Author Topic: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine  (Read 4340 times)

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6767
  • Surrey, UK
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #60 on: November 13, 2019, 08:20:28 AM »
It's a bit of an unusual way to do it in the UK as generally only traction engines and road steam subjects use that convention of inches to the foot with stationary engines using fractional scales. So just like in the book most people in the UK would describe it as 1/4 scale.

Though they did list it as  3" scale not just 3" so less likely to be related to bore.


Offline Dave Otto

  • Full Member
  • *****
  • Posts: 3642
  • Boise, Idaho USA
    • Photo Bucket
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #61 on: November 13, 2019, 01:30:57 PM »
Thanks Jo

That clears it up for me. :)
I have castings for both the 2" (1/4 scale) and 3"(3/8 scale) engines. The 3" castings are from Myers and the 2" castings are old enough that they were from Norbert Keely the guy that originally did them way back. I think Clarence Myers acquired the patterns for the Rider-Ericsson and also the Essex fan from Norbert. Need to find time to work on them someday.

Dave

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #62 on: November 14, 2019, 04:25:04 PM »
Strikes me you have a lots of sets of castings Dave that need to be converted into models. Maybe I should send Surus over to check you are treating them correctly.  :pinkelephant:


A little bit more on the engine. A set of studs made for the beam Support and the bottom of the support has been shaped up. The drawings suggest that the cylinder should be shaped back to match this support  :noidea:

Jo
Enjoyment is more important than achievement.

Offline bent

  • Full Member
  • ****
  • Posts: 455
  • Wet side of Washington State, USA
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #63 on: November 14, 2019, 06:22:50 PM »
Nice progress, Jo.  :popcorn:

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #64 on: November 15, 2019, 07:24:15 PM »
Thanks Bent  :)

I am still working towards being able to bolt down that bracket.... so next I need to do the beam, which will locate the crankshaft. The beam was banana shaped  :facepalm2: Having milled some flats on the sides I found that there was a 1.3mm off set between the ends of the beam and the centre features.

The reference is the pivot so first up find the pivot's centre (checking the two ends fit reasonably on the beam) and set up to bore it. This could them be used to face the two ends, one of which is slightly further out than the other and with the banana shape the tool caught the ribbing  :Doh: Before taking down the two edges either side of the oval hole.

Next a bit of hole drilling.

Jo
Enjoyment is more important than achievement.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #65 on: November 19, 2019, 03:14:36 PM »
The beam was mounted onto a plate to enable two holes in the beam end to be reamed, the slot for the piston rod to cut, the side ribs to be milled straight and for the top and bottom ribs to be thinned.

The casting around the piston rod slot was a bit uneven so was filled to bring it up then smoothed down with a hand file and some emery.  The beam could be milled to make the ribs at the top and bottom thinner but I have already taken about 4mm off so I will leave it there for now  :) .



Thanks to Muddled Engineer for the visit today  :-*. Surus made a big fuss over him and even let him look through his casting collection   :headscratch: I think it was a ploy to see if Eric had any more casting sets that he thought Surus needed...It was found that he still needs a Stuart 6A and the 600 :pinkelephant:

Jo
Enjoyment is more important than achievement.

Offline Admiral_dk

  • Full Member
  • ****
  • Posts: 1494
  • S°ften - Denmark
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #66 on: November 19, 2019, 08:22:04 PM »
Nice progress with the beam and engine Jo  :cheers:

Still following along  :popcorn:

Offline bent

  • Full Member
  • ****
  • Posts: 455
  • Wet side of Washington State, USA
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #67 on: November 20, 2019, 05:58:05 PM »
Jo, do you use something like JB-Weld (steel-filled epoxy) for your Aluminum backfill repairs?

After doing some of the machining on my fan project, the castings "sprung" and some of the holes ended up moving.  Am debating repairing them, or using clamps to de-spring the parts before bolting them together... :noidea:

Also may want to patch/smooth some of the casting pores and pits before painting, and not sure what would hold up better under heat?

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #68 on: November 21, 2019, 02:33:30 PM »
Thank Per  :)

Hi Bent, that is standard plastic epoxy filler as used on cars. Sometimes it is worth using JB Weld if I need something that can take a lot of temperature. I have also been given a tub of epoxy metal filler which I have not opened yet. While you may think of the top of a stove as being very hot relatively it isn't I doubt it will boil water and if it is hotter your fan will quickly overheat....


The power piston centre casting was also missing  :-\ So I made it up from some brass bar. I could have used a 25.4mm diameter bar and turned it down for the main body of the centre but chose to just stick on a collar of the wider diameter to save my sparse metal stocks  :paranoia: The two bosses are for the bottom of the links and these have been made by drilling the centre of a piece of brass 4mm (just under 2BA tapping size) and then using the side of a milling cutter the diameter of the body of the piston centre to scallop out the inner curves.

The piston centre bar can now be drilled 4mm at the appropriate point for the centre of the bosses, a suitable piece of brass tube inserted: I drilled a bit of brass 2.8mm here to take a 6BA screw to hold the bosses on. Having dampened the joints and dipped the damp bit in some flux it is ready to be silver soldered together.

Once silver soldered it can have the bottom of that 25.4mm diameter turned again to make sure it is true and the 1/2" by 26TPI thread cut using a die. The last bit being to add a bronze bush in the centre with Loctite to provide the sliding surface for the displacer rod.


 :thinking: I think we are ready to attach that flywheel bracket... With all the links in place it is obvious that the flange where it mounts to the cylinder casting needs a bit taken off. Once that is done the two holes for the mounting bolts can be drilled out 3.2mm (4BA tapping) and now I need to transfer those holes onto the cylinder so I need a 3.2mm diameter centre punch to poke down the two holes to mark the centres.

Jo


Enjoyment is more important than achievement.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #69 on: November 21, 2019, 04:03:58 PM »
Having turned a point on the end of a bit of steel this has been successfully used as a transfer punch  :cartwheel: while on a roll I also did the two at the bottom of the bracket and added a countersunk screw to provide the other leg mount.

A quick family shot and then in for an evening of fondling   :mischief:

Jo
Enjoyment is more important than achievement.

Offline bent

  • Full Member
  • ****
  • Posts: 455
  • Wet side of Washington State, USA
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #70 on: November 21, 2019, 09:02:11 PM »
Nice work Jo!  :popcorn:

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #71 on: November 22, 2019, 02:04:42 PM »
Thanks Bent  :D


The next casting the displacer yoke is horrible:- nothing proved to be square or parallel  :-\ So the first step was to locate the holes and that the ones on the end of the two arms went in at the correct distance from the edge of the casting and that the other two holes were square to them  :paranoia:

With the holes in place the edges of the two arms could be taken to width. then it was time to do a lot more measuring. As I suspected the main yoke part was offset from the ends of the two arms  :facepalm: Luckily there was just enough on one side of the arms to get it back in the centre.

It is now coffee time while I contemplate how to continue with this yoke  :noidea:

Jo
Enjoyment is more important than achievement.

Offline bent

  • Full Member
  • ****
  • Posts: 455
  • Wet side of Washington State, USA
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #72 on: November 22, 2019, 06:11:14 PM »
Would've like to see that drilling setup, were all the holes made in one go?  :noidea:

Offline ChuckKey

  • Full Member
  • ****
  • Posts: 90
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #73 on: November 23, 2019, 01:17:53 AM »
With the holes in place the edges of the two arms could be taken to width. then it was time to do a lot more measuring. As I suspected the main yoke part was offset from the ends of the two arms
A decent alloy (or gunmetal) casting is unlikely to mind a bit of careful bending to correct the geometry.

(I was recently staggered by the ductility of a full-size loco cylinder drain cock after the loco struck a fallen tree. The body of the almost new gunmetal casting had been twisted 30, maybe 45 degrees relative to the mounting flange and there was no cracking evident on a cursory inspection.)

 Anyway, you seem to have got away with it this time.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12834
  • Hampshire, england.
Re: Camden 3" scale Rider-Ericsson Hot Air Pumping Engine
« Reply #74 on: November 23, 2019, 07:39:31 AM »
Sorry Bent I forgot to take a pic of holding the casting by the side of the "C" shaped bit and packing under the flat bit while drilling the holes  :-[ I drilled three holes like that offsetting the tapped hole at the end of the arm relative to the end profile of the arm, then turned it over and used coordinate drilling and checking the offset from the end of the arm to locate the second threaded arm hole. It was not fun  :ShakeHead:

With the holes in place the edges of the two arms could be taken to width. then it was time to do a lot more measuring. As I suspected the main yoke part was offset from the ends of the two arms
A decent alloy (or gunmetal) casting is unlikely to mind a bit of careful bending to correct the geometry.

I have many times adjusted a casting by a quick tweak in the vice with an encouraging implement. I did consider it on this one but on this casting one arm was actually slightly longer than the other so I am assuming the pattern was offset as well. Bending it "straight" would have meant that the short arm would have had the screw hole right on the end of the metal and needed filler to build up the profile of the missing arm  :paranoia:


I suspect I will be spending a lot more time on this casting before I am happy with what it looks like.  :noidea:

Jo
Enjoyment is more important than achievement.