in. Any off the shelf ideas? I know how to design & build a solution but am too busy.

 

[2oolhound]

I'm thinking of exhaust pipe expanders then grip the end with a pipe wrench or something. Trouble is it may chew up the inside.

How about a soft rubber plug with a slot through the centre, say 1/2" wide and 1" long. Insert a steel bar 3/4" by 3/8 so it spreads the slot when you turn it causing the rubber to widen and grip the inside of the tube.

 

[gearhead1]

Yes. Get a sway bar bushing set from the auto parts store. Put a rubber bushing on each end of the cylinder with a bolt or threaded rod in the center. Tighten a nut at each end so the rubber deforms out and grabs the cylinder.

I made a fixture similar to this before to spin piston wrist pins without damaging or marring them.

 

[gearhead1]

Something like this.

 

[chrisexv6]

Either the exhaust expander, which can be used as mandrels also, wrapped in rubber sheet it will not leave a mark.
Or
Try a pressure test plug for plumbing. Firm rubber inside grip rim, can be tightened to the moon, good grip, $4 to $7. Withstands lots of pressure and will withstand lots of torque twist.
Youve seen them. Three pieces and a wing nut in the middle. Round... Usually red or black. They're in the plumbing aisle of box stores.

Yeah, something like this: http://www.homedepot.com/p/Sioux-Ch...de-Fit-Mechanical-Test-Plug-HD882-4/202313214

But its plastic so I dont know how hard you can pull and turn on it.

I have used one as an adapter for my pool plumbing to go from air line to the actual PVC plumbing to blow it out with an air compressor. Worked great!

 

[babylou]

I need to pull and twist left after attachment. Can't do that with a rubber plug or exhaust expander.

 

[larry_g]

Do a search for 'internal pipe wrench' They make such a tool in a variety of configurations.

lg
no neat sig line

 

[Rookie2]

http://www.amazon.com/s/ref=bl_sr_hi?ie=UTF8&field-brandtextbin=G.T.+Water+Products&node=228013

maybe with air pressure rather than water .

 

[gearhead1]

I had assumed it was accessible from only one side.
Where do you get sway bar bushings that are four inches around?

Sway bar bushings, not so much on the high side, but the concept remains. Rubber bushings can be found 4" no problem, check this out.

http://www.ebay.com/itm/NEW-LORD-J5...277?pt=LH_DefaultDomain_0&hash=item4635c4717d

Another idea would be to get rubber cones with a through hole, that way one set would work with the entire range of ID. Or rubber cone similar to the engine block chamfer, one on each end maybe.

http://www.ebay.com/itm/Whitney-MFG...1661263822&pt=Motors_Automotive_Tools&vxp=mtr

 

[gearhead1]

Pull and twist....ok. Can you go through the center of the part?