Stuck Tich piston

[duncan webster 1Participant @duncanwebster1]

I think getting a gunmetal cylinder red hot is asking for tears

[BazyleParticipant @bazyle]

Have you tried tapping it, ie small blows not making a thread. About 50 years ago in ME there was a regular section called Jeynes Corner and I think it was in there that he recounted how the millwrights in his place of work (probably in the ’20’s) when big nuts were stuck in ‘t mill they would assign an apprentice to tap it with a hammer all day and this would eventually release it. I have often found this to be sound advice if not in a hurry.

[Mark Salzedo 1Participant @marksalzedo1]

Much obliged for all the feedback. As I am in no hurry, I will experiment by positively (but not too forcibly) striking a wooden dowel about 15mm diameter with a rubber or wooden mallet to free the piston. I’m not confident that it will work but I’d rather try the least destructive options first and if unsuccessful work my way toward more damaging scenarios. On a positive note, the other piston moves without impediment and the chassis rolls freely!

[noel shelleyParticipant @noelshelley55608]

Hey Mark, we are assuming that the cause of the problem is the O ring, not metal seizure and have no idea as to the equipment you have at your disposal or your knowledge of models or engineering. The dowel will take the shock, though that is what you need so the use of wood or rubber mallet will not help, a normal hammer is fine. Place the cylinder on a solid heavy object,try to protect the machined face with thin wood or Etc the idea being to apply the load to the piston whilst supporting the cylinder.

Small press = G clamp ! Say 4 – 6″ Cut your dowel only 1/4 or1/2″ to protrude from the cylinder, keep the cut square at both ends. Remove the cylinder end cover studs if used. Place a piece of thin wood or stiff card on the fixed end  of the clamp, may be hold the clamp in a vice. Now hold the cylinder and dowel end with dowel to the screw and tighten ! This arrangement if it will still not see things your way can now be heated. Talk of “dull red” is unnecessary and way to hot ! The O ring will give up long before that temperature is reached. Some one mentioned avoiding the fumes as the O ring burns out – a good plan, best do it outside ! Good luck. Noel.

[noel shelleyParticipant @noelshelley55608]

Bazyles mention of the apprentice boy and a hammer, it works but the modern apprentice, if you can find one, not on his/her phone gets the air hammer out and in minutes has the nut off and deafens all around, that’s why the oxy propane is preferred, a skilled hand can blow the side off the nut without harming the thread if heat alone fails.

Working with salt water one knows these things ! Noel.

[Mark Salzedo 1Participant @marksalzedo1]

Really grateful for all the good advice. A little limited on tools/equipment but probably have a G clamp to fit the cylinder block and dowel. Work in garden for my wife is taking precedence over everything at the moment but hope to work on cylinder/piston in the next week or so!

[Mark Salzedo 1Participant @marksalzedo1]

Good news. Just pushing a 16mm wooden dowel into the bore and pushing hard released the piston. It now slides freely in the cylinder. A big thank you to all of you who kindly took the time to share your suggestions. Now to put it all back together again!

[Mark Salzedo 1Participant @marksalzedo1]

I’ll post a video, if and when, I manage to get it running on air.

[Michael GilliganParticipant @michaelgilligan61133]

Well done, Mark

I’m sure we are all keen to see it run.

MichaelG.

[Mark Salzedo 1Participant @marksalzedo1]

Thanks Michael.

[noel shelleyParticipant @noelshelley55608]

Nothing better than a good outcome Mark. Good Luck. Noel.

[Mark Salzedo 1Participant @marksalzedo1]

Thanks Noel.

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