Piston Help
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LiveSuperMatt
- Posts: 1
- Joined: Mon Mar 04, 2013 8:39 am
Piston Help
Is there any way to get a power piston to work in a glass tube if the ID of the glass is out of round by 0.003? I can't find glass tubing with precise ID's.
Re: Piston Help
Maybe. here is what master stirling builder Jan Ridders says about glass tube:
"The tolerance of the inner diameter of the tube in what the working piston is running must be fairly small: +/- 0.03mm or smaller; most common test tubes don’t fulfill this requirement. You can find suppliers for this kind of good quality glass tubes on internet also (try “Schott Fiolax” or “Duran”),""
.03mm = .001" So plus or minus .03mm = total variation of .002"
Bengs Modelbrau sells suitable tube at at http://www.bengs-modellbau.com/material ... ttubes.php
They say their tube is plus or minus .05mm, which equals .002" almost. So total variation of .004", which seems like a hell of a lot when on a metal cylinder the fit is always made to be less than .001" clearance.
"The tolerance of the inner diameter of the tube in what the working piston is running must be fairly small: +/- 0.03mm or smaller; most common test tubes don’t fulfill this requirement. You can find suppliers for this kind of good quality glass tubes on internet also (try “Schott Fiolax” or “Duran”),""
.03mm = .001" So plus or minus .03mm = total variation of .002"
Bengs Modelbrau sells suitable tube at at http://www.bengs-modellbau.com/material ... ttubes.php
They say their tube is plus or minus .05mm, which equals .002" almost. So total variation of .004", which seems like a hell of a lot when on a metal cylinder the fit is always made to be less than .001" clearance.
Re: Piston Help
The other way round the problem might be to use a leather cup seal on a slightly loose piston, this will comform to any slight out of round. Ian S C