fr3dopyrox Posted April 27, 2018 Posted April 27, 2018 I pressed a rocket with an homemade tube support and bottle jack 4tons,but i haven't gauge!, When I removed the tube of the support, he was a little damaged, in your opinion I pressed too hardly? the tube is a little damaged and it's only a 4tons bottle jack press; how it possible? thanks a lot....
Baldor Posted April 27, 2018 Posted April 27, 2018 (edited) An image of the tube and of the support will help. I'm damaging a lot of tubes, bending spindles, etc... Learning to make and use my own tooling. First suspect: Too much presure. Second suspect: Too big increments. Third suspect: Bad tube or support. Edited April 27, 2018 by Baldor
Mumbles Posted April 28, 2018 Posted April 28, 2018 Everything Baldor said could be the case. Also consider what size rockets you're making. Even a 1" ID rocket would be getting over 10,000 psi with that jack, which is too much for many tubes to handle.
Baldor Posted April 28, 2018 Posted April 28, 2018 If you are going to press with a bottle jack, you need one of two things, preferably both: A force gauge: http://www.skylighter.com/fireworks/arbor-press-force-gauge.asp Install a manometer in the jack: http://www.albroswift.com/jack.htm There is no way you can know what pressure you are applying without those. Both you can make yourself or bought finished. I missanotated the reading on the manometer when calibrating for 3/4" tubes. I wanted to apply 6500PSI, I finished applying 15000PSI without a sweat with a 6T press. I not only bursted the tube, but also bursted the tube support. I didn't feel I was overpressing until I saw the support open. I also made some tests with bentonite and a 20mm diameter, 1mm wall thickness steel tube. You can make the tube swell a few mm without a sweat. What I'm saying is... You can apply an enormous force with a bottle jack, and you can't feel it. You need instruments to measure it.
Arthur Posted April 28, 2018 Posted April 28, 2018 I once saw the press tool to make 3" gerbes. The tube support bit was basically a 6" diameter piece of hardened tool steel with a bore for the card tube. Sometimes the sleeve needs to be strong, Maybe stronger than split pipe and hose clips.
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