Author Topic: Little and large - building 2 vertical steam engines.  (Read 29074 times)

Online Jasonb

  • Full Member
  • *****
  • Posts: 9463
  • Surrey, UK
Re: Little and large - building 2 vertical steam engines.
« Reply #105 on: May 21, 2018, 03:43:44 PM »
Peter, what is the cast length of the valve chest as if that won't clean upto 2 1/4" its going to look a bit odd though there are ways around it.

Also watch your glands :o the new drawing has them with different hole ctrs and larger bore which would probably mean having to machine the smaller boss off of the cylinder casting to get back to the larger area one.

Bet you are wishing you made it from solid now :LittleDevil:

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1365
  • North Yorks - UK.
    • My Youtube channel
Re: Little and large - building 2 vertical steam engines.
« Reply #106 on: May 21, 2018, 04:26:02 PM »
At the moment the cylinder length is 56.64mm and the rough casting of the chest is about 56.15mm, admittedly I'll need to take a fine cut to the chest but the difference is small. If need be I'll mill a fine cut off either end of the cylinder.



The covers are cast no 94 and 95 which presumably is a Stuart part no ?



I wanted to make the end covers today but to be honest I'm a bit stuck and need to think it through. The top cap hasn't any spare material to hold onto for turning, it's not the end of the world but it's the first time I've made a cylinder from a casting and I'd really like to do a decent job.








Online Jasonb

  • Full Member
  • *****
  • Posts: 9463
  • Surrey, UK
Re: Little and large - building 2 vertical steam engines.
« Reply #107 on: May 21, 2018, 04:34:05 PM »
Do you have soft jaws?


Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1365
  • North Yorks - UK.
    • My Youtube channel
Re: Little and large - building 2 vertical steam engines.
« Reply #108 on: May 21, 2018, 04:44:13 PM »
I don't have soft jaws, how did you turn the outer diameter ?

I kinda thought about rough centring on the rotary table then drilling the 6 mounting holes to attach it to a temporary fixture in the lathe or even cutting the outer edge on the RT  ?

You are right about making from scratch, if I made it from barstock I'd be posting a video of it running on the hot stuff by now  ;)

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 15293
  • Hampshire, england.
Re: Little and large - building 2 vertical steam engines.
« Reply #109 on: May 21, 2018, 05:30:16 PM »
Use a pot chuck Peter.

You are right about making from scratch, if I made it from barstock I'd be posting a video of it running on the hot stuff by now  ;)

I'll let my supplier know not to provide you with any more castings then  ::)

Jo
Enjoyment is more important than achievement.

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1365
  • North Yorks - UK.
    • My Youtube channel
Re: Little and large - building 2 vertical steam engines.
« Reply #110 on: May 21, 2018, 05:37:18 PM »

I'll let my supplier know not to provide you with any more castings then  ::)

Jo

On a serious note, I'm happy with the quality of the castings. It was a bit tongue in cheek when I said I could cut from stock quicker  ;)

Online Jasonb

  • Full Member
  • *****
  • Posts: 9463
  • Surrey, UK
Re: Little and large - building 2 vertical steam engines.
« Reply #111 on: May 21, 2018, 06:43:12 PM »
I don't have soft jaws, how did you turn the outer diameter ?

Well that's the joy of starting with barstock you have got a dirty great bit of bar to hold onto :LittleDevil: Turn OD and the spigot then saw off and do the other side.



There are other ways to hold if you don't have soft jaws, 5C is one option on the spigot that is whats being used here to do the drilling



Or if your 3 jaw does not have a silly great chamfer on all the corners you can again hold by the spigot



Another option would be to face off a scrap of say 1" stock and set aside then hold by the casting by its outside in your 3-jaw to face back the spigot and mating flange face. Then with it still in the chuck superglue on your scrap of metal and let it set. Then gently skim the OD of the scrap true which will give you a decent size chucking spigot for gentle turning of the OD and outside face


Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1365
  • North Yorks - UK.
    • My Youtube channel
Re: Little and large - building 2 vertical steam engines.
« Reply #112 on: May 21, 2018, 09:29:46 PM »
Thanks Jason, you'd think makers of castings would add an bit of extra material for chucking purposes  :headscratch:

Online Jasonb

  • Full Member
  • *****
  • Posts: 9463
  • Surrey, UK
Re: Little and large - building 2 vertical steam engines.
« Reply #113 on: May 22, 2018, 06:46:37 AM »
Quite a few of them do.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 15293
  • Hampshire, england.
Re: Little and large - building 2 vertical steam engines.
« Reply #114 on: May 22, 2018, 07:47:59 AM »
Even Stuarts do, but it is normally only 2mm or so, plenty enough to machine the bottom of the flange. Yes as JBWelder says small diameter covers are often as not easier to turn from bar stock but where is the challenge in that :shrug:

And you still have to turn them over and hold them by the flange for the final machining. I think I mentioned pot chucks  ::)

I like the challenge of using castings, each has unique learning opportunities which is all part of the fun  :pinkelephant:

Jo
Enjoyment is more important than achievement.

Offline Chipswitheverything

  • Full Member
  • ****
  • Posts: 556
Re: Little and large - building 2 vertical steam engines.
« Reply #115 on: May 22, 2018, 09:40:35 AM »
Agree that it would have made a lot of sense to cast a short holding spigot, probably on the outer face.
   Not quite sure what Jo refers to as a "pot chuck".      I quite often make use of a suitable size block of MDF ( "Medite"), or a hardwood offcut held in the four-jaw, to machine awkward slices such as a cylinder cover. Does generally require a finished OD to be established first, though, and a reasonably flat back face on the workpiece.
  Just turn a slightly undersize recess in situ and tap the component into the recess.   Often helps if you remember to drill an axial hole through the MDF first, so that you can knock the item out of the holder when you're done!   Dave

Offline john mills

  • Full Member
  • ****
  • Posts: 417
Re: Little and large - building 2 vertical steam engines.
« Reply #116 on: May 22, 2018, 10:13:30 AM »
I don't mind using castings .holding spigots  still have to be cut of and the part finished.i have done these by holding by the cylinder spigot in the three jaw chuck  but also by machining a recess in a scrap piece of material
steel or alloy ,a push fit not tight held with a live centre on a entered pad is enough to finish the od.
the next series of operations that are often the challenge and have to be thought of at the start.Getting location and holding can be difficult to finish if its a casting or bar stock.working from bar can be ok but just different problems to be thought about . 

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 15293
  • Hampshire, england.
Re: Little and large - building 2 vertical steam engines.
« Reply #117 on: May 22, 2018, 10:13:48 AM »
   Not quite sure what Jo refers to as a "pot chuck".

:headscratch: a selection of my Pot chucks... these have a wide slot in the side for machining ball handles. Basically they are a piece of steel turned up into a top hat that is used in a three jaw chuck. Think of them like collets or soft jaws but without all the expense :paranoia:

Jo
Enjoyment is more important than achievement.

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1365
  • North Yorks - UK.
    • My Youtube channel
Re: Little and large - building 2 vertical steam engines.
« Reply #118 on: May 22, 2018, 05:11:02 PM »
Thanks for the suggestions guys and gals  :)

I had a think about how to turn the top cover overnight and came up with this idea.

First job was to face off the bottom (inner) side, there was a domed recess on this side but I bored this out to create a shallow flat bottomed hole and turned the cylinder locating spigot



With couple of bits of scrap I made a raised spigot and a centre drilled disc.



A drop of Loctite 638 secures the cover to the spigot and the drilled disc adds a bit of support



The bond was more secure than I expected so I was able to turn the top face without the centre support after turning the outer rim.



Next job is to drill for the 4ba fixing holes, I try to avoid the turny table if I can but in this case it is going to give the most accurate result. A fairly crude arrangement with a rule in my milling vice ensures the port face is squarely postioned.





Halfway and it's looking ok  :)



A bit more twiddling the handles and I arrive at this





I'll use proper studs later but for now bolts give me an idea of how it's shaping up.



Peter.




Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Little and large - building 2 vertical steam engines.
« Reply #119 on: May 22, 2018, 06:00:34 PM »
Excellent!




 :popcorn:

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal