Chris's Holly Pumping Engine Build

[crueby]

They are sure a sizable flywheel in scale

I remember as an apprentice 55+ years ago [Saturday overtime  -  maintenance day] checking on the drip feed lubrication to the outboard bush bearings to two [2] large, low speed Broom & Wade air compressor, with each having a single flywheel [about 8' diameter - quite a bit taller than me] and each wheel had a series of 1/2" drillings around the outer edge near the major OD.......these were balance drillings performed during the assembly of the compressor [in London UK in the 1920's?]

What is the actual weight of each of your scale flywheels?........ might be interesting to spin each wheel [individually]  in the machines bushes with a variable speed source [drill?] and bring the wheels up to the nominal 100?? RPM & see what happens

Derek

Hi Derek,


Each flywheel is 4 pounds, 7.5 inch diameter. Real engine has two 20 foot diameter by 16 inch wide flywheels! Quite a bit of weight total!  Fortunately they won't get anywhere near that fast, these pump engines ran at 12 to 20 rpm. The pistons are 1, 2, and 3 inch diameter, roughly (have to look up the actual sizes) with a little over a 2 inch stroke. Real LP cylinder is 96 inch. Given proper valving, should be able to run it nice and slow, like my MEM Corliss twin model. With no balance weights on the cranks, they were definitely not meant for high speed. I can't imagine the pressures it would have made at high speed!


 

[derekwarner]

oops ............sorry I had the speed out x 10 fold  .......  no real need for HS balance ............ Derek

[crueby]

oops ............sorry I had the speed out x 10 fold  .......  no real need for HS balance ............ Derek

As long as we can keep the shop elves off the throttle...   

[crueby]

Lots of little bits done today. The lay shaft gear was drilled/tapped to screw it to the flywheel hub, and also got some pins made to keep the bearing halves from spinning. I drilled/tapped the caps for 2-56 brass screws, which were run in and clipped off. Matching holes in the top bearing halves were drilled(drilled at same time, then the bearings counterbored to the OD of the screws).

Then did the same thing for the lower halves, but since the base wont fit under the mill (by a long ways!) I first drilled 2-56 tap holes in the lower bearing halves. Then clamped them in place as shown in the next picture - the top halves are in place, and the caps run in but offset by one bolt hole to expose the hole in the bearing. There is a ruler laid between the bearing halves so as the nuts were snugged up it held the bearing down and level. The flange on the end of the bearing kept it aligned side to side. Then used the tap drill held in a hand power drill to drill the matching hole into the base. That was then tapped, and the hole in the bearing counterdrilled to fit over the screw.

Also drilled/tapped for screws through the flanges on the taper locks to hold them firmly in the flywheel hubs, and milled some slots in the crankshaft next to the flywheels to wedge the flywheels onto the tapers with. Have not made the wedges yet, that is next. Also also drilled/reamed the end cranks/crankshaft for thier taper pins, which will be assembled later after the rest of the bits are on the crankshaft. Whole lotta details to keep track of so I dont miss something!

[cnr6400]

 

[crueby]

The crankshaft bearings are ready for lapping. The shaft spins okay but is a little tight, some Timesavers powder and oil should free it up.

Also got a start on the lay shaft drive gearbox. Started with two pieces of 1/2" thick bar stock, milled a recess down the sides and drilled to bolt them together. The recesses will get joined up on the rotary table to make the case round. There will be a boss on the top cover to take the bearing for the driven shaft that goes up to the lay shaft.

The open side of the box goes over the bevel gear and next to the flywheel.

[ddmckee54]

Any idea how many pounds of brass and bronze swarf you and the elves have generated so far on this project?

[Dave Otto]

Pretty impressive looking with the flywheels in place!

Dave

[crueby]

Any idea how many pounds of brass and bronze swarf you and the elves have generated so far on this project?

Flywheels shed 3.2 pounds of bronze each, engine beds and frames maybe One or two total, the cutouts on the beds are in the offcut bin for future use. The pumps maybe another pound. Still a fraction of the total model, its going to be a two person mover.

[crueby]

Pretty impressive looking with the flywheels in place!

Dave

Thanks Dave, its nice to see moving parts finally!

[Roger B]

That's some fine work on those flywheels     

[Kim]

It does look great with the flywheels!  Starting to look like a real engine now    

Kim

[crueby]

Thanks guys!!

More work on the gear case this afternoon, set it up on the rotary table on the mill to shape the outside and drill the holes to match the guide made when I drilled the holes in the engine bed rail. Lots of nibbling away - the shop goat is stuffed!   

I couldn't go all the way through all the way around due to the jaws of the chuck, so then flipped the part over and held from the inside of the case in the 3-jaw to trim the rest of the outside flanges.

The angled block at the top is where the shaft and bearing for the drive shaft will come out. I am going to leave the rest of the shaping of that till later - I know the angle of the shaft from the plans (23.7 degrees) but I want to wait till the lay shaft and the brackets up at that level are made to check and see how close it comes, and adjust the angle if needed.

So in the meantime I'll do some sanding on the gear case and get it painted, and install the lower half on the engine bed. The top half can be removed with two screws for the rest of the work, even after the crankshaft is installed. On the original engine this case was made in one piece without the two bolt flanges, I think this is a reasonable change to avoid having to dismantle the upper half of the model to get at the case. This morning I did some filing and sanding on the flywheel spokes to smooth out the casting parting line.

Close to finishing up the crankshaft assembly - left to do:  install the gear case bottom half, lap the bearings, paint the flywheels, cut the shaft where it crosses the center crank webs, install the end cranks, install the crankshaft bearing caps. Long list but most are quick items. I have the bar stock for the catwalk brackets stress relieved (session in the oven a few days ago on a cool evening so it didn't heat up the house too much on hot days) and ready to go.

[cnr6400]

 

[crueby]