Thread: Putting a M10 female on a 8 mm tube

Silver soldering SS works beautifully! That would be my choice unless you may want to change over nozzles.

The brake nut does not look like stainless to me - it looks like passivated steel so it will eventually rust.

The threaded adapter method is the best one of the 3 you propose.

I would be making an adapter with some SS rod - know anyone with a Metal work lathe?

But first...what are you hoping to achieve? Better aeration?

Greg

A bush with M10x1 OD and M8 ID is getting pretty thin. I'd be looking at making an extension piece so that you can get a decent wall thickness. As Bob says, you would be better with S/S, if only for food contact reasons (who wants rusty milk?).
Worth noting that M10x1 is not a standard thread (except in Japan). The die is likely to be a special order. You would be far better finding someone to make this for you - tapping S/S can have some tricks too.

But as Greg (the man who sets the bar for baristas) asks, why?

Michael

I did something similar on a steam wand. My wand is chrome plated brass not stainless. I bought a replacement nozzle and a threaded adapter from a coffee parts place and silver soldered it on. Still going strong.

I would however say that those kind of coffee pots may struggle to drive enough steam for bigger and more holed nozzles.

I think quality of milk foam is more about technique. Milk must start cold and use a suitable size jug. Never re-froth milk. Plenty of videos on utube etc. practice makes perfect. 3 kids and a wife demanding hot chocolate drinks gives plenty of opportunity to perfect my skill.

James



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Originally Posted by BobL

The brake nut does not look like stainless to me - it looks like passivated steel so it will eventually rust.

The threaded adapter method is the best one of the 3 you propose.

I would be making an adapter with some SS rod - know anyone with a Metal work lathe?

Ah yeah, I forgot about that, the nut won't be stainless. Thanks, that saved me an ebay order. Unfortunately I don't know anyone with lathe--maybe I might check out the Men's sheds in the area as I wouldn't mind learning the art a bit either.

Originally Posted by Greg Q

But first...what are you hoping to achieve? Better aeration?

Greg

The main thing is being able to swap tips at will according to requirements, or maybe to play until I can find a single tip satisfying all requirements.

The steamer comes stock with a single 0.75 mm hole in the tip. I could consistently get heavenly silky microfoam with it, but it would take about 45 seconds for 180 mL milk, in which time I would be watching the crema on the poured espresso slowly disappear .

I drilled out the hole to 1.2 mm and wow!! 15 odd seconds now. Definitely more consistent throughout and it marks better. Has the power to see some more vertical action going, giving more of a vortex than just a horizontal swirl.

But! For a single 180 mL in a 400 mL pitcher, as you can imagine, it's hard to contain the power. I muck up probably 2 in 3. It's perfect when I'm steaming double the milk in a larger pitcher though for two people, whereas the old tip would take minutes.

So I think with some experimenting I'll find a good solution.

Originally Posted by Michael G

Worth noting that M10x1 is not a standard thread (except in Japan). The die is likely to be a special order. You would be far better finding someone to make this for you - tapping S/S can have some tricks too.

But as Greg (the man who sets the bar for baristas) asks, why?

Michael

G'day Michael, actually M10 x 1 is a very common thread, it just may not appear so. Almost every modern geared bicycle uses an M10 x 1 thread on the rear derailleur hanger, so next time you see a bicycle you can think "M10 x 1" It also just happens to also be the standard fitting on commercial espresso machine steam wands.

I have a commercial espresso machine plumbed in to my kitchen that was bought as an "ebay bargain, in good condition". The reality was of course quite different and I would hate to have drunk anything coming out it, it required a complete rebuild. Every nut, bolt and fitting was removed and reconditioned, the frame painted (it was sadly before I could powder coat) and parts replaced or manufactured. I made some in stainless steel and some in brass. Of the two I would definitely recommend brass, it's much easier to work, especially at some of the fine hole sizes required (0.2 mm in stainless is nerve wracking on a full size lathe!). In my experience many of the fittings on commercial machines are brass, and chromed brass, the chroming simply for looks and make it easier to clean for the areas seen.

If I were in the OP's position, if you're certain it's M8 x 1 thread (and not standard x 1.25), I would buy that tap and some suitable diameter brass rod, drill and tap it, then chuck it in the drill and use a linisher or sander fixed in position to shape and polish the brass to a suitable shape. Then finally take a Dremmel or similar tool and drill a SINGLE fine hole in the end. You will probably find the commercially available steam tips have multiple holes and may produce disappointing results on a small boiler such as you're using, as it just can't produce sufficient steam to attain adequate velocity from the multiple holes. The solution is to either have finer holes (and that brings its own set of problems), or just one or two holes.

Have you tried simply buying a replacement tip in 8 mm? Along with Greg, my first reaction was to wonder what you're trying to achieve, but if it's just a replacement you're after they are available here Coffee Parts | Spare Parts for Espresso Coffee Machines - 2 hole and 4 hole Steam Tips

Hope that helps.

Pete

PS I recall at least one company circulating a while back who made so called (gold tips) for machines. No idea if they're still around as I don't tinker much in this area anymore. However I believe the "gold" part of it was simply polished brass, so there's no good reason it shouldn't look good.

Originally Posted by Zwitter

I did something similar on a steam wand. My wand is chrome plated brass not stainless. I bought a replacement nozzle and a threaded adapter from a coffee parts place and silver soldered it on. Still going strong.

I would however say that those kind of coffee pots may struggle to drive enough steam for bigger and more holed nozzles.

James

The pot's amazingly strong actually--it's a 1.2 L boiler typically filled with 0.8 L water, so on par with many boilers in $2000 HX machines. It's recovery is shocking of course, being only powered by a gas cooktop with the equivalent of a 330W heating element, but that's not an issue at home.

I saw a page of fittings at Coffee Parts | Spare Parts for Espresso Coffee Machines - Fittings but most appeared to be imperial. Is that where you bought your threaded adapter?

If you silver solder the fitting, be sure to use a grade of solder that is rated as suitable for food.
I like the idea of the threaded adaptor though.

Originally Posted by Pete F

If I were in the OP's position, if you're certain it's M8 x 1 thread (and not standard x 1.25), I would buy that tap and some suitable diameter brass rod, drill and tap it, then chuck it in the drill and use a linisher or sander fixed in position to shape and polish the brass to a suitable shape. Then finally take a Dremmel or similar tool and drill a SINGLE fine hole in the end. You will probably find the commercially available steam tips have multiple holes and may produce disappointing results on a small boiler such as you're using, as it just can't produce sufficient steam to attain adequate velocity from the multiple holes. The solution is to either have finer holes (and that brings its own set of problems), or just one or two holes.

Have you tried simply buying a replacement tip in 8 mm? Along with Greg, my first reaction was to wonder what you're trying to achieve, but if it's just a replacement you're after they are available here Coffee Parts | Spare Parts for Espresso Coffee Machines - 2 hole and 4 hole Steam Tips

It was just me planning to put the 1 mm pitch on the M8. I did that because I don't have a 6.8 mm drill bit, only a 7 mm, and thought never tapping before I'd probably snap the tap. The tap and die sets I initially looked at seemed to cater for both 1 mm and 1.5 mm pitches in M8.

I did look at the 8 mm tips, unfortunately they all (including at the link you posted) seem to have male threads.

Unfortunately I'm running for a flight, so don't have much time, but a 7 mm drill will be fine. The 6.8 mm is the theoretical spec size for full depth thread, rather than snapping the tap you're actually giving yourself more wiggle room by using a 7 mm. I routinely go a couple of tenths (mm) over size on my tapping drills if it's a non critical thread as it makes tapping much easier. You won't get full thread depth, but that is immaterial in many applications, including this one.

Yes sorry for casting the fur ball, all of my machines have been standard M10 x 1 and while I knew the M8s were out there I forgot the tips were male. Making up an M8 x 1 Female to Female coupling by tapping straight through some brass would be a possible solution, albeit one you'll see from the outside.

Incidentally, if you don't mind me asking, why are you doing this?

Pete

Ah yes, 7 mm is a bigger hole than 6.8 mm, isn't it

Incidentally, if you don't mind me asking, why are you doing this?

You may have missed post #8, as being a new member here, my posts need approval before they appear.

What external diameter is the actual steam pipe ?

If you are sure this is going to work, I would just cut off the pipe by the existing connector and solder on a 10 mm female connector.

It would look a hell of a lot neater.

Why even bother with an adapter ?

Rob