http://commons.wikimedia.org/wiki/File:GullBrehat2.jpg

Seagull Engine Construction Diary

Making a 10cc twin 4-stroke to the E T Westbury design

Cooling System

I am intending a passive convection cooling system with an open topped tank piped to the cylinders. I want to achieve neat pipework with swept Y joints, and two-bolt flanges throughout.

2014-07-24 - Making sample flanges

As a break from fettling the cylinders today, I turned a couple of discs for sample water flanges, to help decide on the right thickness to make them. I made one about 0.078″ thick and the other 0.086″. This involved making a narrowed facing tool to clear a step in the soft chuck jaws, so that I could face them to thickness. (1 hour)

2014-08-04 - Making a sacrificial milling plate

After drilling the flange blanks I started work on an aluminium plate to hold the flanges for profile milling. (2¼ hours)

2014-08-05 - Profiling a flange

With the plate drilled and tapped, and the central hole reamed, I set up the the plate and the thicker blank on the small rotary table. In cutting the sides I managed to get a jump in the table position and milled too much off one side, and probably did the same again milling the angle flanks. (1½ hours)

2014-08-07 - Finishing the flanges

I achieved a better result with the thinner (564″) flange by turning it 180° on the jig and machining from the side side to ensure both sides were identical. This is tedious because of the small screws but works well, it came out with a very small allowance for finishing.

Next, I made a pair of 316″ filing buttons for the bolting log radii. Using the buttons on the flanges showed that the flanks were not milled to a very accurate angle, but they are good enough for evaluation.

Using a bit of pipe, bent in the newly made pipe bender, I did a trial assembly with dummy studs and nuts. I think the thinner flange looks about right.

2014-08-08 - Silver Soldering

I tried silver soldering one of the flanges. I will clearly need a jig for this as the parts cannot be guaranteed to stay put by themselves, especially as the flux dries. Soldering from the back if possible should help to ensure a neat solder fillet on the visible side. Cleaning up after soldering will best be done in the jig too, as the least holding pressure on the tube soon flattens it.

2015-06-06 – Turning flanges

Today I made 13 bronze discs for water pipe flanges. I parted them off, then turned both sides using soft jaws in the chuck.(2 hours)