Rider-Ericsson 1/4 scale 2nd Time Around

[Bobsmodels]

Hi
I have been away for a bit working on another commitment for a delivery to names for Ministeam  You can see it at:

http://www.homemodelenginemachinist.com/f23/1-8-scale-galloway-build-17073/index6.html

Now I am back at the Rider other than getting stuff ready for NAMES, the next installment is the Base Casting

Base Casting

Next up was to work on the Base Casting.   I mounted it up in  the 12’ lathe as the 4 jaw had steps that allowed me to have sufficient  clearance to machine off  the bottom flat.  I like using the lathe for large surfaces like this.  The finished  bottom is shown in  the photo.   I then moved the  base over to the  Bridgeport Mill.   I clamped the base on two parallels.  I wanted it up a bit  for clearance when I bored out the cylinder  hole.   I used an end mill to clean up the top to the drawing dimensions.    The hole was centered  under the mill spindle using a co-ax centering indicator.   I used a boring head and it did not take more than a few light passes to get a nice fit with the cylinder.   Now that the base is centered the bolt holes were  center drilled, drilled and tapped for 6-32 threads.    The bolt hole pattern and subsequent mounting of the Displacer cylinder is one of my departures from the original drawings.  I am using the 6-32 bolts to provide the studs for the Displacer cylinder mounting.   In my model there is just the one set of  8 holes.   Later I will give the dimensions on the bolt length which will be about  1.3 under the head, depending on the sum of the gasket , Displacer Ring , Cylinder flange, and Base thickness’s.   A PDF is attached with my Base drawing, total time in the base  was 6.5 hours

Bob

[Bobsmodels]

Bolt Hole’ s in Cylinder

The bolt pattern is the new one I came up with that allowed the use of one set of bolts.  I attached the bolt pattern to the last post.   I clamped the cylinder to the milling table and used my co-ax indicator to center it under the spindle.  Holes were all drilled using the new pattern.  Took two hours.

[Bobsmodels]

Legs

Now I machined the legs.  I spent time filing the bottom of the legs to get the angle and surface flat.  I liked Bill’s approach to machining the legs.  I mounted mine directly to the milling table.   I started machining taking .010 off at a clip.  On one pass the cutter grabbed the casting.  The flex that high up was too much for the setup with the .010 cuts.  I made two changes— took only .005 off on each pass as Bill suggested, and I added another C-clamp.  Proceeded along with no problems after that—and another lesson learned!   Another minor departure from the prints.  When looking at the original it is clear the legs had pads not one complete surface on top.  The Base also had pads on the bottom but there is not enough material on the base to cut pads.  I thought making the pads on the legs would give enough of an “original” look.  I took .050 off in the slot.  The slot width is 1.3”.   These cuts need to be very small ie .005 as the cut is going in the weaker direction of the setup.  This took  three and half  hours.

Bob

[Bobsmodels]

Leg Mounting

I mounted the legs to the Base with some clamps and used round tube as clamp covers so as not to damage the casting.  The whole base and legs were now clamped to the milling table.  The hole positions had been spotted on the base before mounting.  Once mounted each hole was center drilled, clearance hole drilled to base depth, tap drill to depth, and then hole tapped.  This was all done for each hole.  The base was then turned over and clamped to the table.  A slot was milled for the final leg mounting bolt.  It was then drilled and tapped as above.   This took 2 and 3/4 hours.  Last picture shows all mounted.
 
Bob

[b.lindsey]

Nice work on the legs Bob. I bet you were glad to get that operation done...I remember I was!!  You are so right, things get a little wobbly that high up off the milling table. I like the personal touches you are adding to yours also. The "family" shot of the legs, base and cylinder have it looking like an engine already...exciting stuff!!!

Bill

[Bobsmodels]

Bill

Yes those legs were fun, but probably the best way to get them all square so to speak.  I am trying to catch a bit with my posts.  I am getting ready to head out to NAMES on thursday, hope to see lots of new stuff.

Bob

[Bobsmodels]

Flywheel Bracket

I am making another  modification to the design based on input mentioned earlier.  I am using a ball bearing instead of the needle bearings.  Doing this for a number of reasons.   Reduced friction and I want to make the fitting up of the crank closer to the original which used keys to hold the flywheel and crank in position.   I am using a shielded ball bearing so I can soak all the grease out and use oil.  The bearing has an OD of .875 and an ID of .375 and is form from McMaster Carr.   This will facilitate the need for making a crankshaft with new dimensions  presented later.   The  setup for machining the  casting  is  just as Bill did except I mounted it directly on the milling table.   This took a long time, 6 hours.
Bob

[b.lindsey]

You are moving right along Bob. I did use the needle bearings and have had no problem with them, Since the ID of them is open its easy to use oil to lubricate them as needed. I am curious as to how the ball bearings will work out for you.  Take a break, pack, and enjoy the NAMES show. Take lots of pictures for us!!

Bill

[Ian S C]

The oil lubed bearings should have lower drag tha the needle rollers, and friction is the main killer of these motors if you are looking for that last little bit of power.  Great motor.
                                           Ian S C

[Bobsmodels]

Additional Cylinder work

First the mounting surfaces need to be machined relative to the centerline of the cylinder.  I used the base as Bill did to square everything but again set everything up on the mill table.  I needed to hold the cylinder in place but did not want to press down from the outside as I worried that would distort the bored surfaces.  As you can see I gripped the outer part of the cylinder from the inside.  This put direct force on the wall and the vee block.  The pictures show taking the ledge off and machining the flywheel bracket mounting surface.  While the casting was in this position the water hole was tapped for 1/4 MTP.  The drawing calls out a 5/16 MTP, but I decided to use 1/4, no special reason and if I do not think it looks OK it is easy enough to change it out.  The Dimension for placing this is rather a close fit the flywheel.  It appeared that it did not mater how far out it was on that ledge.  I used .700 from the center line rather than the .750 which gave me an extra .050.  Again I laid things out and the extra space seemed to not be an issue, not much of a change.  The setup and work took 3.5 hours.

Bob

[Bobsmodels]

Ian

I am actually at the fitting up of all the links stage, just a bit behind in posting pictures.  The movement is very smooth, after a lot of time  carefully removing little binds here and there.

Bob

[Bobsmodels]

Cylinder Hole Drilling

The Cylinder has all kinds of  holes and surfaces so  I attacked those next.  The trickiest part was laying out the holes for the Flywheel bracket.  It needs to be set up to account for  the  offset of the linkages.  Once these are spotted  the rest of the hole drilling is just alignment with the center axis of the cylinder.    I do all the layout lines on my surface plate.   The first  photos show the flywheel bracket holes drilled and tapped.   I then rotated the cylinder 180 degrees and drilled and tapped the holes for the water pump.  I made a change here because my casting mold seemed shifted a bit.  There was not much meat on one side so I moved the holes in from the center line on that side from the  .670 to .630 , and noted it on the pump drawing.  The pump bracket will need the same bolt pattern.  Again I layed out the Beam support bracket holes on the surface plate.  Next I I set the everything up on the mill and located the center of cylinder with the co-ax indicator and used that to locate the holes for the Beam support.  I know this is double work using both the layout lines from the surface plate and finding the same holes using the center of the cylinder but it was a method of crosschecking the locations.  I use my DRO to drill and tap all these holes, I will also use the same setup when drilling the holes in Beam bracket so everything will be centered.  I prefer this method rather than trying to set the beam bracket in place and match drill.  Either will work just my preference.   To finish up the cylinder work took 4 hours.

Bob

[Bobsmodels]

All

I am packed up and heading off to NAMES, I am bringing the model, not done yet, but to show under constructions.  Please stop by. 

Bob

[b.lindsey]

Thanks for the nice update Bob,  its looking great too.  Enjoy your trip and weekend at NAMES

Bill

[Bobsmodels]

Hi

Had a real nice time at NAMES, saw many folks I had not seen in a year or so.  The Rider display drew comments and I picked up more suggestions on do's. don'ts and maybe's.  I will pass along some here.   One was to use an oil in the cylinder that will not burn and create a carbon cover on the bottom heating surface of the displacer cylinder - reccomendations were silicone oil (used in air guns), or Marvel Mystery Oil.   Another was to use 6061 AL for the piston rather than the casting -ease of machining.  Rather than the teflon ring to seal the piston use graphite packing string - less friction.  Someone had experimented with a graphite piston and it did not work out - I do not remember why.  One suggestion on the burner was to keep it small.  Too much heat just goes up the sides of the displacer piston and heats the base, thus transferring heat where it is not wanted. I had intended on using a 2" burner similar to that used by Bill.  The suggestion was to cut it back to 1" or 1.25".  The gas jet orifices  suggestion was a #80 (.013) and then dimple it so the drill would not go back in.  This is consistant with other suggestions of using .010 hole.  Originally I had planned on shrinking the casting on the cylinder sleeve.  I had already abandon that approach and intended on using an epoxy.  When asking others who had built this and there were four folks around me they strongly suggested using Loctite so you could remove the cylinder if - it started to rust up (not going to be a problem for me since I am using Stainless), it developed a leak, or you just needed to pull the sleeve.  My favorite loctite for this application would be 640.  That seemed to be the concensus of those asked.  640 is a slow setting (30 min) high temp that can handle tight fits ie push or press.   One other suggestion on bearings was to use ball bearings on the main shaft, the displacer yoke piviot point, and the piviot for the walking beam.

I am presenting this info for you to consider when building your engine, I find the more collective knowledge you have the easier it is to decide how you wish to proceed.

That is about all I remember, if I think of other ideas I will share them with you.

Bob