Allen axle pump

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crackerjackhoghead
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Allen axle pump

Post by crackerjackhoghead » Fri Oct 28, 2011 2:43 pm

I'm wondering if the Allen axle pump performs satisfactorily or If I should pursue something else. I will also have a pair of injectors.

Jeff

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cbrew
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Re: Allen axle pump

Post by cbrew » Fri Oct 28, 2011 3:04 pm

crackerjackhoghead wrote:I'm wondering if the Allen axle pump performs satisfactorily or If I should pursue something else. I will also have a pair of injectors.

Jeff

I never installed it on the American and will not on the ten wheeler. Two injectors (SuperScale) do the job just fine

Just my 2.5 cents
If it is not live steam. its not worth it.

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Trainman4602
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Re: Allen axle pump

Post by Trainman4602 » Fri Oct 28, 2011 5:55 pm

Axle pumps are a throw back to 1 inch and 3/4 scale they are not need in 1 1/2 scale. Two injectors are all that's need. The larger modern locomotives did not have them.

Axle pumps are noting but a pain
ALLWAYS OPERATING MY TRAIN IN A SAFE MANNER USING AUTOMATIC AIR BRAKES

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FLtenwheeler
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Re: Allen axle pump

Post by FLtenwheeler » Fri Oct 28, 2011 6:25 pm

Hi

I have an axle pump on my 10-Wheeler. I used a rubber cup that I purchased from Cole’s Power Models and a nylon O-ring in a grove behind that. I had the ball lift set to high at first but once I fixed that it has never giving me any problem. I do have 2 injectors that work great as well.

The pump puts most of the water I need in the boiler. Then I use the injectors to top it off once every other time around or so.

Tim
He who dies with the most unfinished projects: Should of put more time into their hobby.

Andy R
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Re: Allen axle pump

Post by Andy R » Fri Oct 28, 2011 6:27 pm

I agree with Chris and Dave.

My 7.5-inch mogul is a mongrel that incorporated many Harpur (pre-gene Allen) components. The axle pump siezed up on me during a meet. It was NOT fun trying to disconnect the eccentric under a hot locomotive in order to clear the main. I made a new pump to the same design. It ran well, and with the bypass cracked open, provided ample water. But it too siezed up, again during a meet. At least i had the tools available to disconnect the eccentric. I have since removed the pump and all the associated piping and use the Ohlencamp injector. Another injector is on order from Superscale.

The problem with big pumps is that they do not scale-up from the 3/4-inch scale locos. The rams need to be guided just like the steam pistons are guided ... but i've never seen a guided ram design for an axle pump.

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John_S
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Re: Allen axle pump

Post by John_S » Fri Oct 28, 2011 8:27 pm

I think it comes down to builder's choice for axle pumps.

My mogul has the eccentric on the axle, but I have no plans whatsoever of actually putting a pump on the loco. I'm going to put two injectors on and not bother with the extra work involved in the pump.

crackerjackhoghead
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Re: Allen axle pump

Post by crackerjackhoghead » Fri Oct 28, 2011 10:21 pm

I was hoping you guys would say that as I'd rather not put it on the engine. I thought I was going to be told not to rely on the injectors alone.

Jeff

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cbrew
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Re: Allen axle pump

Post by cbrew » Fri Oct 28, 2011 10:24 pm

crackerjackhoghead wrote:I was hoping you guys would say that as I'd rather not put it on the engine. I thought I was going to be told not to rely on the injectors alone.

Jeff
Just go with Superscale and have screens on the water supply lines to keep the chucks out and you will not issues.
If it is not live steam. its not worth it.

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David Powell
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Re: Allen axle pump

Post by David Powell » Sat Oct 29, 2011 5:38 am

While not quite relevqnt to the original question I would add that I have seen a number of axlepump arrangements on 3 1/2" gauge models which have given trouble or had short working lives, thanks to excessive angularity of too short eccentric rods. In a couple of cases I have solved such problems by rearranging the drive, using a longer dog leg shape eccentric rod, driven from a further away axle. to go above and around the axle nearest the pump. I will admit it looks a little strange, but it works smoothly, and the pumps seem to run for ages without attention to the gland packing. Hope this hint helps someone David Powell.

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Bill Shields
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Re: Allen axle pump

Post by Bill Shields » Sat Oct 29, 2011 6:18 am

Then I guess I am a 'throw-back'.

I have axle pumps, steam driven pumps and injectors, as well as a hand pump.

I like having a pump that I can set and forget while running.

Properly designed, there is no reason why an axle pump should give any trouble.

10 Wheeler Rob
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Re: Allen axle pump

Post by 10 Wheeler Rob » Sat Oct 29, 2011 7:28 am

The axle pump on the prints is will provide most of the water needed but is marginal in its sizing. This I confirmed with both caculation and the operqting experance of mogal operating at our club.

If you want the ability to run solely on axle pump(s) capacity I would recomend either increasing it to 5/8" bore form 1/2" or going with dual 1/2" pumps.

As mentioned previously one ejector will give you the capacity needed, a second the back up needed or safe operation. Ejectors have the advantage of being mounted where they can be easily maintained.

Rob

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Greg_Lewis
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Re: Allen axle pump

Post by Greg_Lewis » Sat Oct 29, 2011 3:54 pm

Well-known Nevada steamer Cal Tinkham has a 5/8 dia. ram pump on his engine and it's a set-it-and-forget-it arrangement. The injectors put out a lot of volume and require lots of on and off fiddling, but once the bypass is set on the pump all you need to do is pull the throttle and enjoy the view. The only time the injectors are used is when the engine has been sitting waiting for clear track ahead.

In the end everyone has preferences and it probably doesn't matter that much.
Greg Lewis, Prop.
Eyeball Engineering — Home of non-interchangeable parts.
Our motto: "That looks about right."
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