Modeler's Corner

Gade Buildup Continues


| January 2005



CylinderBeforeMachining.jpg

Cylinder before machining.

Hello again, everyone. As you might remember, last issue I told you about breaking the crankshaft for the Gade. Let me tell you, crow leaves a sour taste in my mouth, and I was really embarrassed telling Roland of my error. As I said last issue, the break was neither his fault nor the fault of the casting; it was just human error on my part.

Well, the new crank is now ready. I have cut it to the proper length and I have cut the key ways in both sides of it. I cut the key ways a little differently than called for, as a 3/32-inch end mill is small and other options are available, if you look around. I did have to get a 3/32-inch woodruff key cutter, but it was well worth the extra time spent doing it this way.

Key Way Cut

I locked the crank into place, set the key cutter in the mill head and let it take 0.015-inch cuts. Three passes 2 inches long had me where I wanted to be - 0.0469-inch deep - and the keys where nice and straight. Here again I had another question for Roland: The keys are 90 degrees from the throw rather than the usual 180 degrees - why? I spoke with Roland to see if this was correct, or if it might be because of some design flaw, and he assured me that this was how it was done at the factory, and Gade did this to all their engines. Gade must have had a reason for doing this, but neither Roland nor I know why. Was Gade the only manufacturer to cut their key ways this way?

Cylinder Work

I have now finished off the cylinder jug; it is bored to 0.8750-inch, a 7/8-inch hole, and is reamed and honed, I always drill a new bore undersized by about 1/32-inch, and then finish it with a reamer. The rear port is drilled and tapped; I changed this from the 5/16-40 thread called for to a 5/16-32 because that's what I had for a tap and I only needed to order a die. The 5/16-32 thread is the one I use most when model building or when making propane demand valves (I will cover this one day soon) because it is the thread size used on tire valve stems. I also drilled a small pilot hole for the oiler.

I have cut the jug to length and machined the face flat. I left as much material on the rear face plate as possible for mounting to the base, and as I get done with the head I will drill the top of the jug to match it. My trusty little die grinder did get some good use, as it was time consuming removing all the flash from the fins. But it was enjoyable to sit, relax and finish this part of the jug, knowing it is now ready for primer and a coat of silver paint.

I flattened the base on my table sander and then set it into the milling machine to square everything off of it; the mounting side of the cylinder jug is flat and square and I have set the proper height.