Brass connectors with "serrated" threads (why?)

[davblo]

Hi,
I've been buying parts for a water purification system and notice that some of the brass fittings with external threads (they are size G25 = 1") have regular serrations on them.

Here are a couple of pictures...

Other fittings I see available do not have these features....

I've searched and searched but find no explanation of the serrations.
I'm a bit concerned about their effect on tape I intend to use for sealing them into other components.

Has anyone seen this before and know what it is for?

 

[Deleted member 120897]

It’s not something I’ve seen or noticed before, perhaps it’s the price, and therefore quality?

 

[davblo]

Thanks, but I'm pretty sure it's not a price thing. They are very regularly spaced and appear to have been made deliberately.

 

[Deleted member 120897]

Do you have a link, or brand name?

 

[ShaunCorbs]

For loctite 55

It allows the cord to be grabbed

 

[mattfrance]

it's because the fittings are used in other countries where they still use hemp and paste. The threads are roughed up to stop the hemp from slipping when you tighten the fitting.

In France, hemp and paste is the norm, and if we buy fittings that haven't had the threads roughed up then we have to do it ourselves with a hacksaw blade.

 

[davblo]

Do you have a link, or brand name?

The actual picture on their web page just shows plain threads, but I found another related site which does show the serrations....

Köp Vatette Koppling Rak Utvändig Gänga Gul - VVS home.se

Vattete Rak Klämringskoppling Med Invändig Gänga - 35 års Erfarenhet - Snabba leveranser – VVS home.se

www.vvsobadrum.se

As you will see these are Swedish products.

 

[davblo]

it's because the fittings are used in other countries where they still use hemp and paste. The threads are roughed up to stop the hemp from slipping when you tighten the fitting.

In France, hemp and paste is the norm, and if we buy fittings that haven't had the threads roughed up then we have to do it ourselves with a hacksaw blade.

Thanks! I did wonder whether it could be that kind of reason.

So my question is whether it will be ok to use tape, or will it shred the tape and cause the joint to leak?

 

[Deleted member 120897]

It appears Shaun and Mattfrance have answered better than I can

 

[exedon2]

Why not just use loctite 55 ? So much better than ptfe!

 

[Ric 2013]

I scratch the threads for ANY thread-sealed fitting so think you will be absolutely fine with tape. You need plenty of turns, but you'd need plenty of turns even without the serrated threads. Serrated threads is usually a sign of quality.

 

[davblo]

Why not just use loctite 55 ? So much better than ptfe!

Is it?
I've used tape a bit but never the glue type sealants - just sounds a bit messy; and I've heard tape is easier to clean off if you have to re-do a joint.

I did order one of these in case I needed it...

Loxeal 55-03 Blue 50 ml Thread Sealant

Buy a Loxeal 55-03 Blue 50 ml Thread Sealant online from Tameson today. Same day shipment with global shipping options.

tameson.com

It's not loctite 55 but I guess it will do the same job.

 

[ShaunCorbs]

Loctite 577 is liquid

 

[WC1]

Loxeal sounds the same as 577 - "anaerobic" so it goes off when o2 is excluded i.e. inside the threads.
577 is awesome btw

 

[davblo]

Loxeal sounds the same as 577 - "anaerobic" so it goes off when o2 is excluded i.e. inside the threads.
577 is awesome btw

Thanks!

I was wondering what could possibly initiate the hardening - especially as it says "anaerobic".

You mention exclusion of O2, but how is inside the threads any different from inside the plastic container it is stored in?

 

[Ric 2013]

Loctite 55 is not a liquid. It's a kind of string.

 

[davblo]

Thanks!

I was wondering what could possibly initiate the hardening - especially as it says "anaerobic".

You mention exclusion of O2, but how is inside the threads any different from inside the plastic container it is stored in?

I searched myself and found....

"LOCTITE® threadlockers cure in the absence of air and presence of metal ions."

So the metal plays a part as well.

There is a list of "inactive" metals where a primer is recommended but brass and copper are amongst the active ones, so no primer needed.

 

[WC1]

Looking at the 577 bottle, im not sure its particularly air tight. Certainly theres no metal inside. I was doing a job at my dad's yesterday and he was fascinated by 577.