Month: December 2016

Inline Twin Engine Ep. 3

In today’s episode, I’ll be making the crankshaft.

This whole engine is built around the crankshaft, and it’s design. It will be a test bed for future use of this idea.

Please refer to Inline Twin Engine Ep. 1 for a CAD rendering of the crankshaft.

The individual parts are turned on the lathe first. This will be the rear, the flywheel end of the engine.

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Second side finished turned.

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The crank discs were turned next:

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What will be the front end of the engine (the accessory end):

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After all the parts are finished turned, it was over to the mill. I machined a set of soft jaws, to be able to hold the part accurately on the bearing seat. It is very important the hole for the crank pin is not only accurate in diameter, but also exactly perpendicular for everything to line up when assembling the crankshaft. Any misalignment would result in binding of the bearing.

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Two of the discs were drilled to be tapped, and two countersunk.

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The front and rear parts being finished as well:

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The different parts, ready for assembly:

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…and the assembled crankshaft:

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The crankshaft installed in the crankcase:

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To demonstrate how well it turned out, a short video:

I’m very pleased how free the crank is running. This part of the build has exceeded my expectations, and I can already envision this type of crankshaft in future engine builds.

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the projects page in the top menu.

Yogi

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Inline Twin Engine Ep. 2

The first part I’ll be making, will be the crankcase. Alongside the crankshaft, the crankcase will be essential on proofing the design of the built up crankshaft.

To better illustrate the steps in machining the parts, I’ll start with the CAD renderings of the finished parts. This will help to visualize the different setups.

The top half of the crankcase:

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…and the bottom half:

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I started with the inside of the two halves, by milling out the pockets that will make room for the connecting rods.

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Next is the outside shape. First, I milled the flange where the two halves will be screwed together. Second operation was to mill the angled relief.

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The same process was used for the top half of the case, except one side is different where it will house the cam shaft.

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The two halves stacked on top of each other, to get the first impression of how this engine will look like.

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The next step is to bore out the case for the crank and cam shafts.

The two halves are screwed together and set up vertical in the vise.

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Using a boring head, I started with the bore that will hold the camshaft.

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… and continued with the bore that will hold the crankshaft bearings.

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At this stage the crankcase was faced over, to ensure the surface is perpendicular to the bore, and the hole pattern for the cover was drilled. The operation was repeated on the other side, machining the case to its final length.

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The last operation was to drill and bore the top to finish the case.

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The finished crankcase (minus a few threads needing to be tapped  ;) )

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Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email me at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the projects page in the top menu.

Yogi

Inline Twin Engine Ep. 1

After the last couple engine builds were single cylinder engines, I felt it’s time to build a multi cylinder engine. I settled on a 2 cylinder engine of my own design.

The unique part of the design is the built up crankshaft. The inspiration for the crankshaft comes from H. Schillings, a german model engine builder. It utilizes large, thin section ball bearings to register the different parts accurately. The idea is to have easy to make parts that will assemble to a strong, true running crankshaft. If this crankshaft design proofs to be successful, I already have plans to utilize this design in future engine projects.

The goal for the engine will be to have a well running, slow idling engine. I set the compression ratio at a modest 5.5 : 1. This figure is a stab in the dark, as the compression ratio is a compromise between performance and idle characteristic of the engine. The slow idle is important to me, and I feel I can achieve what I’m looking for with the mass of the flywheel and crankshaft combined.

The engine is built up from bar stock. Throughout the design, I tried to simplify the parts as much as possible without compromising the look too much.

The engine will be liquid cooled, requiring a full set up with pump, fan and radiator.

A few dimensions to get a feel for the size; Bore 32 mm, Stroke 34 mm, Flywheel diameter 90 mm, Height to top of cylinder head 178 mm

I modeled the engine in CAD. To illustrate what the finished engine should look like, I’ll start with a few renderings:

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The built up crank shaft:

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Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email me at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the projects page in the top menu.

Yogi

Moving a Bridgeport Mill

As always, I’m looking to add tools to the shop, and recently acquired a Bridgeport Mill.

In this post, I’ll share a few pictures of how I moved the Mill to my shop.

To lower the center of gravity of the top-heavy machine, the knee was lowered all the way down and the head turned upside down. Once loaded on the trailer, it got a generous treatment with a roll of shrink-wrap. This will help keep the road dirt and grime off the machine.
A set of chains around the bottom of the column was used to secure the machine on the trailer. In addition to the chains, I used ratchet straps over the top of the machine. I made sure none of the chains and straps are putting any load on the lead screw or ways. This secured the machine very well for the trip home.

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To offload the machine off the trailer, I got help from my friend with his skid steer loader.
Bridgeport style machines can be easily lifted with the forks under the ram. First, we grabbed it from the side to get it off the trailer.

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A second setting from the front of the mill, with a couple of 4×4’s across the forks, to move the machine into the shop.

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…and the machine in its place in the shop, next to the Maho mill.

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I hope this helps some of you, who are looking into moving a Bridgeport type mill or any other machinery to your own workshop.

If you have any questions about my workshop or any of the projects, please leave a comment below, or email me at yogisworkshop(at)yahoo.com

For other projects, please check out the projects page in the top menu.

Yogi