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Key for 5/16" Drain Cock


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The drain cock on our Ellis Heatmaster has a 5/16" square headed tap which has to be turned about three revolutions before anything approaching a decent flow can be achieved.

 

The problem is that this has to be done with an open ended spanner as I have been unable to find anyone who can supply a 5/16" square socket or key. I can find 1/4". 3/8" 1/2" and 3/4" but not 5/16" which seems to be the standard size for this type of fitting,

 

Does anyone know where I can obtain a suitably sized key or socket to fit one of these:-172121_wpdp.jpg

Edited by David Schweizer
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Not that it would make it much easier than an open ended spanner though

 

Richard

 

I have one which consists of two square sockets on oppsite ends of a bar, with their own universal joints. Haven't checked the sizes, or whether they are still available.

 

Tim

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Thanks for all the Suggestions, I had seen the Screwfix four way spanner, but as richard states with no size details the adver is not very helpful. However, I am following several brake adjusting socket spanners on ebay, so thanks for the links

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A bi hexagonal socket or a ring spanner will operate on a square. Worth a try, but getting the correct size may be trial and error as the covers of the valve steam are often chamfered.

 

Yes I have tried one of those and 9mm fits although it is a bit loose, but if all else fails I could use it.

As a slightly different angle, and if space allows, how about using a tap holder from a tap and die set.

 

T-S%20724%20Tap%20Holder%20RN.jpg

 

$T2eC16hHJGcFJmYGqH5jBScDHh05F!~~60_35.J

 

both only just over a £5

 

Yes I thought of tap wrenches, and have a selection of both types in my workshop, However, there are a couple of problems with them as threading taps have either a 1/4" or 3/8" square end, The first type illustrated could be encouraged to fit, but there is insufficient room to turmn one, and the chuck on the second type is either too big, or too small.

Edited by David Schweizer
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The drain cock on our Ellis Heatmaster has a 5/16" square headed tap which has to be turned about three revolutions before anything approaching a decent flow can be achieved.

 

The problem is that this has to be done with an open ended spanner as I have been unable to find anyone who can supply a 5/16" square socket or key. I can find 1/4". 3/8" 1/2" and 3/4" but not 5/16" which seems to be the standard size for this type of fitting,

 

Does anyone know where I can obtain a suitably sized key or socket to fit one of these:-172121_wpdp.jpg

 

I undo these on a regular basis draining boilers to swap heat exchangers etc.

 

The effect you describe where three whole turns are needed to gewt anyting out is caused by over-tightening them in the first place. The neoprene washer sticks to the seat and the jumper pulls away from it, leaving the 3mm diameter ventre hole in the washer for the water to flow though.

 

Next time you drain it take the plug RIGHT out and you'll find the washer still inside stuck to the seat. Rake it out, fit a new washer than tighten it only a little more than finger tight for a good water seal, and rapid draining next time you use it.

 

MtB

http://www.ebay.co.uk/itm/Silverline-8mm-Metric-Polished-Combination-Spanner-Buy-One-Get-One-Free-8-mm-/351247415826?pt=LH_DefaultDomain_3&hash=item51c7fa3a12

(my preferred spanner for opening these.)

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How tight is this thing? If a 5/16 spanner will fit and turns it why not use it.

 

Darren

 

Tightness is not an issue. The issue is the number of times the spanner needs to be put back onto the tap to close it, because of restricted space which only allows for a quarter turn each time. A socket on an extension would allow close down and re-opening to be performed far more quickly.

 

I undo these on a regular basis draining boilers to swap heat exchangers etc.

 

The effect you describe where three whole turns are needed to gewt anyting out is caused by over-tightening them in the first place. The neoprene washer sticks to the seat and the jumper pulls away from it, leaving the 3mm diameter ventre hole in the washer for the water to flow though.

 

Next time you drain it take the plug RIGHT out and you'll find the washer still inside stuck to the seat. Rake it out, fit a new washer than tighten it only a little more than finger tight for a good water seal, and rapid draining next time you use it.

 

MtB

http://www.ebay.co.uk/itm/Silverline-8mm-Metric-Polished-Combination-Spanner-Buy-One-Get-One-Free-8-mm-/351247415826?pt=LH_DefaultDomain_3&hash=item51c7fa3a12

(my preferred spanner for opening these.)

 

The washer may be stuck to the seat, but it has been there for more than 30 years, I supspect that it might also have something to do with the fact that the boiler casing gets very hot, and the drain cock is only inches away fromn the burner

 

The size of the spanner is also not an issue, I have spanners of all sizes, (including some odd cycle and motorbike sizes) it is the type, which is important. What i want is a 5/16" square socket, I already have plenty of open ended ones which are slow and cumbesome to use in the space available.

Edited by David Schweizer
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A 12 point 5/16 1/4 drive socket and a 1/4 drive ratchet will fit fine.

 

No it won't. I've tried that. A 9mm will fit, but it is a bit sloppy, an 8mm is too small.

 

 

 

 

$_57.JPG

 

 

Yes I am watching that one but the 1/2" socket is a bit oversized. I have only ever used 3/8" and 1/3" drive so by the time I have added socket reducers it would be massive.

Edited by David Schweizer
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Easy to make a kind of crows foot spanner. From a strip of say 2 or 3mm steel cut slightly undersize the 5/16'' slot with a junior hacksaw in one end. Cut out with a sharp cold chisel or bend out the waste tang and cuCt off, file up slot to 5/16''. On the other end of the strip cut out in a similar fashion a slot for your preferred extension bar drive size, 1/4''-3/8''-1/2''. A square hole could be made for the socket bar drive, but a slot for it will do the trick. Finally in a vice bend the strip at both ends crows foot fashion.

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