Stuart Major Beam Engine

[Chipmaster]

Some work on the cylinder top cover.

The drawing,

Cylinder top cover by Andy, on Flickr

Cleaning up the underside and edge of the casting.

Cylinder head by Andy, on Flickr

Forming the register that fits inside the cylinder and drilling for the piston rod.

Cylinder top cover by Andy, on Flickr

Starting to clean up the top of the cylinder cover.

Cylinder top cover by Andy, on Flickr

A small blowhole 

A blowhole in the cylinder top cover casting. by Andy, on Flickr

I polished the casting with emery paper to see whether I could achieve a decent finish but was called in to dinner so that was the end for today.

Cylinder top cover by Andy, on Flickr

Andy

[Jo]

A small blowhole 

 

What's it look like this morning Andy any better? Can you live with it or is it a case of make/get another one?

Jo

[Chipmaster]

Morning Jo,

I reckon I can live with it, I'll try to machine a bit more off the casting, after all the dimensions of that ridge aren't important. I could position the cover so that bit is out of sight or fill and paint it although I do fancy polishing it.
What do you think looks better?

I'll do some more engineering this afternoon 
Here are some pictures of ST Major top cylinder covers.

Stuart Major Cylinder Top Cover 1 by Andy, on Flickr

Stuart Major Cylinder Top Cover 2 by Andy, on Flickr

Stuart Major Cylinder Top Cover 3 by Andy, on Flickr

Stuart Major Cylinder Top Cover 4 by Andy, on Flickr

Stuart Major Cylinder Top Cover 6 by Andy, on Flickr

Stuart Major Cylinder Top Cover 7 by Andy, on Flickr

Stuart Major Cylinder Top Cover 8 by Andy, on Flickr

[Alyn Foundry]

Good morning Andy.

From your photographs I'd say more an " inclusion " rather than a " blowhole " you can see the mark in the unmachined casting prior to the turning operation.

These can be caused by bits of sand being dislodged during the pattern removal or the pour.

Ultimately, the choice is yours as to finish. We all know what happens to untreated Iron when subjected  to the environment!   

Cheers Graham.

[Chipmaster]

Hi Graham, I see what you mean. I hadn’t noticed the mark in the unmachined casting, well spotted.
I do admire polished metal surfaces but I’m not allowed to keep my engines in the warm house.
 I have to keep an eye on them in the garage.
The flywheel rims on my Alyn Foundry RLE were like polished chrome. However, I was shocked to find them rusty when I took it out of its closed wooden box recently. Fortunately I had caught it in the nick of time and after a hour the rims were shining again. It had only been put away for two or three months and the water jacket was bone dry.
Reckon you have far higher humidity where you live.
Andy

[Jasonb]

It is an area I do tend to paint along with the middle of the other cover if it is exposed eg a horizontal cylinder but then again I'm not really one for a lot of spit and polish.

Just the top nut bearing surface and the 1/16" step would have been machined on the full size engines casting leaving all the bead and area inside with a cast surface until you got to the top of the spigot which again would have been faced.

[Chipmaster]

Finished machining the cylinder top cover this afternoon using a few form tools that were to hand.

WP_20190615_16_29_49_Pro by Andy, on Flickr

Opened out the hole for the piston rod gland (from 11/32" drilled from the other side yesterday) to 1/2" to a depth of 9/16"

WP_20190615_16_51_37_Pro by Andy, on Flickr

Cover sitting on top of the cylinder.

WP_20190615_17_02_34_Pro by Andy, on Flickr

Andy

[Chipswitheverything]

That's looking nice Andy, the casting has turned to a decent finish.  It'll be a while before you need to make a final decision on the painting.  I'm going to have to paint the inner part of mine, though, as there are a few small casting blemishes in that area.  Similarly, as I may have said in my own earlier write up, I have had to paint the main tapered column as the iron had a speckled micro porosity that I could not polish out at all.  But though the polished column looks rather good, as on Mr H A Taylor's beam engine, I doubt that the real engine would have had other than a cast, filled and painted column.   Dave

[Alyn Foundry]

Hi Graham,
Reckon you have far higher humidity where you live.
Andy

Yep....

About eight feet higher than normal Andy.

[Chipmaster]

Hi Dave,
yes the top cover casting was fine. The column casting of my kit seems pretty good and could probably be buffed up and look very smart but as Graham points out it might be difficult to maintain the finish, especially where he lives!

Today a little progress - drilled the cylinder top cover and cylinder + tapped for six 4BA studs.

WP_20190616_18_26_53_Pro (2) by Andy, on Flickr

Then made a lot of swarf turning down  a piece of cast iron bar to 1.1/8" to make the piston rod gland

WP_20190618_16_24_19_Pro by Andy, on Flickr


Piston rod gland - copied from the plans
Piston Rod Gland by Andy, on Flickr

I carried out all of the machining without removing the cast iron bar from my three jaw chuck so the bore and outside are concentric. Most of the metal was removed by a parting off tool.

WP_20190618_16_41_37_Pro by Andy, on Flickr

WP_20190618_20_43_49_Pro by Andy, on Flickr

WP_20190618_20_43_58_Pro by Andy, on Flickr

Job almost done,

WP_20190618_20_41_38_Pro by Andy, on Flickr

A flat is supposed to be milled on one side of the gland to provide clearance for the cylinder lubricator that will fit in a 3/16 x 40 tpi hole that can be seen in the bottom of the recess on the right hand side of the picture. A couple of bronze bushes are also required to fit inside the gland and guide the piston rod.

Andy

[crueby]

The top cover is looking great!


 

[jeff l]

Very nice work!

[Chipmaster]

Thanks Jeff, I'll soon be making the parallel motion spacers using your form tool as I progress up from the cylinder.

Andy

[Chipmaster]

A little more work on the piston rod gland required two gunmetal bushes, the Piston Gland Bush (15) that fits inside the gland and the Packing Gland Bush (16) that fits in the cylinder top cover. The funnel shape of the packing gland bush will squeeze the packing material onto the piston rod when the gland is pulled down by three 6BA nuts. I machined the bushes - turned, bored and parted off from a bronze bar that stayed in the lathe chuck throughout to ensure they were concentric.

Copied from the plans,
Piston rod bushes2 by Andy, on Flickr

WP_20190620_20_46_26_Pro by Andy, on Flickr

Packing gland fitted in the cylinder top cover,

WP_20190620_20_47_22_Pro by Andy, on Flickr

Viewed from below,
WP_20190620_20_48_15_Pro by Andy, on Flickr

Piston Gland Bush pressed into the gland.

WP_20190620_20_48_45_Pro by Andy, on Flickr

All put together

WP_20190620_15_58_35_Pro by Andy, on Flickr

Miraculously the reamed bores of the bushes have lined up, the piston rod (attached to the piston in the cylinder without rings) moves without binding.

The next item will be the piston rod crosshead which looks challenging, for me anyway..... the square central bit, tapered bore also a tapered wedge = potential to mess up many hours of work with silly mistakes
I have zoomed in on several pictures of completed ST Majors on the Internet and noted some variations in the way the piston rod is retained in the crosshead.

Piston rod crosshead 1 by Andy, on Flickr

Andy 

[Chipswitheverything]

Hi Andy, bushes all looking good in situ  ( sounds more like landscape gardening...! )   The crosshead is a nice but fiddly thing to make.
   Just thinking about it, I might suggest leaving it for now until you have the radius rods and the motion link split bearings to take actual measurements of bores and widths from:    as it could be easier to make the turned areas, dia. and lengths,  on the crosshead, suit your other components than to make the other bits conform to the crosshead. I found it quite helpful to be able to measure what I had , and tweak the dwg. of the crosshead a few thou here and there.  Depends on your liking for working to pre arranged tolerances, perhaps...     Dave