Bollaero fixtures

[digiex-chris]

I recently made a new piston and liner for an RC engine to practice making the tapered cylinder fits, and it runs great! Now I think it's time to try an entire engine. I've grabbed the plans for the Bollaero 1.8, but I'm wondering what the consensus is for the best way to make the cylinder bore perpendicular to the crank bore? I've got a lathe with a milling attachment, but it's not a great attachment, I much prefer to do the highest accuracy stuff with it setup as a lathe. I've got a 4 jaw chuck, and I'm comfortable with it to bore the crank case and face the end of it, but then how do I mount it on the cylinder axis guaranteeing it's lined up right with the crank?

 

[Admiral_dk]

Go to http://modelenginenews.org/ and search "Building the Sparey 5cc Diesel".

It can be done in different ways, but here, Ron shows you how to do it with success.

 

[digiex-chris]

I see, bolted to an angle plate through the crank hole. I don't quite get how you can get the axis of the cylinder aligned with the axis of the lathe though, registering on the crank bore only gets you one of the two axises you need to align. The casting can still rotate around the crank hole until the bolt is locked down. Unless you measure the distance of the mounting lugs from the faceplate or something?

 

[mu38&Bg#]

The square stock makes it easy in a four jaw unless I'm not understanding your question. Verify the stock is square or square it yourself. Layout or center punch the two bores. Use a wiggler or the indicator method to center it. Use an indicator on the carriage to verify parallelism or perpendicularity.

Ron Chernich's methos will work as well. This will help explain how he does it. Follow the link to the Midge as well.

This isn't linked on my site yet, but this is how I bored out an existing crankcase last week. I just had to make sure the original bore was centered though.

Greg

 

[digiex-chris]

I suppose I am over-thinking it. It should be easy enough to verify my chuck jaws are as they should be. It's not like I need repeatable setups for this engine. The crank case looks to be the easiest part of it, a nice and easy part to re-make if I screw it up. Thanks!