Stuart Major Beam Engine

[simplyloco]

SNIP
  Don't know if John, who is chewing over the prospective work on his Major, happens to have caught up with the forum write up that I did on my engine?, ( albeit still awaiting the finishing stages even now )  - my pics and write up are in my posts starting in March 2016.    Dave

Hi Dave
Who's Beam Engine? Chips with everything or Chipmaster?
I'm confused...
John

[Chipswitheverything]

John, my engine write up is on my own, Chipswitheverything forum posts.  Engine as per photo, but has been dismantled for a long time and still in the stage of rubbed down priming coats, and will need a proper base and plinth made too. Disappointed that it is not by now a finished engine, but circumstances have made a long break from the workshop incumbent.   Dave

[simplyloco]

Hi Dave, and thanks for that. I'll stay in touch.
Regards
John

[Alyn Foundry]

Dave, your engine is stunning.

The patina or " special " coating that's developed gives it the perfect look in my opinion.

Each to their own I suppose.... 

Cheers Graham.

[Chipmaster]

To tidy up the eccentric strap I milled the lugs and boss for the lubricator down to the same depth as the ring,




Then used a dividing head to rotate the edge of the strap under an end mill,





Drilled and threaded the hole for the lubricator then gave the job a polish,







Andy

[derekwarner]

As with all of the build parts...very tidy indeed Andy  ......

1. will you keep the 5BA round head slotted screws for the eccentric strap?, or go to a hex head bolts?......
2. do you wait, then drill and ream for the 5/64"tapered pin with the rod installed?

Just not a fan  of slotted head screws

Derek

[Chipswitheverything]

That looks nice Andy.  NB that the Stuart length dimension for the fish bellied eccentric rod is completely wrong!!, best to work it out from an eventual lash up from the engine itself as I did.
  Thanks for kind comment Graham, the mostly assembled engine did look quite interesting in the bare metal, but there is always that niggle that one hasn't really contended with finishing it.  There was a glorious cup winning Major Beam model some years ago at the Sandown exhibition, finished in mid green, which definitely made me feel that painting had to be contended with.  Though as I have used green for my Stuart No 1, I thought I'd have a change and try a deep red for the beam engine, with the baseplate black.  Dave

[Chipmaster]

Thanks for the feedback Derek.

Answering your questions,

1. I could do this ,


or this 



No, I reckon this will do 





The slotted head brass screws were a temporary measure.

2. I intend to drill and ream for the 5/64"tapered pin with the rod installed.

Mind you I haven't got on with small 1/16" taper pin reamers in steel recently. A cheap one didn't seem to be doing anything then broke in the hole so I bought an expensive version and that didn't seem to be up to much either, hardly any cutting going on unlike my selection of larger taper pin reamers. Perhaps I was just unlucky. I can see a dose of Loctite 638 being used to supplement the taper pin.

Cheers
Andy

[Chipmaster]

The eccentric was machined from a short length of cast iron bar, end machined flat then marked out for  7/32" off centre, offset in a four jaw chuck and bored out to 3/4" to fit on the crankshaft.

Eccentric sheave by Andy, on Flickr

S Major 1109 by Andy, on Flickr

I made the hub wider than the drawing thinking that an accessible grub screw in here might be convenient for initial setting of the timing later on, saves having to remove the eccentric strap to reach the 2BA screw hidden inside the eccentric that holds it in position - the 2BA grub screw can be tightened when I'm happy with the settings. There appears to be enough vacant space on the crankshaft beneath the governor for a wider hub.

S Major 1113 by Andy, on Flickr

Job held in a three jaw chuck to machine the eccentic using a parting tool.

S Major 1114 by Andy, on Flickr

S Major 1116 by Andy, on Flickr

To separate the eccentric I used the parting tool to go part way then finished off with a hacksaw just because I was in a cautious mood.

Finishing the reverse side of the eccentric.

S Major 1119 by Andy, on Flickr

Strap fitted to the eccentric,

S Major 1123 by Andy, on Flickr

Shown on a spare piece of 3/4" bar,

S Major 1121 by Andy, on Flickr

Andy

[derekwarner]

Andy.....yes those HH bolts look better ......with respect to the rod.....what material do you plan?.....AISI 304 machines relatively well....Silver Steel can be problematic....in the big picture, the loading on the rod will be low...would you consider hardened Brass bar?

After a lifetime of using or directing the use of ROCOL synthetic cutting/machining products, I recently complained to a steam colleague in my breaking an M2 Taper tap in a 1.5 diameter tapping hole size in an unknown grade of Stainless whilst using ROCOL tapping paste

His advice was try Rapid Tap......an American product which I understand contains animal fats .........I have since used this when M2 tapping without issue

The bronze in the eccentric strap may be as hard/tough as Grade 304 material........gentle hand rotation + a good cutting agent/fluid for the 5/64" taper reamer should be fine

[I shudder when hearing of crank shaft webs being joined to the journals by C-Lok pins  .......]

Derek

[Chipmaster]

Hello Derek,
the fish bellied eccentric rod would probably be made from EN1A but if AISI 304 is available I'll give it a try. However, it will be a while before I need to make the eccentric rod because of the drawings it is said,
"..... the Stuart length dimension for the fish bellied eccentric rod is completely wrong!!"

I will take heed of the warning and as Dave 'Chipswitheverything' suggests, "work it out from an eventual lash up from the engine itself." I'm just starting work on the cylinder end of the valve train in particular the bronze valve shaft bearings.

My cutting compound of choice has always been Trefolex, I like its smell and I have a large tin of it to use up. Recently I was given a bottle of CT-90 and have been satisfied with the results.



Regarding crank shaft webs being joined to the journals by C-Lok pins, I don't know what a C-Lok pin is, I'm a self taught amateur. The closest I could get with Google was "C-lok is a simple diverless subsea structural connector".

Andy

[Jasonb]

Derek your hole sounds a bit tight, for metric I usually go by diameter less pitch so 2 - 0.4 = 1.6mm tapping size.

I also use CCT-90 as unlike the thicker Trefolex it does not retain swarf in the bottom of blind holes

Andy I'll let you off not using fitted bolts with "D" shaped heads and a flat machined into the strap to stop them rotating

[Chipmaster]

Oooh Jason you're picky, I'll just have to make do with a spanner to stop the bolt rotating when I tighten my nuts up.

CT-90 also available in aerosols - which sounds good and to make it more exciting they call it 'Action Can'

 

Andy

[Jasonb]

Don't fancy trying that top left illustration, could be the last you see of your finger let alone the plastic tube

[Chipswitheverything]

....while Andy is remaking the fitted bolts with their D shaped heads, just a reminder that the fitted shanks of the bolts ought properly to be relieved over a longish portion of their plain length with three tiny flutes, so that the cross sectional area is equal to the core diameter of the bottom of the threaded portion, this so as to reduce the chance of fracture at the thread root after many repetitions of stretching with the reversing motion. ( Stretching is not then concentrated so much just at the weakest area ).    I'm not prepared to say whether or not I did this on the bolts fitted to my own engine....!!   ( I tend to think of D shaped heads as later practice, maybe marine use, would they ever have appeared on a beam engine of this mid 19th C date ? )   Dave