Radiator drain tap - tapered or straight fit?

[Pete Lewis]

flanders and swan  painted over the gas tap 

same sort of tap

when /what year did the tap get  replaced with the plug 

 

[Colin Lindsay]

1 hour ago, Pete Lewis said:

when /what year did the tap get  replaced with the plug 

No idea of exactly when, or if it was a short-lived variation; I've only ever had one and it's gone on the Estate. Neither the tap nor the plug are tapered, they're straight-to-the-end threads and need a washer.

[Stratton Jimmer]

20 hours ago, Pete Lewis said:

a good hand pull on  a normal spanner will get you a good night sleep

Very true! Spanners are the size they are to limit the torque that can be applied with one hand for a bloke of average build and strength. We have tapered washout plugs on our steam locos (I volunteer on the S&CR as a loco fitter and driver). We only allow a small number of qualified staff to remove and refit these as it is so easy to cross threads or damage them by over tightening. These plugs are often of gunmetal and the only sealing compound allowed is graphite grease.

[Pete Lewis]

is that the Bluebell then  

Pete

[PeteH]

4 hours ago, Stratton Jimmer said:

These plugs are often of gunmetal and the only sealing compound allowed is graphite grease.

Cylnder Oil and Graphite, was a staple on the old Triple Expansion Steamers. Threads. Rods, and just about everything else.

What your water like? (hard soft), how often do you need to washout?. Some Traction Engine "owners" can go a whole season without, Then wonder why they have issues with seams.

Pete

[Wagger]

5 hours ago, Pete Lewis said:

is that the Bluebell then  

Pete

I had to look it up, but the S&CR is the Swindon and Cricklade Railway. The Bluebell is between Uckfield and Haywards Heath. It is the luckiest private railway locally to me as it was closed before the Beeching axe fell. It had a head start on most of th others. They do a super Pullman afternoon or evening meal. Family treated us for my 70th in 2017.

[Stratton Jimmer]

12 hours ago, PeteH said:

What your water like? (hard soft), how often do you need to washout?.

Our water is extracted under licence from the River Ray only some six miles from its source but between there and us there is a Thames Water treatment plant which processes the waste from the 200,000 or more individuals that live in the Swindon area. The water in consequence is very hard and high in nitrates. One of my colleagues who was a metallurgist with the CEGB specialising in turbine blades had the water tested and developed a scheme for water treatment. Use of this scheme is open to the owners of each locomotive and one in particular refuses to use it. His loco regularly develops leaking tubes, suffers from regulator blow through and has had the steam brake fail due to calcium deposits building up in the brake valve. It also primes a good deal. He tells us that "I know best what's good for my engine". He's an idiot! 

His loco requires washout every seven or eight steamings while others which use the water treatment regime go as many as twenty steaming between washouts.

[daverclasper]

On 06/01/2022 at 12:41, Chris A said:

The tap must have been kept closed by dirt and grit as it now opened far too easily ! I quickly ordered a plug and replaced it.

Do you know the size of the block plug you used please?. Had leak recently and couldn't trace it, though forgot about looking at the block drain tap.

[Chris A]

55 minutes ago, daverclasper said:

Do you know the size of the block plug you used please?. Had leak recently and couldn't trace it, though forgot about looking at the block drain tap.

Not at present, will need to look it up tomorrow but check out sites such as Rimmers as they are listed

[daverclasper]

Thanks Chris. It would be very handy to know the size, for possible alternatives. I do find it a killer for postage charges for a small item.

[Colin Lindsay]

Never ever buy any common-to-most part that's marketed for a particular car, the suppliers will have a field day! Roughly the same kind of tap is used on tractor engines and a lot cheaper than the £25 - £45 quoted for 'our' block taps:

https://www.ebay.co.uk/itm/133627904773?hash=item1f1cd80305:g:AfwAAOSwOkRf6yHf

However if you just want the plug:

https://www.ebay.co.uk/itm/292762384496?var=591547145833&hash=item4429ff7870:g:~A4AAOSwapdbu1LT

[daverclasper]

Thanks Colin. Is 1/4" BSP the correct size then?.

[Pete Lewis]

129077   is the plug   might be in the hardware catalogue  will look in the morning 

no its not in there 

Pete

[Colin Lindsay]

44 minutes ago, daverclasper said:

Thanks Colin. Is 1/4" BSP the correct size then?.

I'm going by the majority on here, but any of the drain taps I checked online before that post all claimed 1/4 BSP too.

[Colin Lindsay]

Well, I've committed. 1/4 BSP tap in 19tpi purchased and seems to work fine; with the wide Estate radiator there was minimal resistance, it screwed straight in, and the narrower 13/60 version that's just back from the reconditioners' had very slightly more resistance; all just fingertip pressure and the tap spun in very easily without the feel of cutting new threads. I trial-fitted two new drain taps and they went in only very slightly, maybe about 1/3 of their threads, before becoming finger-tight - I'm hoping this is due to the taper and not the threads misaligning...

  

 

[Wagger]

You can test these for leaks I am sure Colin. I have done this in the past by using neat antifreeze just enough to fill it above the tap, then pressurising it after blocking the other holes. Can't remember what poundage I used, but even lung pressure will do. It is Brass on Brass, so tweaking it up and releasing it a few times will bed the thread in if it does leak.  I used hermatite, but Hylomar should work. It does not set.

[68vitesse]

Had a drain plug in one car that had a flat on the first part of the thread, loosening the drain plug about half to two thirds would give a more controlled drain than needing to remove it completely.

Regards

Paul.