Rider Ericsson Homemade Castings

[raveney]

Base
The next part cast was the baseplate. I needed to modify my larger flask by adding corners because I didn't have enough greensand. The pattern used 3/16 plastic lettering purchased from a plastic model supply site. Swept a compass across the painted surface and estimated the spacing first. Then laid it out with tweezers and finally glued in place one letter at a time with white glue. I am glad I waited until I had painted and smoothed the wood patterns as these letters don't stick up that much. I waxed and buffed to help pull the letters from the sand. The Esses are a little messy, but its legible. I always admired how other people did this on their models. It adds a lot of realism in my opinion.

I gated into the bottom surface so the tapered edge would be preserved, and placed 1/2 & 3/4 copper risers on the two thickest bodies to compensate for shrinkage. I barely had enough in the crucible (lucky). I will definitely need my larger ones for the next two parts, the Flywheel and Cylinder. There are some indications on the cylinder mounting pad that I hope are superficial.

 

[GreenTwin]

Another great looking pattern and casting !

.

 

[creast]

Base
The next part cast was the baseplate. I needed to modify my larger flask by adding corners because I didn't have enough greensand. The pattern used 3/16 plastic lettering purchased from a plastic model supply site. Swept a compass across the painted surface and estimated the spacing first. Then laid it out with tweezers and finally glued in place one letter at a time with white glue. I am glad I waited until I had painted and smoothed the wood patterns as these letters don't stick up that much. I waxed and buffed to help pull the letters from the sand. The Esses are a little messy, but its legible. I always admired how other people did this on their models. It adds a lot of realism in my opinion.

View attachment 156845

I gated into the bottom surface so the tapered edge would be preserved, and placed 1/2 & 3/4 copper risers on the two thickest bodies to compensate for shrinkage. I barely had enough in the crucible (lucky). I will definitely need my larger ones for the next two parts, the Flywheel and Cylinder. There are some indications on the cylinder mounting pad that I hope are superficial.

View attachment 156846View attachment 156847It's coming on really great.!!

 

[raveney]

thank you again for the encouragement!

Cylinder
This is a large part for my experience in sand casting. It will require my largest flask, additional sand, and a real core for the bore. I purchased 24 lb of new foundry sand. It feels much sharper and bonds better than the other sand I have.

I used it to make the core. The core pattern is just a slit piece of 1-1/2 plumbing PVC pipe. Needed to place hose clamps around the PVC to prevent spreading and increased diameter. I also reenforced the sand core with a piece of TIG wire so I could handle it. This must be the absolute limit of an unbound sand core as it cracked , but held enough to work.

The first attempt failed miserably though as molten aluminum seeped out of the bottom somehow. Very glad I had lots of dry sand underneath to catch the spill or I would have been replacing part of my paver driveway.

I couldn't really tell why this pour failed, so I tried again without doing anything different. This attempt was not 100% perfect as it appears to have had some loose sand in the casting on the bottom mounting rim. Hopefully this can be filled in with epoxy as it appears to be limited to the circumference only. It is so terribly hot, 97F with 47% humidity, during the afternoons here in central Florida right now, so I decided to call it a day. I had exhausted my propane tank anyway.

I plan to get an early start on the two legs tomorrow.

 

[raveney]

Legs

these patterns require digging out the sand to an imaginary split line. I had some practice several weeks ago, but ran out of sand so didn't make the pour. The first pour was terrible. I really think the big difference in success so far is the professional parting powder. But improper gating and venting will still ruin a cleanly released mold. I believe I connected the vent or riser below the topmost part of the casting and steam blew out the corner.

So I added one more vent and moved the risers towards the top. I also poked a few vent holes with a bit of wire. I may have started straying towards the damp side with the sand. The next two legs (left side) came out nicely and should clean up well.

 

[raveney]

Flywheel

the curved spoke pattern was a special challenge for me. I approached it by using an online flywheel simulation, clipping an image, and then printing out a paper pattern full-size.

https://rawgit.com/tinglett/MachyTools/master/FlywheelBuilder.html#spoke



I then cut a single pie shape out of 1/4 plywood using a scroll saw and sanded the inside cutout carefully. This sector pattern was then indexed around an MDF center piece and traced. The center piece was actually two thin pieces held together by painters tape.



Cut each opening roughly using the scroll saw again. Then used a flush cutting router bit to trim out the six identical shapes. But I still needed the rim widths added.

I rough cut two circle blanks again which were fastened to a wooden faceplate to taper the inner and outer diameters. Tapered dowels were cut for the hubs and glued on.

Painting the MDF raised grain several times before becoming smooth. Finally some fine abrasive pads and paste wax made them smooth enough to use.

 

[GreenTwin]

That is just some outstanding pattern work on this build !

Wow.

.

 

[creast]

I agree. Fantastic pattern work!

 

[raveney]

Thank you for the generous compliments!
I got back to the project to cast the last piece...
and it came out first try i really like how the curved spoke wheel looks, can't wait to see it spinning.

I am real glad the messy part is done, so I can clean up the sand and sawdust that seems to have gotten in every corner of my workshop.

 

[GreenTwin]

Nice !
You are on a roll.
.

 

[100model]

I purchased 24 lb of new foundry sand. It feels much sharper and bonds better than the other sand I have.

Hobby metal casting must be a lot more popular today as I was surprised that you can buy green sand in small lots. Another way to use less sand is to use blocks of wood of different sizes in the corners like you did. Great looking castings.

 

[raveney]

Cleaned off all of the flash from the parts with various files and sandpaper. Here is the resulting home made casting kit
My metal lathe is not big enough to use it to face off the base as the book suggests. I will need to surface it in the mill instead. It looks like it will be challenging to grip/fixture most all of these parts as I machine them. At 2" diameter, this will be the largest bore engine I have built so far. The flywheel matches what I did on the OTTO-LANGEN also.

 

[GreenTwin]

Those castings turned out very well.
Nice !
.

 

[raveney]

Thank you sir!

Base and legs were fairly straight forward to machine. I bored the cylinder hole in the mill because it wouldn't fit on the 9" faceplate. The legs were clamped to an angle plate with an aesthetically pleasing amount of angle on them using a picture of the real one. I made my own hex nuts to appear scale, but went one size larger than typical (5/16") for the 8-32 studs.

 

[raveney]

Boring the cylinder took nearly two days. I didn't think about how I was going to counterbore the water jacket. The book also showed the cylinder being held in a much bigger and stiffer lathe chuck than what I have. I used a 10" x 5/8" boring bar with 7" stickout and 1/4" HSS bits.

Started at 400 RPM and 0.010" depth of cut and finished at 100 RPM and 0.015" DOC. The chatter was bearable by placing two 4# lead shot scuba weights on the bar. Used compressed air to blow the chips out. Once the bore was opened up to 2", I put a plug in the end and used a center to face the ends. The counter bores were made using a different type grind because it needed to plunge and run both directions. I saw this bifurcated cutter grind in a build tip sheet for the black widow V-8 and use it whenever I need to plunge a crankshaft journal. Worked good here also.

special cutter has a kerf in the middle to reduce cutting surface



Used the mill to cut the pads on each side to dimensions in the book. I then clamped the flats to a angle plate and centered on the bore so I could make the 8 #8-32 clearance holes to mount to the baseplate. I held off on the other holes so I can make the flywheel bracket fit correctly. I think I want to assemble everything together before drilling and boring the pivot points. This should minimize friction on the linkages.

 

[Jasonb]

A tip for next time. As you were using castings the core should have been shaped to produce the water space by being a larger diameter in that area. You would then only need to machine the two smaller diameters at the end where the liner makes contact.

Although my Denny is fabricated you can see how the water space is larger so just the ends need machining

Regarding boring large overhanging parts, sometimes it can be better to skim part of the outer surface true so that a fixed steady can run against it, once dressed and painted it won't show where the surfcae was machined.

 

[raveney]

Both points well taken Jason.

I confess that I was contemplating both ideas while I was babysitting the lathe take each pass in lowest gear with lowest feed.

The core would have required making a split wooden core mold... correct?

I do have a steady, but its not big enough for the 3" diameter of this part. I almost built a larger one. Another thought was to line bore it while it was strapped on the saddle. I think the larger core would be the better of all options, based on cost and time saved. Surprised that the 5/8" budget friendly bar only chattered a little bit.

I worked on the flywheel bracket next. Seems I goofed up when positioning the pad on the wooden cylinder pattern. It is about 2 hundred low. Best solution in my opinion was to add a custom 0.213" shim plate to the base. The drawings in the book weren't dimensioned and I either scaled them or held the patterns together to match things up. I will correct by field measuring the pivot beam crank rod and the displacer rod. See below where I layed some allen drivers against the two parts I'm considering altering later. Please give me any advice if this is a bad idea.



The next step was bolt everything together on the surface plate and make the assembly level and square. Transfer to the mill table and reference the cylinder, base and spot-drill the yoke pivot point and flywheel axle. I purchased 7/8" x 3/8" ball bearings a while ago. I forgot what size they were and they weren't labeled. I then had my pal BOZO measure them, and he said 0.900". Huh, I thought... that's odd. I nailed the dimension with the boring head on one side and did a final check with the bearing. It was real loose so I measured it again. Hmm...0.875" this time. I can imagine that BOZO read the caliper wrong again, but he's a good guy otherwise.

Luckily I had two 23mm x 11 mm ball bearings which I will use instead. I was able to increase the bore to 0.906" accurately this time. The 0.433" flywheel shaft can be made from a piece of 7/16" drill rod. I'm pretty happy with the project so far. It's nice when you can improvise and save a part(s) from the scrap bin.

 

[GreenTwin]

That is an impressive casting effort !
Much respect.
.

 

[Jasonb]

Looking good

The core box would really need wto be split so you could get the core out. Though for home use you could just print a half mould and fill that with your core material to make two half cores that could be stuck together. Other options would be to make round cores and glue a short smaller dia one to each end of a larger round core.

I had to bore out my lathe steady to get it to fit that casting!

 

[creast]

Fantastic work!
I wouldn't worry too much about the 0.2" shim piece. these things happen!
You could epoxy in place and blend after. If you are painting the finished engine you would never know.
great work mate!