Entablature Steam Pumping Engine

[Jasonb]

Dave, I've been looking at that governor for the last few days and something did not look right to me. Do you feel the arms are a bit on the thick side? looking back at the etching the arms look thinner than the main shaft, you seem to have them about 50% thicker.

Comming on well though.

J

 

[Rivergypsy]

Hi Jason,

You might be right there, now I look at it again. I'm not sure if I got carried away getting these modelled, and then didn't recheck.

Still thanks for pointing it out, and far better to have too much metal on than too little right now. I'd better break out the files again tonight then

Cheers
Dave

 

[Rivergypsy]

Ok, now I think I've got the feed pump drive rod, with it's gab end modelled now. The sliding keep is still to be done, but while I think it looks feasible, I'm very keen to hear anybodies opinion before I start machining

 

[Rivergypsy]

First draft of Op1

 

[kvom]

My thoughts on that rod: make in 3 pieces. Handle on the lathe, center portion 2.5D machining, long rod portion turn down the end, then bend to fit. Join by threaded rods or soldering.

 

[Rivergypsy]

Nearly there on the governor now - just the main arms to thin down, and the lifting links to fettle

 

[Rivergypsy]

I've been a bit distracted lately with going over my new Chipmaster lathe, but starting to make a bit more progress on the engine again now. I've profiled the eccentric strap halves for the feed pump on the CNC, sawn them off of the billet, and bolted them together, and now faced and finished the bored. Next job getting it up in the four jaw and turning the tail on the lower half...

 

[Rivergypsy]

Well there's been a bit more progress over the last couple of days, but never enough hours free to make a big difference

Yesterday I turned the taper on the tail of the strap, holding it between the sides of the jaws of an independant 4-jaw; a technique I've seen Antony Mount use. It gripped well enough, but was a pain to align as you have to adjust the jaws a pair at a time. Also, with a 4mm corner rounding cutter I got the side lugs profiled.

Today I got the sheave fitted inside it, but there was one small tight spot, so I gave it a few minutes running in on the lathe using WD40 as a lubricant, and it all runs a treat now. Next job will be the usual needle file, emery and then scotchbrite, to blend the rads.

Off to the valve eccentric next

 

[Rivergypsy]

Here's a bit more progress, after getting a little side-tracked starting to draw up the next engine (a big project compared to this, but should be kind of cute).

I've got the governor lower links filed and papered to shape now, which was an extremely fiddly and careful job. so for that, now it's just the arms to thin down, and the correct dowels to fit.

The feed pump eccentric is in place too, so what's currently underway is to cut and file the keeps and wedges to shape to finish assembling the con-rod. Once this is in place, then it'll let me centre the crank and get the relevant spacers in place.

The gab end for the feed pump rod is currently on the mill too, but very slow progress to cut the pocket with a 2mm end-mill...

 

[Generatorgus]

Quote: the next engine (a big project compared to this, but should be kind of cute).

Dave, A project like the Entablature would take me the rest of my life.

Good to see your back to posting the build.

GUS

 

[Rivergypsy]

Lol - Many thanks, Gus. You're doing to lovely job on your project, but it always feels like you boys build a lot faster than I do
This is the next project if all goes to plan - just starting to draw it up in SW now, but a lot of work and head scratching...

View attachment 20130515081641442.pdf

 

[Generatorgus]

HOLY COW!!!

I sure hope your going to post it.

GUS

 

[Rivergypsy]

Lmao - let me get a bit more of it drawn up to make sure it's feasible. It's a long term job, thats sure though...

 

[Rivergypsy]

Well, back in the swing of things now, I think

Here's the blanks for the feed pump gab end and actuating lever, and for the straps for the valve linkage. They're just been profiled on the cnc ready for hand finishing so far.

What i did try yesterday is to hold the tail of the gab end in order to turn the taper on the handle - bad move. It started ok, but then caught up and twisted, so after a little straightening I'll hand file the handle. It should be salvgeable though. :wall:

Last night I also finished making the wedge for the first of the lower ends of the con rod, and hopefully I'll get the second one done later today. All ready for another session of files, paper, and black fingers...

 

[Rivergypsy]

Definitely back in the swing of things now

The rod is finally finished and polished, and part way through a final fitting to the crankshaft. I've a couple of tight spots to ease out, but that'll get done at the weekend. And it lines up with the crosshead too, so that's a bonus, lol.

The straps for the valve gear have been 2nd op'd - very thin to hold though, so that was a twitchy moment...

And finally, the link for the feed pump with it's gab end is coming on nicely - the end I'm shaping by hand as it's getting quite thin now, the rod I've turned and fish-bellied from 6mm stainless, and have also got the keep roughed out, and an M1.6 threaded knob turned for it out of phosphor bronze.

Very nice to start getting some motion work in place at last!woohoo1

 

[Gedeon Spilett]

all these links look awsome, and the brass cornice with rounded edge too.
you finally succeed in deciphering the plan for the gab ends, brilliant.

Is your workbench, which is paved with wooden bricks, as seen in the pics ? classy

 

[jwcnc1911]

Rivergypsy, what CAM are you using?

 

[Rivergypsy]

HI Gedeon,

Many thanks - your help and sketches were invaluable with those links! Glad you like the brasswork too, although there's still a fair bit of filing to do there, and squaring out of the corners.

I actually took the pics on our old butchers block in the kitchen - I'm building in the house, and it's got pride of place on the dining table Only of these would make a nice workbench though - they're 6" thick and weigh a ton!

JWCNC - I'm using GibbsCAM as it's what we have at work. It's ok, but I'd prefer SolidCAM as the CAM will update automatically as the model changes, wheras with Gibbs it's more of a pain. Do you use CAM too?

Dave

 

[Rivergypsy]

All going nicely still, thankfully - the feed pump drive is now in place.

I had one issue when I fitted the rod, though. The lever that takes the drive to the shaft looked very 'blocky' against the more sculpted rod and crosshead, so i stripped it back out and filed it to a lighter, more radiussed form, and am much happier with it's appearance now. I'm not sure if George Gentry missed a little detail here, but it did stick out like a sore thumb.

One of the next pieces for the feed pump is proving a 'slight' pain in the butt at the moment. The centre lever, which takes the drive from the shaft to the links onto the pump rod has a very tricky shape to form. I've rough milled and turned it, but there are hours of filing laying ahead, as i really do want it from a single piece of metal rather than a fabrication...

Oh, and on a final note, there's a flywheel sized billet (11" x 1.5") billet of steel on it's way as a birthday present - beats more socks any day and I've also found a 4" billet for the drive wheel, which has been rough turned leaving 1mm all over, and I aim to rough the spokes later today. I'd planned on leaving the roughed parts for about a week for any stresses to come out, before finish turning and 3D milling on the spokes.

And as a downside, I also found that the 'rod fouls the crosshead guide bars, not by much and an easy fix, but I missed it on the CAD :wall:

 

[Rivergypsy]

And a little more - here's the drive pulley roughed out to within 1mm all over