# My experience Fitting a Gauge to Gaggia Classic - plus a Good site for parts



## DINC (Feb 11, 2015)

So the drill bit finally arrived yesterday and finally got to fit my gauge. I just wanted to add some pictures of the fittings I found and used as they were incredibly cheap and easy (for any newbies like myself) to install!

I couldn't quite put my faith in the plastic push connectors as they where only rated to 10bar so I went looking for something a bit more sturdy!

Unfortunately the gauge is 51mm in diameter so doesn't go flush to the case . . . YET! I've ordered a sanding cone drill bit to resolve that later in the week.

Anyway, for anyone who has one and wants to adjust the OPV valve or install a gauge, here is a list a things I used and some pictures:

O/D = Outer Diameter

I/D = Inner Diameter

Hole Saw Tooth Drill Bit - 50mm

http://www.ebay.co.uk/itm/251689894242?var=550596200452

4mm I/D - 6mm O/D Tube

http://www.ebay.co.uk/itm/261408670856?var=560302314319

1/8" BSPP Female Thread Stud - 6mm O/D - 4mm I/D

http://www.airlinkcompressors.co.uk/products/stud-quick-brass-fittings

Pressure Gauge 1/8" BSPP - Back Connection - 14 Bar

http://www.airlinkcompressors.co.uk/products/pressure-gauge-1-8-bspt-x-50mm-dial-centre-back-connection-0-to-300-psi

Equal Tee Fitting - 4mm I/d - 6mm O/D

http://www.airlinkcompressors.co.uk/products/equal-tee-quick-brass-fittings









Cheers, Jake


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## froggystyle (Oct 30, 2013)

Liking that!


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## gingerneil (Aug 21, 2014)

Looks excellent! Was the case easy enough to drill ? Such a shame that the gauge isn't 50mm! Not the end of the world to fix.. but a pain!


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## mremanxx (Dec 30, 2014)

Not critising but why is the gauge at the size and not the front where it can be seen?


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## DINC (Feb 11, 2015)

gingerneil said:


> Looks excellent! Was the case easy enough to drill ?


Yeah just took it slow with even pressure and it goes! Used some oil after the initial cut otherwise the bit would have become blunt very quickly



mremanxx said:


> Not critising but why is the gauge at the size and not the front where it can be seen?


Simply, I have a year 2000 model gaggia with the badge on the front like this one:









and I just didn't really want to ruin it! Plus its sat on the right hand side of a breakfast bar so I can peek at the gauge when needed to check all is well!

It wont be a good mounting place for all, but you could certainly get a smaller gauge and do the same thing on the front!


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## MrShades (Jul 29, 2009)

How is the stability of the needle with all of that large bore tubing running directly to it??? I thought that, usually, capillary tubing was used on pressure gauges (and long lengths of it) to dampen the needle and ensure it was stable.


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## mremanxx (Dec 30, 2014)

DINC said:


> Yeah just took it slow with even pressure and it goes! Used some oil after the initial cut otherwise the bit would have become blunt very quickly
> 
> Simply, I have a year 2000 model gaggia with the badge on the front like this one:
> 
> ...


*Makes sense now*, BTW have you noticed that the Ebay site states that the tubing you bought should not be used in food prep over 25 degrees.

It doesn't look as thick as the original stuff, just in case it ruptures and floods you machine.

have you had any issues with the screw nuts leaking?


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## mremanxx (Dec 30, 2014)

MrShades said:


> How is the stability of the needle with all of that large bore tubing running directly to it??? I thought that, usually, capillary tubing was used on pressure gauges (and long lengths of it) to dampen the needle and ensure it was stable.


Doesn't make any difference on mine Boots, I have the capillary tube one but it still vibrates, wish I had bought a glycerine fill gauge now.

Still you live and learn


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## MrShades (Jul 29, 2009)

I've got a non-glycerine but with capillary tube and it's rock solid....

...and I'm the other "Mr"... Shades, not Boots... ;-)


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## MrShades (Jul 29, 2009)

mremanxx said:


> *Makes sense now*, BTW have you noticed that the Ebay site states that the tubing you bought should not be used in food prep over 25 degrees.
> 
> It doesn't look as thick as the original stuff, just in case it ruptures and floods you machine.
> 
> have you had any issues with the screw nuts leaking?


It's cold water essentially anyway - so 25 degrees isn't an issue.


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## mremanxx (Dec 30, 2014)

MrShades said:


> I've got a non-glycerine but with capillary tube and it's rock solid....
> 
> ...and I'm the other "Mr"... Shades, not Boots... ;-)


Sorry mate, wonder why mine vibrates?


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## MartinB (May 8, 2011)

My gauge vibrates like mad too. It rarely stays static!


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## El carajillo (Mar 16, 2013)

You can get a certain amount of vibration from the pump (vibratory pump = small pulses).

If there is strong vibration it could be you have a small air bubble trapped some where , which will compress and exaggerate the vibration.

If the tubing wall is too soft ? this would help vibration as well.


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## mremanxx (Dec 30, 2014)

MrShades said:


> It's cold water essentially anyway - so 25 degrees isn't an issue.


Yeh what a twat I am, the bloody hose is before the boiler. You can be my care in the community officer Shades


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## mremanxx (Dec 30, 2014)

El carajillo said:


> You can get a certain amount of vibration from the pump (vibratory pump = small pulses).
> 
> If there is strong vibration it could be you have a small air bubble trapped some where , which will compress and exaggerate the vibration.
> 
> If the tubing wall is too soft ? this would help vibration as well.


Might be air bubble, will try bleeding, will not be the plastic pipe as I am using commercial vehicle air brake tubing so it is thick walled.


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## Kai (Feb 1, 2015)

I should be attempting this later on in the week , as regards to the pressure on the gauge , what pressure am I looking to set it as ?

I know you are looking at 9 bar at the group head but I'm sure I've read somewhere that it needs to be 10 ( something to do with static vs dynamic pressure )


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## mremanxx (Dec 30, 2014)

Kai said:


> I should be attempting this later on in the week , as regards to the pressure on the gauge , what pressure am I looking to set it as ?
> 
> I know you are looking at 9 bar at the group head but I'm sure I've read somewhere that it needs to be 10 ( something to do with static vs dynamic pressure )


That's about right, 10bar when brewing is good.


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## Kyle548 (Jan 24, 2013)

Might be interesting to try a pressure profiling mod.

Easiest way is probably a potentiometer at the pump so you can do PI and ramp or decrease pressure as you like.


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## Kai (Feb 1, 2015)

mremanxx said:


> That's about right, 10bar when brewing is good.


Ok gauge fitted , proper nylon ( not pvc ) pipe installed 

Now after flicking the switch and laughing at the needle going berserk there is no way that I can read the pressure , BUT when I flick the switch off the needle settles and the pressure is indicated. I presume this is fine.

Btw it's now adjusted to 10 bar


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## El carajillo (Mar 16, 2013)

Can you bleed the air out of the pipe to the gauge ? If it is filled with air this will cause fluctuation


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## Kai (Feb 1, 2015)

The airs all bled out , I think it's more of an action of the pump causing the vibration .

Longer term I will get a oil filled gauge to dampen the needle


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## GranGaggia_old_version (10 mo ago)

mremanxx said:


> Doesn't make any difference on mine Boots, I have the capillary tube one but it still vibrates, wish I had bought a glycerine fill gauge now.
> 
> Still you live and learn


 I made a post about making a snubber from a small peace of aluminium/copper. Its a mettle disk with a tiny prick in the center, it sandwiches between the pressure guage and the pipe connection, a snug fit will reduce your wobble by effect of slowing down the rate at which the pressure and change at a given line pressure. 
'pressure guage Snubber' is the main idea.


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## Bhodgson (11 mo ago)

GranGaggia_old_version said:


> I made a post about making a snubber from a small peace of aluminium/copper. Its a mettle disk with a tiny prick in the center, it sandwiches between the pressure guage and the pipe connection, a snug fit will reduce your wobble by effect of slowing down the rate at which the pressure and change at a given line pressure.
> 'pressure guage Snubber' is the main idea.


Far simpler just to increase the length of the copper pipe. And coil it up for space saving.


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