Chris's Holly Pumping Engine Build

[crueby]

Some more information on that square box/bolt thingy on the pump housings - I was digging through the Holly blueprints some more, and found this gem:

In several places they refer to the bolts on those box shapes around the flanges as 'Stay Bolts' - a term I am used to seeing on boiler plans. Given the location, horizontally above and below an opening and that they are only present on pressurized chambers, not there on intake/suction chambers, this lends more credence to the theory that it is there for strength purposes, helping reinforce the opening against the outward pressure. The bolts through them would give compression to that area.
Unless any of the commercial-vessel experts have another explanation?

[crueby]

And a little more on the bearing blocks - got the sides all milled down like in the previous post, so next step is to round over the bottoms of the protrusions on the sides. Easiest way to do that was to pull the blocks off the engine beds and mount them on the rotary table with an arbor and mill that edge. Hard to see in the photo, but the bottom edge was taken back in an arc to the level of the panels at the end, which are at the level of the side rails. Both sides of each bearing block, except for the one face with the gear housing mount, will be taken down this way.

To get the cap to stay on, some little sections of tube were cut to act as spacers on the studs, the threaded ends were not long enough to hold the cap on without the rest of the engine bed being there.

[cnr6400]

Hi Chris, re stay bolts - that note indicates to me too that the bolts are helping the casting withstand internal pressures, just like stay bolts in a boiler do.

The bearing machining looks great! 

[crueby]

Hi Chris, re stay bolts - that note indicates to me too that the bolts are helping the casting withstand internal pressures, just like stay bolts in a boiler do.

The bearing machining looks great! 

Great!  I asked a couple friends about it too, one passed it along to a structure engineer he knows, he said same thing. Calling that one explained!   

[derekwarner]

Explained?.......not sure 

The issue I could not understand was how did they ensure these bolts were adequately tightened?.......or became loose due to gross cyclic or harmonic vibration?.....so this at first appears to be resolved with the following explanation 'courtesy Google'

Locomotive Boilers and Engines. Stay-Bolts. The universal method of staying flat surfaces of the fire-box at the sides and front is by the use of stay-bolts. These stay-bolts are screwed through the two sheets of the fire-box and are riveted over on both ends.

Would be interesting if these 'riveting procedures instructions appear in any assembly Drawings

Fully explained?....... ... the stay bolts in the boiler explanation as above relates for the securing two [2] opposing 'separated surfaces'  .....in this pipe spool application the bolts only provide tension to the diameter of the washer for the 3" diameter threaded stud, within the 'solid section' of the cast lug 


Derek

[crueby]

Hi Derek,


Unfortunately no assembly instructions included in the drawings for this or any other parts, so no way to be sure. Some  places they mention machining a surface or reaming a hole for a taper pin, but thats it. Probably lots of procedures that those crews knew to do, but no ISO9000 stuff back then! The fact that two different companies did the same thing on similar parts indicates it was not done on one designer's whim.


At least it's a reasonable explanation for the feature on he casting, it had to withstand pressure pulses every couple seconds, hard to say how high the pressure was, certainly a lot less than a boiler, but repeated.


Chris

[derekwarner]

Absolutely.....lets get me back to watching [again] .... & keep the mouth closed apart from a

Our engineering forefathers were certainly not Mugs ...our current Crew are so smart, they still cannot figure how their fathers did things without computers & CNC & faith in a supreme power

Derek

[MJM460]

Hi Chris, I have not seen a detail like that in my forty years in the oil industry, but for me, that “stay bolt” note settles which of the two likely purposes others have proposed was intended.  However it may well have been used for both purposes.  Of course, the oil industry does not use cast fittings for pressure piping, but when those engines were built, available material and fabrication techniques were different.

Normally, a side branch is reinforced by the “area replacement” method, which results in the reinforcing pads normally seen around pressure vessel nozzles, or integral reinforcement on forged tee fittings.

However in this case, there is a very large diameter branch in a very short fitting, making it difficult to fit in sufficient reinforcement.  Those bolts would add considerably to the strength of the fitting to withstand the circumferential stresses in the straight section.  The longitudinal stresses are only half the circumferential stress for any given pressure, so longitudinal bolts would not be needed.  Particularly with cast fittings, those steel bolts in tension would be considerably stronger than the cast iron, so by pre-compressing the iron they would help ensure the integrity of the fitting in the absence of sufficient other reinforcing.  Note that this is a very different application than the boiler staybolts as Derek has described for flat plates.

But I am also hoping that Propforward will come in here, as he is using far more sophisticated tools than were ever available to me for these calculations.

Regarding the pressure involved, I did notice your little hint a while back that I could explain water hammer in my thermodynamics thread.  I have sorted out sufficient maths, but am still thinking about how to present it so it is actually understandable for anyone interested.  I have the book by an expert, but while chapter one is very clear, I am sure the author dropped the papers on the floor before publishing and there seems to be three chapters missing between chapter one and two.  Certainly a leap too far for me.  The maths to get started is simple enough, to get as far as pulsation levels  and forces, but how to present it without a pile of unintelligible graphs is a challenge.  So stay tuned, it is coming

MJM460

[crueby]

Great MJM, thanks!

[crueby]

Got the rest of the bearing block sides acred at the bottom yesterday, the one with the mounting pad for the gearbox gets a much simpler side panel, just one large semmicircle.

that is drilled for the gearbox mounting screws

While the rotary table was set up for that set of holes, I put in an offcut piece of roundbar and drilled it to match the pattern. This will be used as a drill alignment guide when the gearbox housing is made later. Carefully marked to what it is so I have a chance of finding it later on.


So here is where the parts stand at the moment

Next shaping will be on the upper corners of the bearing blocks where they go across the top of the side rails.

They were rounded off using an end mill and taken flush to the tops of the side rails.

That finishes the shaping of the bearing blocks and the engine beds

Getting close to done on them - got the holes drilled/tapped in the sides of the engine beds for the brackets to hold the catwalk floor at that level. The catwalk goes around the entire engine, in the center between the beds the floor is a step higher to give better access to the bearings. Lots of 1-72 holes to thread, glad I have the tapping guide now.


Final steps before assembling things again is to sand down the toolmarks

and get things painted....  I need to test if I'll be able to get between the engine beds to install the floor brackets there, or if they need to be made first. Assembly is going to be fiddly, the vertical braces down to the pump chambers need to go in at the same time so the order of things will need to be worked out to ensure I can get at all the screws.

[Kim]

Wow, Chris!  That is a lot of nice work.  I'll bet you're happy to move on to something besides bearing blocks now! 

Kim

[crueby]

Wow, Chris!  That is a lot of nice work.  I'll bet you're happy to move on to something besides bearing blocks now! 

Kim

Yeah, to bearings!!   

[Admiral_dk]

Still enjoying your Journey and fine work        

While the rotary table was set up for that set of holes, I put in an offcut piece of roundbar and drilled it to match the pattern. This will be used as a drill alignment guide when the gearbox housing is made later. Carefully marked to what it is so I have a chance of finding it later on.

Very good idea - but I do not see any reference showing what side it belongs to .... please don't do like I do from time to time and "mirror" the reference 

Per

[crueby]

Still enjoying your Journey and fine work        

While the rotary table was set up for that set of holes, I put in an offcut piece of roundbar and drilled it to match the pattern. This will be used as a drill alignment guide when the gearbox housing is made later. Carefully marked to what it is so I have a chance of finding it later on.

Very good idea - but I do not see any reference showing what side it belongs to .... please don't do like I do from time to time and "mirror" the reference 

Per

The holes are evenly spaced around the rim, so the side doesn't matter - though the side with the writing on it is the side facing away from the engine bed. The main thing I wanted to capture was the actual distance from the center of the shaft, that is hard to measure on these shapes in any case, and when the engine beds are assembled on the model getting in to measure that would be even harder. So, used a disc from the scrap bin to capture it!
 

[crueby]

Just went down and grabbed the engine beds from my paint booth (a cardboard lined bench) - wow, what a difference in the appearance with a single coat on!