Brass machinist? Espresso Machine modification

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seoras

101 posts

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#282621 2-Mar-2021 09:02

I picked up a nice Espresso Machine on TradeMe last spring which hadn't been looked after (never been cleaned!).

Even after a solid renovation it wasn't making good coffee and after much research and discussions on the coffee websites forums I came up with a solution which was to reduce the heat exchangers restrictor value from 3mm to 2.5mm.

I pulled this off by inserting copper wire with a diameter wide enough to reduce the 3mm hole area to the equivalent that a 2.5mm would have.

It's a hack but the coffee is now outstanding!

I'd like to find a machinist who can take the restrictor value (I've ordered a spare) and copy it accurately but put a 2.5mm hole in it.

Perhaps even make a few of them (depending on cost) so I can try a range of sizes.

I'm in Cambridge so preferably someone in the Waikato. Could post it though, it is tiny.

Thanks,

George

RunningMan

8965 posts

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#2666611 2-Mar-2021 09:06

A music tech that does brass & woodwind would be able to do this.

bmoff

158 posts

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#2666618 2-Mar-2021 09:26

PM'd you.

afe66

3181 posts

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#2666630 2-Mar-2021 09:52

Maybe a photo of what your after.

Is it threaded?

I have got a lathe, brass and drills for those sizes but i see someone else has PMd you already.

A.

Are there any lead implications though? Some brass alloys have lead in them. Would aluminium work?

seoras

101 posts

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#2666641 2-Mar-2021 10:09

afe66: Maybe a photo of what your after.

Is it threaded?

I have got a lathe, brass and drills for those sizes but i see someone else has PMd you already.

A.

Nope not threaded. It's 14mm at one end and 9mm at the other.

Bmoff is local and I've sent him an email with these photos. I should have just posted them here in the first place!

afe66

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#2666649 2-Mar-2021 10:35

Looks like brass and copper components. Or maybe the brass is aluminium copper alloy ?nordic gold

I expect you will have to get the taper right for a tight fit ?

Local would be better as can test fit the part while in workshop.

seoras

101 posts

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#2666660 2-Mar-2021 10:54

afe66: Looks like brass and copper components. Or maybe the brass is aluminium copper alloy ?nordic gold

I expect you will have to get the taper right for a tight fit ?

Local would be better as can test fit the part while in workshop.

No it's a single piece, brass I think although you could be right about an alloy. The colour differences are just staining and oxidisation.

Yes, the taper needs to be perfect for the joint to get a good seal.

Fred99

13684 posts

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#2666907 2-Mar-2021 18:16

So is this to reduce flow through the thermosyphon so that the boiler temp / pressure can be increased for better milk steaming without overheating the group? (ie reduce the amount of flushing needed to stabilise the group temp?).

(I'm assuming the custom giglar you want is on the HX - not the brewing circuit where the flow reducers are much smaller)

I've played around with my now 9 year old Rocket HX machine, OTOH the tray on the rocket is plumbed to waste so I don't need to empty it, so pre-flushing is easy/no fuss. Most of the things I used to worry about, I don't any more. Making a coffee with an E61 machine eventually becomes an "automatic process" you can do without really thinking.

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seoras

101 posts

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#2666928 2-Mar-2021 19:14

Fred99:

So is this to reduce flow through the thermosyphon so that the boiler temp / pressure can be increased for better milk steaming without overheating the group? (ie reduce the amount of flushing needed to stabilise the group temp?).

(I'm assuming the custom giglar you want is on the HX - not the brewing circuit where the flow reducers are much smaller)

I've played around with my now 9 year old Rocket HX machine, OTOH the tray on the rocket is plumbed to waste so I don't need to empty it, so pre-flushing is easy/no fuss. Most of the things I used to worry about, I don't any more. Making a coffee with an E61 machine eventually becomes an "automatic process" you can do without really thinking.

Yes. The restrictor (gigleur) is located at the top of the thermosyphon outlet.

I was having to pre-flush almost a cup full of water to get the temperature down to a level that didn't taste burnt.

I've got an "Eric's thermometer" installed on the E61 head so I can estimate what the actual temperature is hitting the puck during the shot.

A mate of mine bought an old Rocket E61 base model. Must be ~15 years old at least and his machine pulls a perfect shot every time without flushing.

I think that is why Rocket's are so popular because they've gone the extra distance with the thermosyphon tech where other manufacturers haven't.

I used to think it was because Rocket is owned by a Kiwi that they were popular (might be in part!) but they really do have a good rep on the home barista forums and my mate's is a beauty even at its age.

I suspect my machine used too wide an outlet in the restrictor to give it a quicker warm up time. It's rebound time hasn't changed noticably but the warm up time has gone from 15-20mins to 25-30mins. I can live with that as long as the coffee is good and, yeah, what a difference making the hole 0.5mm smaller!

As you say, I can now just pull a good shot without having to fret over what the thermometer on the head is saying as I trust it now. It's an "automatic process".