Elmer's Centrifugal Pump

[agr]

Having recently finished my third of elmer's engines I was looking for the next project to tackle. Browsing through my library of "some day" projects I came across Elmer's Turbine/Pump set. While not real interested in the turbine itself, I thought the pump itself would make a good project of its own, giving my other engines something to drive & to show them doing real work.

I thought the pump would also give me the opportunity to practice some techniques not used to date - such as boring a blind hole, and a chance to try out my new rotary table.

In addition, since the design has a low part count, I thought I'd try making two at the same time to see if I was capable of producing two of each part to the same dimensions (within reasonable tolerances )

To start I cut two pieces of 6061 aluminium & milled to size (1-1/4 sq) & marked out

These were then centred in the 4-jaw (eventually), drilled through 1/4" & then bored out.

So far so good, both cavities were slightly oversize, but both the same (within .02mm). The first one went well, but the second seemed to chatter a little (even after a rub on the tool with the diamond file) but as its not a piston bore I wasn't too concerned with finish.

They were then reversed, re-centred and the back turned down to form the bearing spigot

Digging through the scrap box I found some 1-1/2 aluminium bar & turned down the two "heads".

This completes the progress for one weekend, hopefully time will allow further progress new week

Tony.

 

[agr]

Well a little more progress to date, albeit rudely interrupted by the failure of my mill's DC Drive (see http://www.homemodelenginemachinist.com/index.php?topic=15501.msg159030#msg159030)

The blanks for the impellors were machined down to size & parted off (seems a waste of 1" alluminium bar when the parting tool is as wide as the piece your parting off) and marked out.

This then gave me a chance to test out my rotary table to drill the 6 1/8" holes that form the start of the gaps between blades.

Then, after drilling and tapping the mounting holes and outlet fitting hole in the pump bodies I attempted to mill the bodies to shape while the rotary table/mill was still setup. This is one of the disadvantages of owning a combo mill/lathe, you either are constantly converting between mill/lathe setup, or you have to plan the work such that you do a batch of milling, then swap over and turn as much as possible, then back to mill setup...

I had almost finished the first body when the aforementioned disaster struck - after the repair to the invertor drive I was able to manage to finish the first body, but the second is still in waiting.

Unfortunately for some reason the shape of the first body wasn't as good as expected and has a distinct, non-roundness to it. I don't know if this was becuase my mounting to the rotary table wasn't secure enough, or if perhaps I bumped the lathe saddle/cross slide during the removal and replacement of the drive ciruit board? Anyway, I think a bit of filling will bring it to a reasonable shape when done.


Been out of state the last two weeks with work and again next week so progress has all but stopped for the time being plus I still need to order some stainless rod for the shafts. But that is one of the goods things with this hobby, doesn't matter how long your absent from the shop, everything is still as it weas when you left, ready to continue.

Tony.

 

[vascon2196]

I love building Elmer's Engine!

Keep it going!!!

Chris