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Angle of blowpipe valve seat

PostPosted: Sun May 29, 2011 7:31 pm
by pipemakermike
Does anyone have a view on the relative merits of the square flap valve seat as shown on the Dunn original compared to the angled version that I have commonly used?

Re: Hello

PostPosted: Sun May 29, 2011 9:30 pm
by Barry Say
What do see as the advantages of the angled end?
Personally, I regard it as an unnecessary complication as it means that the flap must be elliptical rather than circular.

Re: Hello

PostPosted: Sun May 29, 2011 9:47 pm
by pipemakermike
My use of an angled end is probably influenced by the use of the Cocks & Bryant book as the first place I found making information. There are 3 blowpipes drawn in that excellent book and they all have angled ends. I didn't really think about it until Nick Leeming was helping me check some parts and asked me why the end was angled and I didn't have a good answer.
Thinking about it now and with my engineer's hat on I would guess that the flap has to move through a smaller angle to open to a reasonable aparture than would be necessary on a right angles flap and it is possible that the force required to open it is smaller (this is a guess and may be nonsense<G>)

Re: Angle of blowpipe valve seat

PostPosted: Mon Jul 04, 2011 10:43 pm
by Barry Say
Traffic on this list is slo-o-o-ow, so this is a late reply.

C & B must be taken cum grano salis. It is possibly in the words of the white knight - Something of my own invention.

I always presumed that the idea was that there would be an element of gravity closing the valve. With an angled seat the flap wants to fall onto the seat, whereas with a square face the valve could naturally sit a degree or 2 off closed, requiring bag pressure to achieve a seal. I think this argument is specious.

I learnt my pipemaking predominately with Colin Ross who always uses square ends although I can never remember any discussions on this point.

In my opinion, angled ends lead to difficulty of maintenance. It is certainly inconvenient to use a lathe centre on a piece with an angled face, and the valve flap is more difficult to construct.

If I have a set of pipes through my hands which will go out with my guarantee, I have always squared of the blowpipe seat. Of course I would not do this with a set which had historical significance. I have never found any problem with squared ends.

Any further thoughts anyone?


Re: Angle of blowpipe valve seat

PostPosted: Tue Jul 05, 2011 10:22 am
by Julia Say
Insofar as I can remember Colin's thoughts on the matter, it was simply "not necessary" to angle the ends.


Re: Angle of blowpipe valve seat

PostPosted: Tue Jul 05, 2011 1:02 pm
by Francis Wood
There is no practical advantage in an angled end. The 90 degree end suited the Reids and Dunn just fine, and I see no reason to 'improve' on their practice.
I'm not even convinced by the gravity aspect, i.e having the leather hanging down. It makes not the slightest difference to the valves I make. I'd always advise anyone to insert the blowpipe correctly, i.e. with the leather hanging because in some instances it may make a difference, though with a carefully adjusted example it really doesn't seem to matter.

Re: Angle of blowpipe valve seat

PostPosted: Wed Sep 21, 2011 5:54 pm
by andymay
The angled valve is less prone to being noisey, and less prone to getting stuck.

I choose to use a blowpipe end which is very much angled (45?) for these reasons.

I was able to cure the noisey valve of a well-known piper by sawing a bit off the blowpipe to angle the valve.

Each to their own....


Re: Angle of blowpipe valve seat

PostPosted: Fri Dec 09, 2011 1:35 am
by adrian
I have a view. Let it dangle; the valve is proficient over the player and the player gets knowwhere with the valve.
The valve has to seat at an angle to seal-without player introvention.