Stuck Friction Fit?

[architect]

I have this task chair where the cylinder is friction fitted to the wheelbase. Removal should just require hammering the cylinder out from the underside as shown here:

But I have struck many times without success. I've struck so hard that the casters flew off but not the stem. Thoughts? WD-40? Heat? I'm trying not to ruin the paint job.

 

[DavidR8]

I would carefully try a heat gun. The base is likely cast aluminum and the cylinder is steel so the base will expand more and should free it up.

 

[YotaBota]

I did one a while ago that was a real pita. I had to take the back off, turn the chair upside down supporting the base keeping the seat off the floor and then got out the 4lb micro adjuster. It took a few more good whacks but in the end I won the battle.

 

[architect]

I'm not home so tried with a pretty hot hair dryer and still no go! I even tried to do the other end first with some heat and will not release on either end! Am I just not hitting it hard enough or what!

EDIT: I got the base off! The difference was striking the chair like I hated its guts (and a lot more heat).

 

[Tecnico]

First question, what are you trying to achieve? Do you want to replace a bad cylinder or change out the sleeve it fits into or the base to change the height of the chair or repurpose some of the pieces for something else? E.g. if it’s just the cylinder then the sleeve can stay where it is, see below about releasing the cylinder.

OK, if the sleeve has to come out, first of all take the ram cylinder out of the tube that fits into the chair base, that little circlip on the bottom releases it. A hand full of bits will come with it including a thrust bearing and spacers.

Then, find/make a jig that the tube will slip into and support the assembly inverted by the chair base. I’ve used a 5 gallon bucket but you need something more robust and that will protect the chair base. Your jig wants to be something rigid like a hunk of pipe sitting on a concrete floor so when you hit it the force isn’t absorbed by the support jig.

I typically start with a 3 lb ball pien but when I get a stubborn one I get out the 8 lb sledge. With the chair base firmly supported, a good firm blow should release the sleeve. The 8 lb is good because it leverages lb-ft vs ft/sec., you can get a good thump of energy without a big swing.

Protect the end of the sleeve with a piece of hardwood and put something below the sleeve to cushion it when it pops free……I know this, LOL!

There is a 2-1/2 degree included angle on the base/tube interface.

Good luck!

D

 

[architect]

I was swapping to a different length cylinder. It took back and forth heat with a hair dryer and hitting with various hammers. I am absolutely exhausted

 

[Tecnico]

I was swapping to a different length cylinder. It took back and forth heat with a hair dryer and hitting with various hammers. I am absolutely exhausted

FYI, you can get sleeves that have the tapered "fit" position (in the rolling chair base) at different heights, you may only need to swap out the sleeve not the whole sleeve/cylinder package. I've used that tactic to get a higher sitting position to fit my somewhat longer frame.

D

 

[neer724]

I have removed these cylinders in the past - what I did was take a socket that just fits the size of the OD of cylinder and then using a 5lbs hammer I give it 1 or 2 good blows and it goes flying out...

 

[6.5 Fan]

Years ago an old blacksmith told me, " if your going to hit something, hit it hard, No tapping."