1/4 Scale Rider-Ericsson Pumping Engine

[vcutajar]

Bill

I have been meaning to ask you this question since you started this build.

Your aluminium castings, like my Kiwi castings a covered with a greyish patina or paint. I suspect this is normal for aluminium castings, but how do you intend to remove it?

Vince

 

[b.lindsey]

After that the flywheel bracked was attached with four 6-32 hex cap screws as shown in the first two photos below. Its pretty tich quarterseven for a slim hex driver but tight enough for the moment. I am sure it will have to come apart a few more times as things progress. Prior to doing this work I drilled the three cross holes in the beam though that set up isn't shown. The last two pictures for today are with everything done thus far assembled as they will be in the final model. Thanks for checking in!!

 

[b.lindsey]

Vince, for the most part these castings weren't too bad for rough places though there were a few like the beam and some of the corners of the firebox. Then there are the parting lines where there is some flash as well and this is true for most of the cast pieces. Mainly a file or belt sander was used to at least blend these in. One of the nice things to me about castings is that they look like castings as opposed to smoothly machined bar stock. This model will be painted in the end also which will help hide some of the surface variation, but even so much of it will remain. I still have the full size cast iron block casting here by my desk from the Briggs engine and if you look closely, aside from the machined surfaces its pretty rough too!! Casting can vary a lot of course and i suppose if a fellow was picky enough or wanted a smoother more finished appearance, you could apply a filler like "bondo" or similar and then sand it down smooth before painting. I don't anticipate doing that with this one.

Bill

 

[vcutajar]

Thanks Bill for the info.

Vince

 

[lazylathe]

Turning out beautifully Bill!!!

Very interested to see how you do the piston for this one!

Andrew

 

[b.lindsey]

Yeah....me too Andrew. I think most of that I will do on the Sherline equipment...same for the power piston center too, but want to get the cylinder sleeve finished first in order to fit the piston to it.

Bill

 

[b.lindsey]

Andrew...you had said you have the same casting kit earlier on page one. If you have a chance can I ask a favor? Could you measure the smallest diameter piece of pipe that was supplied (the one for the displacer piston). The prints call for 1.75" OD with .060" wall. What I got was 1.875" OD instead. It still fits well within the hot cap pipe just with less clearance. I am thinking this was a material change that just never made it to the prints but would appreciate any confirmation of that if possible. As i had said my prints are still dated 1977 and show no revisions at all.

Bill

 

[modelman1838]

Bill
If I were you I would be more than happy to go with the 1.875 o/d tube as the 1.750 o/d called up seems to be much too much clearance for a hot air engine in a 2.000 bore. When I built my 1.500 bore scratch built one from the book " S&S you can build", not having any tube supplied I bored out a piece of 1.50 o/d stainless steel tube to 1.450 bore and made up a copper displacer with .030 clearance only all round. and it works just fine.
Hugh.

 

[lazylathe]

Hi Bill,

I will check tonight and let you know.
Not home from work yet...

I will also see what year my plans are dated.
From what i remember they were pretty old as well.

Will let you know soon!

Andrew

 

[b.lindsey]

Hugh,
Thanks for that information too!! As is typical in all of the sterlings I have done, there is minimal clearance as you say so I am thinking this isn't an issue and may even be beneficial as you point out. Since this is still an active model from Mr. Myers who supplies the castings, it would seem that an update in the plans is in order and muchly needed. Mine still show a sheet metal firebox as well as I think i mentioned earlier. Again....thanks so much for the input!!

Bill

 

[lazylathe]

Hi Bill.

I have the plans dated 5-1-77.
The smallest diameter pipe i have with my kit is 1.74 O.D, it varies along it's length with 1.75 being
it's greatest in the middle somewhere.
The wall thickness is 0.066.

My plans call for 1.75 OD and 0.06 wall thickness.

I am pretty sure we have the same kits and the same plans! ;D

Hope this helps!

Andrew

 

[b.lindsey]

Nothing very exciting today but I did get the stainless steel cylinder sleeve machined to length and the 3 step diameters turnedwhere they will mate with the cylinder casting. Now i have to finish boring out the casting so it will slip in. The last picture shows the stock bore which measures round and already has a nice smooth bore. Just a little honing and it should be good to go.

 

[b.lindsey]

The hot cap tubing only had to have the ends faced and brought to length. This one picture shows it next to the cylinder sleeve. I also started on the displacer tube but didn't get it finished. Both the hopt cap and displacer piston will need thin plugs silver soldered into the bottom of them. The hot cap also need a mounting flange soldered near its top and the displacer will also need a thicker plug in the top where the actuator rod will attach.

 

[b.lindsey]

Andrew, sorry I missed your post last night...thanks so much for checking. The plan dates are the same for sure but your tubing size is as specified on the plans, mine is 1.875 OD with apprx .060 wall. As Hugh mentioned this may be just fine and I think I will proceed with the tubing supplied, keeping in mind that I did that in case it doesn't work out for some reason. I do think I will contact Mr. Myers though just to see if this was a mistake or if it really doesn't make any difference. Thanks again!!!

Bill

 

[b.lindsey]

Okay, here's the deal as per Mr. Myers himself who responded to my email in a matter of minutes I hasten to add !! There was a change in tubing size from 1.75 OD to 1.875 OD in order to reduce the clearance and therefore air volume. Aparently this has worked well as reported by other builders so we'll see how it works out on this one.

Nothing like a GOOD customer service experience to get your day off to a good start...so thanks to Mr. Myers for that!!!

Bill

 

[arnoldb]

You're really moving along at a good clip on this one Bill! Great job so far :bow:

Kind regards, Arnold

 

[lazylathe]

I will wait for you to finish then i will decide if i need a bigger pipe!!! ;D

To me there is not so much of a difference in sizes although it may affect the running considerably!
A lot have been built to the old sizes and have worked well so far.

I will have to put a note in the plans so i do not forget about it...

Andrew

 

[b.lindsey]

Today I pretty well got the displacer piston finished...machined the tube to length at work yesterday, cut a round sheet metal plug for the bottom of it and a slich of round aluminum for the top. This morning I silver soldered the plug into the bottom of the tube and machined the top end aluminum plug. Rather than attaching the acutator rod with two set screws at 90 degrees I am going to thread it into the top with a 10-32 thread. In picture 1 below I had cut a piece of scrap tubing just short of the tube length by the thickness of the plug and the .030" recess shown on the plans. This was just to siupport the plug evenly during soldering.Photo 2 shows it all fluxed up and photo 3 the results after soldering and cleaning it up. Not the best soldering I have done but its in there and no leaks which is what matters.

 

[b.lindsey]

These three photos show the straightforward machining of the top end to the displacer piston and how it looks fitted to the tube. In all liklihood, this will be loctited in at final assembly.

 

[b.lindsey]

Just a few more pictures from Friday afternoon through this morning. First is the initial machining of the displace yoke to get the mounting point widths to spec. The second one shows the hot cap tube, displacer tube, and cylinder liner in their relative positions on the cross sectional print. And finally this morning I made the displacer rod shown in the top of the displacer piston assembly. Hopefully more later today...

I did get a start on the power piston over the weekend as well but will hold pictures of that until more is done on it. That is being done at home on the Sherline equipment.