Twin Piston Oil Pump Project

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Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Twin Piston Oil Pump Project

Post by Pipescs »

I did order two 4mm Torrington Clutch assemblies. Not too impressed as they are very inconsistent and slip a piece of 4mm precision ground rod that came with them.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
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Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Twin Piston Oil Pump Project

Post by Pipescs »

Starting to pull the pieces together for the big test. My only concern is will there be enough piston travel to get that one drop of oil per revolution of the eccentric shaft.

This a photo of the eccentric and ratchet wheel that Pontiacguy turned out.
DSC_4526.jpg
The original design called for a piston of .157 diameter for a one and a half inch scale engine. It was only a single pump design. So I have dropped the piston size to .125 but added a second pump.

The ball check valves are in place in the bottom of the pumps and I will hopefully plumb it up (excuse me, Pipe it up) this week end and run a test of the pumps on the shaft to see the quantity it pumps.

Two variables at this point are piston length and if all else fails, I could change the throw on the eccentric for more travel past the pick up ports
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
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Steggy
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Re: Twin Piston Oil Pump Project

Post by Steggy »

Pipescs wrote:I did order two 4mm Torrington Clutch assemblies. Not too impressed as they are very inconsistent and slip a piece of 4mm precision ground rod that came with them.
What do you mean by "as they are very inconsistent"?

Drawn-cup roller clutches (what I believe you are calling a "Torrington clutch") are trustworthy devices if correctly utilized. The clutch itself has to be a press fit into its supporting member (refer to the manufacturer's data sheet for fit recommendations) and the mating shaft's diameter has to be closely held, generally nominal clutch ID minus 0.001 to 0.002 inches. The contact surface should be be finished to 16 micro-inches or better, with a recommended surface hardness of Rockwell 55C to 60C. In the past, when I have used a drawn cup roller clutch in power transmission designs, I have made the shaft from C1144 TGP and after case hardening the clutch contact surface, polished it with oil and crocus. I have never had a failure.

Roller clutches cannot be run dry, so some provision for lubrication is necessary. Also, a roller clutch cannot act in lieu of a bearing if the shaft is radially loaded. Failure to use one or more bearings in such situations is a frequent cause of clutch failure. Most drawn cup roller clutches use a non-metallic roller cage, which typically limits the maximum operating temperature to 200-or-so degrees F. Exceeding the temperature rating will cause the cage to fall apart or melt, allowing the rollers to skew and ruin the shaft.
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Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Twin Piston Oil Pump Project

Post by Pipescs »

On the Drawn-cup roller clutches, we will definitely talk more. Talking with Scott last night, it is apparent I have a shaft material that is under sized too much. The clutch slips intermittently when rotating dry. I will do one two inch prototype with the ratchet wheel and one with the clutches.

ordering new material for the project this week so I will order some 4mm shaft material of the shaft from C1144 TG. I assume by lubrication you are talking grease or heavy oil. Does steam oil on it count?
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
User avatar
Steggy
Posts: 1973
Joined: Tue Jun 28, 2011 9:19 pm
Location: JB Pritzker’s Hellhole
Contact:

Re: Twin Piston Oil Pump Project

Post by Steggy »

Pipescs wrote:I assume by lubrication you are talking grease or heavy oil. Does steam oil on it count?
Typically, motor oil or similar is used as a lubricant. Steam oil ought to work, especially considering the low speed operation the clutch will see, as long as the viscosity isn't too great. EP lubricants are also usable, although gross overkill. Grease is generally not recommended and may cause the clutch to malfunction.
———————————————————————————————————————————————————————
Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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