Author Topic: Stuart Major Beam Engine  (Read 62009 times)

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #420 on: April 23, 2021, 06:23:57 PM »
The Boiler Feed Pump, one of the last few components for me to make.

Feed Pump by Andy, on Flickr

Feed Pump Parts by Andy, on Flickr

Feed pump rod & plunger by Andy, on Flickr

I was forewarned by Alan 'Steamhead' reply 49 way back in February 2016:

"If you look at the pump drawing (item 90) you will see the top dimension is 7/16 X 40  It should be 7/16 X 26.  Not a huge problem but it does have one scratching ones head at first".

"...when you come to do the pump.   
When at it's highest point I found the piston rod (84) was out of its guide in the main pump body, so effectively there would be no packing gland.  To fix, I made sure that the bottom plug (89) was no more than the 0.125"  spec.,  then made the piston 3" rather than the 2 29/32" spec.  The top stuffing gland is 1/2" spec.depth into the body, best to reduce this to 0.4375".(and also the gland by 1/16").  If the piston bottoms out then you might need take take a smidgeon of the bottom of it.    (If,  like me, you did the assembly with the stuffing gland in situ , then put the piston in,you would not notice there was anything wrong)".   

The pump body was held in a three jaw chuck and on a faceplate for machining.

S Major 1520 by Andy, on Flickr

Milling the top of the plunger.

S Major 1524 by Andy, on Flickr

I have made the plunger slightly longer to give me some flexibility with the distance between centres of the pump rod which will have to be calculated to suit my engine given Alan's experience.

Machining completed.

S Major 1530 by Andy, on Flickr

S Major 1531 by Andy, on Flickr

I used two 5/16" diameter stainless steel balls for the valves and graphited yarn for packing the gland. The pump worked very well  when I tested it this afternoon now I'll have to work out how to make connections to the pump which are beneath the bedplate and there's a bit of 1/4" copper pipe bending to do as well for the pump outlet.

The pump is to be fastened to the bedplate with three 6BA bolts, I haven't drilled the bedplate yet, the engine will have to be  dismantled for that. The engine is substantially complete and turns over very freely without any slack bearings, I havent fitted any gaskets or used any sealant so far but it makes encouraging wheezing sounds so I hope everything stays like that when I put it back together after painting.

Andy
« Last Edit: April 25, 2021, 08:17:08 PM by Chipmaster »

Offline simplyloco

  • Full Member
  • ****
  • Posts: 106
Re: Stuart Major Beam Engine
« Reply #421 on: April 24, 2021, 12:10:15 PM »
Hi Andy, and thanks for the dimension advice. Mine came with a part machined pump which I have yet to look at. Given the standard of the rest of of the supplied bits then I might just have to make a new one!
I'm spitting blood at the moment as the little stirrup I made for the governor has disappeared from the face of the earth!
Regards
John

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #422 on: April 24, 2021, 08:40:16 PM »
Hello John, as expected being cast iron my pump rusted overnight and pumped some mucky water at first when I tried it out today. I think a brass or gunmetal body would be preferable should you need to fabricate a replacement.

How frustrating to lose a part of the governor that probably took a while to make.

Cheers
Andy

Offline scc

  • Full Member
  • ****
  • Posts: 1002
  • Lancashire, UK
Re: Stuart Major Beam Engine
« Reply #423 on: April 24, 2021, 09:13:38 PM »
Spring has sprung.....grass has ris.....I wonder where the stirrup is :Lol:      Terry

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14423
  • Hampshire, england.
Re: Stuart Major Beam Engine
« Reply #424 on: April 25, 2021, 04:23:04 PM »
On the clack valve on your pump Andy, the top is circular but impossible to turn on the lathe. How did you do it?

Jo
Enjoyment is more important than achievement.

Online Jasonb

  • Full Member
  • *****
  • Posts: 8152
  • Surrey, UK
Re: Stuart Major Beam Engine
« Reply #425 on: April 25, 2021, 04:31:46 PM »
Jo, if you click on the image it will open in Flickr, then click the full screen icon and all will be revealed when you can see it's not a turned finish

Following along this one quietly and not so quietly John's. Does seem a bit odd that they should do the pimp in iron rather than bronze or GM, maybe they don't expect many to use it.

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #426 on: April 25, 2021, 07:33:07 PM »
Hello Jo,
the flat of the iron casting above the delivery valve was machined on the lathe as the main pump body was held in a three jaw chuck. However, the circular rim would have needed a special tool to be made so that part of the casting was cleaned up by filing.

Good to know youíre looking in, you too Jason.

Andy

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14423
  • Hampshire, england.
Re: Stuart Major Beam Engine
« Reply #427 on: April 25, 2021, 08:18:50 PM »
the flat of the iron casting above the delivery valve was machined on the lathe as the main pump body was held in a three jaw chuck. However, the circular rim would have needed a special tool to be made so that part of the casting was cleaned up by filing.

Thanks Andy,

That's what I suspected but you may have had a clever trick up your sleeve so always worth checking  ;)

Jo
Enjoyment is more important than achievement.

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #428 on: April 25, 2021, 09:34:47 PM »
I have just noticed that Jason was using Inspector Clouseau speak when he referred to ..."the pimp in iron" [reply 425] :lolb:

"Not now Kato"

Andy

Offline ettingtonliam

  • Full Member
  • ****
  • Posts: 79
Re: Stuart Major Beam Engine
« Reply #429 on: April 26, 2021, 05:16:35 PM »
It does seem odd that the feed pump is body is cast iron, when Stuart's standard practice for other engines going back many years, is to use gunmetal.
Cast iron for this one isn't a recent change, its shown as such in catalogues back as far as 1995/96 at least. It wouldn't be a difficult change just to make it gunmetal, the same pattern would do, the different shrinkage in such a small casting would be negligible, and I doubt the material cost difference would be much, not compared to the moulding cost anyway.
One to take up with the Stuart chaps at the next exhibition (this year do you think?), they always seem ready to talk sensibly about their products.

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #430 on: April 27, 2021, 10:01:41 AM »
Yes if Stuart are at the Midland Model Engineering show (14/10 - 17/10/21) Iíll ask them.

Meanwhile Iíll see if I have bronze that could be used to fabricate a pump.

Andy

Offline Chipmaster

  • Full Member
  • ****
  • Posts: 864
Re: Stuart Major Beam Engine
« Reply #431 on: June 06, 2021, 10:09:10 PM »
Working on my Stuart Major has been sidelined by other model engineering projects and boiler tests recently. However, after several hours work I completed the pump rod yesterday.

 Pump Rod by Andy, on Flickr

I used a length of 5/8" diameter steel which was sufficient to form the eye at the top of the rod. The two flats were milled on the 'eye end' down to a thickness of 1/4" and the other end was milled to 5/16" square. The milled ends were generous lengths to facilitate holding the rod for filing later on.

Ready for the pivots to be drilled at each end.



Machining the 5/8" bar down to abot 1/4" diameter in preparation for machining the fish bellied profile. 

[url=https://flic.kr/p/2m3Q4y5]
S Major 1541 by Andy, on Flickr

Machining the rod between centres using the lathe's taper turning attachment to form the fish bellied profile. The rod had to be supported by a fixed steady because it was easily deflected by the cutting tool as the section being fish bellied was about 6.1/2" long
 and only 1/4" diameter.

S Major 1546 by Andy, on Flickr

I milled the 1/8" slot in the lower end then filed both ends to shape using filing buttons. A thin wall bronze bush was made and fitted in the top end then the rod was ready to fit to the engine.

 

[url=https://flic.kr/p/2m3Q4x3]



I think there are very few parts remaining to be made but I haven't fitted any gaskets or sealant, that will be done as the engine is painted and re-assembled.

[url=https://flic.kr/p/2m3Q4wg]
S Major 1555 by Andy, on Flickr

Andy

Offline gary.a.ayres

  • Full Member
  • ****
  • Posts: 1246
  • British Isles & sometimes France
Re: Stuart Major Beam Engine
« Reply #432 on: June 06, 2021, 10:21:00 PM »
Looking amazing!

 :ThumbsUp:

Online Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 5091
  • Portland, Oregon, USA
Re: Stuart Major Beam Engine
« Reply #433 on: June 06, 2021, 10:54:17 PM »
Andy, the pump rod looks great!  As does the whole engine.  Won't be long now!
Kim

Offline simplyloco

  • Full Member
  • ****
  • Posts: 106
Re: Stuart Major Beam Engine
« Reply #434 on: June 17, 2021, 05:40:22 PM »
Great progress Andy, good to see you back 'on it'.
John