Rubber piston dimensions??

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Rubber piston dimensions??

Post by mconsidine »

I've searched the forum and google and come up empty handed on this. What I'm trying to find the dimensions of the rubber piston inside the Lunt pressure tuners? I'm trying to figure out how doable it is to make a manual adjustment of pressure (using the automotive "pistol grip" unit mentioned elsewhere) with readily available parts. Any thoughts, pointers, experience with this mod would be appreciated. I don't need computer control, but I suspect my hands/knuckles over time will thank me.

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Gordon Ewen
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Re: Rubber piston dimensions??

Post by Gordon Ewen »

Hello Matt, I thought you might be interested in how I control the pressure in my tuners. You may have a solution by now but here's what I have:
Adjusting the pressure tuners manually is a pain and Lunt sell a microprocessor controlled box for £1100!. An engineer friend of mine decided to make a pressure adjustment system much more cheaply. It consists of an airbrush compressor, a pressure regulator valve, and a rubber bung with a hole drilled in it to replace the piston in the tuner. Total cost was about £100, see the attached pictures. Note I have a double stacked system so there is a splitter in the air supply line so that 2 regulator valves can be used. I have a write up of the assembly somewheere, if you are interested I'll try and di it out.
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Re: Rubber piston dimensions??

Post by rsfoto »


Very neat solution as those pressure walves keeps the presuure constant all the time. The question is only how easy they to make fine adjustments but I saw the scale from 0 to 1 psi is quite wide.

Very well done. I would recommend to fix the tube to the pier with a loop long enough so you can move to all sides with the telescope. This ahs the advantage that you always have the same weight of tubing acting on the mount.

regards Rainer

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