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Oleo Strut Valve

PostPosted:Thu Apr 18, 2019 11:43 am
by Antair
On my Bölkow 207 the strut valve is a little different to the usual Schrader valve. It has a 13.25mm male thread and requires, I believe, the core to be depressed by a spindle on a special tool. I need to make the tool and would like to start by ascertaining if this valve is likely to be metric, american, bsp etc. Nothing I have tried so far really fits right.
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Re: Oleo Strut Valve

PostPosted:Thu Apr 18, 2019 1:26 pm
by cockney steve
I'm assuming that Bolkow is Eastern Bloc, therefore likely to be Metric. The thread into the Oleo is likely just that, a standard Metric profile and pitch.
the "connector"end is possibly a different story, but at first glance appears ti bear a marked resemblance to a disposable gas-cartridge connection.

Thread -pitch gauges are available in Imperial, unified and metric sets. rather like a set of feeler-gauges, they have a serrated end-section on each blade. Select a near match and try it in the threads you wish to identify. (or you could manually count the pitch

wrap a clean strip of paper tightly around the projecting threads, rub with a dirty finger and you will transfer a series of lines , corresponding to the threads (think brass-rubbing!)

As almost everything is standardised, I'd take a wild guess that it's a metric pipe thread.

There is bound to be a tutorial on thread- identification , on the net. note the first couple of threads at 6-o'clock have been damaged If a correct connector will not fit, the damage can be dressed-out with a swiss file (ebay,screwfix and many others)

Re: Oleo Strut Valve

PostPosted:Fri Apr 19, 2019 9:14 am
by Antair
Thanks for taking the time to reply cockney steve, I will measure it up, but it seems to be close to a number of standards. I doubt it is exclusive to Bölkow and would be fairly common on other German aircraft.

Re: Oleo Strut Valve

PostPosted:Fri Apr 19, 2019 11:33 am
by cockney steve
I'd suggest Euro Hydraulics or a similar outfit,such as a heavy -plant repairs/spares specialist.
As you observed, it's unlikely that someone re-invented the wheel when someone's all geared up to make them cost- effectively and robust. but it does happen!

Re: Oleo Strut Valve

PostPosted:Fri Apr 19, 2019 10:49 pm
by MikeW
Is it 1/4" BSP? Major diameter 13.157mm, 19tpi. Or 1/4" NPT (or NPS), 13.716mm, 18tpi? I can't match 13.25mm exactly.