Chris's Holly Pumping Engine Build

[cnr6400]

Hi Chris and Sid, That sure looks like the working end of a barring engine to me,  in the Boston pics. The shown worm and worm gear with its' low helix angle would not back drive.

Some barring engines on large steam engines moved the shaft and pinion into and out of mesh with the flywheel with a swinging lever / block pivoting around the engine crankshaft or secondary shaft, with the engine fixed to the frame.

The one in the pics looks like it maybe slid the whole subframe and engine / gears assy in and out to mesh and unmesh the pinion with the flywheel.

Great to see the pics and diagrams of the Boston engines. 

[sid pileski]

Wish I had time to take better pictures!

Maybe when Chris gets back there, he can solve the mystery definitively!!!

Any other members up for the challenge?

Sid

[crueby]

This morning finished up cutting the openings in the center of the engine bed plates. Same kind of procedure as doing the arcs at the ends, just straight cuts. Couple of passes to get down to the depth of the end mill, then flipped the plate over to do the other side and connect up the slots.


First one set on top of the pump frames to have a look at the shapes, quite a difference!

Next up is to attach blocks that will be shaped to the arched lower supports under the crankshaft. I think I will attach these with some screws hidden under the pump chamber support beams, in the center of the arches, along with some loctite for good measure.

Once the screw holes are drilled/tapped, will need to set up the rotary table and a tooling plate to offset the blocks to mill in the arch shape on the outside. There are flats projecting down in the center to connect to the vertical beams, and also to take the lower end nuts for the bearing blocks up above.

[cnr6400]

 

[crueby]

Productive afternoon, between read/naps out on the porch.  Got the arch blocks drilled/tapped to screw them onto the bed plates:

then made up a jig to hold them the right distance out from center on the rotary table - used one of the cut-outs from the center of the bed plates, was just the right size. Laid out and cut the box shape into the outside edge of two of the blocks - the two end ones have support flats for the vertical beams to the pumps, the other four will also have bosses for the bearing block bolts. These two are simpler, so I am starting with them to work out the procedure.

The two holes you see inside the box are where the screws are, they will be covered by the vertical beams.  Then comes the fiddly bit, machining in the arc shape without hitting the center box, and without going too far towards the narrow ends. At the ends, the shape will reverse the curve to blend in with the bottom of the plates at the ends of the beds. Those reversed arcs will have to be cut in later with the rotary table on its side. In this picture, one end has been shaped down, several passes, lowering the mill head each time, and rotating the rotab to cut in the arc. I am taking shallow nibbles to avoid putting too much force onto the fixture, just those two 4-40 screws in the center hold it in place.

[crueby]

Both ends arched on the first two of the blocks, and starting to mill out the other four parts. These four have bosses at the corners of the center plate, so a few more moves to lay it out. I'm going to mill all four like this, then start the arching cuts. Final cuts on the thin ends will have to be done after laying the rotary table out horizontally. The bosses will be rounded on the corners with a rotary tool last.

[gary.a.ayres]

Great development. Some masterful skills in evidence here.

Good job that elf wasn't sitting having lunch on a girder 900 feet above the streets of Manhattan when you cut it though!

[crueby]

Great development. Some masterful skills in evidence here.

Good job that elf wasn't sitting having lunch on a girder 900 feet above the streets of Manhattan when you cut it though!

Just had flashback to the old movies like that - Harold Lloyd, etc. !

[crueby]

Some more done on the blocks with the bosses around the flat section - started the arc work with the small end mill, back and forth between cutting the arc and taking the sides of the bosses down vertically.


then switched to the larger cutter to take the ends down close - as mentioned before, the ends will be finished up with the rotab horizontal to flare the ends to match the existing plates.

Fiddly work, taking lots of breaks between parts to keep the concentration up with all the rotary etch-a-sketching!

[crueby]

After finishing up on the middle portions of the arcs, set up the same holding fixture on the horizontal rotary table and did the ends, where they transition from the main arcs to reverse flare out again.

Here is how they look on the engine beds

And set on top of the pump frames. Looking good, next up will be to make the bearing blocks that sit on top of the engine beds.

The shop elves like them, nice spot to sit for a mid-day beer!

[Kim]

Very nice, Chris!

Are you going to solder those blocks to the main unit? Or just leave them screwed together?  I'm assuming they were all one casting in the original?

Kim

[crueby]

Very nice, Chris!

Are you going to solder those blocks to the main unit? Or just leave them screwed together?  I'm assuming they were all one casting in the original?

Kim

Hi Kim,


Yup the original is one big casting. I am going to put some loctite in the joint and screw them together, these blocks won't have any side forces on them. For the bearing blocks on top, I am going to notch the top and side faces of the beds, and make the bearing holders with a slot on the bottom to hold them in place. Those will be through bolted when the bearing caps are in place so will be strong that way. Those through bolts will go through the lower arch blocks as well. Still a few weeks to go on these engine beds!

[cnr6400]

Be sure to check all the oilways/steam ways in the engine in case Bucket Bob crumples up his beer can against his forehead and drops it in the nearest hole....... again.......

Great progress! 

[crueby]

Be sure to check all the oilways/steam ways in the engine in case Bucket Bob crumples up his beer can against his forehead and drops it in the nearest hole....... again.......

Great progress! 

Its those stupid pull-tabs from the cans that he leaves everywhere - nasty on bare feet!   

[Don1966]

Dog, Dog, Dog, I don’t know what to say but……..I…………likeeeeeeee….. 



 
Don