Author Topic: A hydraulic hand pump  (Read 6512 times)

Offline Firebird

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A hydraulic hand pump
« on: July 26, 2012, 08:11:28 PM »
Hi

Heres a few photos and some plans of a pump I built a while back to test my small boiler. I will use it again to test the boiler on my portable engine.









All the parts layed out on an enlarged plan



Any questions please ask, I have more photos and details.

Cheers

Rich

Offline arnoldb

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Re: A hydraulic hand pump
« Reply #1 on: July 26, 2012, 10:32:38 PM »
Thanks for showing your pump and plans Rich  :ThumbsUp:

Having built one myself to your plans (not as good looking though!) and after pressure testing a couple of boilers with it, I can really recommend it  :NotWorthy:

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline smfr

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Re: A hydraulic hand pump
« Reply #2 on: July 26, 2012, 11:58:41 PM »
I read that when building the Stuart hydraulic pump, you have to be really accurate. Is it just that the piston needs to be a very tight fit to the bore, otherwise it leaks?

Simon

chuck foster

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Re: A hydraulic hand pump
« Reply #3 on: July 27, 2012, 02:48:20 AM »
thanks for the plans rich  :ThumbsUp: and as usual that is a mighty fine looking piece you have made.

chuck

Offline Bearcar1

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Re: A hydraulic hand pump
« Reply #4 on: July 27, 2012, 11:00:50 AM »
I remember when you built that Rich,......... NICE!  :ThumbsUp:

BC1
Jim

Offline Firebird

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Re: A hydraulic hand pump
« Reply #5 on: July 27, 2012, 07:24:25 PM »
Hi

Thanks gents.

Simon, the piston needs to be a nice sliding fit in the bore. The piston here is stainless steel and is bang on .25 so all I had to do was carefully ream the bore. The trick is getting the O ring groove right. The O ring in this case .25 OD with .125 ID making the walls of the O ring (if thats the right term) .0625.  When turning the groove in the piston it must be slightly larger than .125 so that when the O ring is fitted it is slightly larger than .25 and therefor makes a good seal when squashed into the bore. Although the plans show the O ring groove to be .0625 wide it does in fact need to be slightly wider so that when the O ring is squashed down, making it oval in section, it has an equal amount of room to move sideways. I think I'm right in saying that O rings won't compress but just change shape. A quick search on google and you will find plenty of info re O ring groove sizes.

Cheers

Rich