parallel & taper threads

[Dave2010]

guys,

I know this may be daft for most but I was wondering, with any male parallel how do you go about sealing to female parallel correctly? Should a washer/o-ring/fibre be at the bottom of the threads or at the top under the hex bit??

and can somebody share a link as to what the actual item used is to seal?

I was also wondering is there a real need anywhere to use male parallel fittings? Can somebody please advise when it would be used over a taper? I know female parallel exist but so far I aint had to deal with one.

thanks

 

[MANDATE]

When joining pipe where the threads are the seals, you don't really want large clearances which need filling with sealant, ptfe, hemp or lock nuts

The correct method would be to reduce the clearance by having a tapered thread although some form of sealant would still be required.

As far as I can recall it was the 'male' that would be tapered.

There are tapered male threads that don't seal as they should because they are too small in diameter.

If the seal is made using a end sealing face with washer or olive, then the threads dont seal and no tapered threads should be involved.

 

[Blagard]

I was also wondering is there a real need anywhere to use male parallel fittings?

Frequently hot water cylinders may have female threads for water inlet outlet and they also come with a warning not to use a tapered thread for connection. So you use parallel

 

[MANDATE]

I was also wondering is there a real need anywhere to use male parallel fittings?

Frequently hot water cylinders may have female threads for water inlet outlet and they also come with a warning not to use a tapered thread for connection. So you use parallel

That's understandable! Using a tapered thread the parts come up hard to each other, leaving little room for adjustment to get pipework pointing in the correct direction on the one hand, and over tightening could result in damaged cylinder.

 

[Dave2010]

If the seal is made using a end sealing face with washer or olive, then the threads dont seal and no tapered threads should be involved.

would a 1/2" tap connector be an example of this cause this seals using the rubber or fibre washer??

Frequently hot water cylinders may have female threads for water inlet outlet and they also come with a warning not to use a tapered thread for connection. So you use parallel

are these female threads parallel also? and if so do the male fittings have washers or just wraps of ptfe?

so for example if you were to use this fitting http://www.wickes.co.uk/content/ebi...m-x-1-2-MI-Coupling-DZR-Compression_large.jpg

what would you use to seal it into a female parallel? would you need a washer that goes over the threads and seats beneath the flange?

thanks guys

 

[Blagard]

On a cylinder the threads would typically be parallel female of 3/4" or 1" size. The similar male fitting in this instance uses thread sealing for the connection. Traditionally boss white and hemp, but these days PTFE tape or Loctite55 are often used.

While this may seem at odds with descriptions that say you use washers either on an end or a flange it does none the less work!

Interesting I went to the loctite55 web site to see if it said anything, but in the end just watched the video that shows a male parallel being used. While the female thread could be tapered it is unlikely.

http://www.loctite55.co.uk/?FOLDERID=18065

 

[MANDATE]

If the seal is made using a end sealing face with washer or olive, then the threads dont seal and no tapered threads should be involved.

would a 1/2" tap connector be an example of this cause this seals using the rubber or fibre washer??

Frequently hot water cylinders may have female threads for water inlet outlet and they also come with a warning not to use a tapered thread for connection. So you use parallel

are these female threads parallel also? and if so do the male fittings have washers or just wraps of ptfe?

so for example if you were to use this fitting http://www.wickes.co.uk/content/ebi...m-x-1-2-MI-Coupling-DZR-Compression_large.jpg


what would you use to seal it into a female parallel? would you need a washer that goes over the threads and seats beneath the flange?

thanks guys

Tap connectors: sealed by washer, threads parallel
Wickes coupling: sealed by washer against flange, threads parrallel.
As far as I'm aware all female threads are parallel whereas male threads may be tapered according to the method of sealing

 

[Blagard]

Wickes coupling: sealed by washer against flange, threads parrallel.

Whilst this is a technically correct answer you will not find any washer to fit it at Wickes or probably any other retail outlet. You need a 1/2" BSP external washer to fit using the flange and a washer for sealing.

Also of interest I have yet to see any such fitting actually supplied with a washer, so what do they expect you to use?

The only 1/2"BSP external washer you will find easily are the poly or rubber ones used for tank connectors which tend to have a larger suitable flange for that type of washer. I would expect to use a fibre washer for flange sealing the "wickes" type of flange.

As this is a DIY forum what would you recommend the DIY'er use?

 

[Agile]

Although cylinders are now more often being supplied with compression connectors the heating coils particularly and often other connections have been with parallel male threads.

These have often been difficult for people to seal using modern materials. Traditionally they were sealed with the hemp and jointing compound.

They are now usually sealed with many turns of PTFE tape or sometimes by the Loctite 55.

 

[MANDATE]

Wickes coupling: sealed by washer against flange, threads parrallel.

Whilst this is a technically correct answer you will not find any washer to fit it at Wickes or probably any other retail outlet. You need a 1/2" BSP external washer to fit using the flange and a washer for sealing.

Also of interest I have yet to see any such fitting actually supplied with a washer, so what do they expect you to use?

The only 1/2"BSP external washer you will find easily are the poly or rubber ones used for tank connectors which tend to have a larger suitable flange for that type of washer. I would expect to use a fibre washer for flange sealing the "wickes" type of flange.

As this is a DIY forum what would you recommend the DIY'er use?

For the DIY'er If no washer available, you have to either make one if you can or use the ptfe tape. Problem is with tape you may not seal fully depending upon how many turns you apply and that depends how good or poor the fit is between the components. Also where flanges are involved ptfe tape can be wrapped between the sealing faces in lieu of a washer before tightening the last couple of turns.

 

[Steelmasons]

Although cylinders are now more often being supplied with compression connectors the heating coils particularly and often other connections have been with parallel male threads.

These have often been difficult for people to seal using modern materials. Traditionally they were sealed with the hemp and jointing compound.

They are now usually sealed with many turns of PTFE tape or sometimes by the Loctite 55.

The correct fitting to use would be the 'CU68' , not difficult at all. either use the tapered or flat face seating dependant on coil.

 

[Blagard]

The correct fitting to use would be the 'CU68' , not difficult at all. either use the tapered or flat face seating dependant on coil.

Please post a link to examples at suppliers

 

[Steelmasons]

Google it , jeez it's a standard fitting in relation to the plumbing/heating industry.

 

[Blagard]

Google it , jeez it's a standard fitting in relation to the plumbing/heating industry.

Jeez I did! before posting and searched my suppliers. but I reckon the term is now out of use and the fitting may be called something else.
So come on be helpful and show what you are talking about!

 

[Steelmasons]

Sorry but I can't do links as I'm computer illiterate , 'my suppliers' you state? , do you work in this industry? , I would say not considering you don't know what a CU68 is , it looks very much like a 15mm tap con that utilizes a ¾ union nut.

Upon reading your postings it is quite clear you are not shy of google.