Hi Guys
Thanks for checking in Simon, I appreciate it.
I have been trying to get an update posted recently and extra time has been pretty hard to come by. I have made a little progress on the oilers; and have some pictures to share. Not the greatest photos but hopefully ok.
I designed and printed a couple sets of soft jaws that would cover all the different operations on the oiler castings.
First up the large hole where the sight glass retainers fit, needed to tapped. I dropped a 7/32” end mill in the cored hole to true it up then followed with a #2 reamer and then tapped 1/4-32 all the way through.
The cored holes were slightly oval and the end mill helped get things round enough that I could them ream them.
Brass sleeves were turned and pressed into the threaded holes; a stepped mandrill was turned and used to press the sleeves and insure they were centered from side to side in the bore. After pressing, a little drop of wicking Loctite was added on each side to help seal everything up.
Here are the castings after installing the sleeves. The sleeves kept me from having to thread up to the shoulder.
Here is a cutaway of my CAD model showing the next challenge. A port needs to added between the sight glass area and the back side of the stop valve. The port will be drilled from the bottom of the stop valve boss up into the sight glass area. Then a brass plug pressed in fill the hole.
The soft jaws hold the casting at the proper angle for drilling. The hole was spotted with a 1/16” end mill to make a small flat; then center drilled and drilled.
Roland sent me a few of these brass rivets that were just the right size to plug the hole drilled with a #53 drill bit. The rivets were annealed to hopefully keep the drill from wondering when the stop valve hole was drilled.
I had calculated the exact length needed to pretty much fill the hole and after drilling would leave the short passage open. I wanted to get as much material in the port as possible to keep the drill from wondering as it passed through. I decided to leave the rivets long so there was something to hang on to. A small line was cut in the lathe so I would know how far to insert the plug; also the oxides were polished off at this time.
Here are the installed plugs. I was able to grab the rivet in the vise and wiggle the casting on to it; making sure to stop when the line contacted the casting. Loctite was also added to the plug before pressing it into place.
A pair of side cutters were used to nip off the excess plug material.
Then carefully belt sanded close to the casting. Using a magnifier and needle files the plugs were filed to the original contour of the castings.
Time to set some tools for the next two operations.
Again the soft jaws were used to hold the casting at the proper angle so the stop valve boss was square to the world. The center of the feature was indicated in and the tools set to the top of the part.
I was having so much fun I forgot to take any pictures. The boss was center drilled, then drilled with two different diameters; one that goes all the way to the vertical center of the casting and the larger diameter that get tapped and also forms the seat for the valve. By looking at the CAD cutaway you can see that the depth of the seat needs to be held pretty close as there is not much wiggle room there.
The boss was also chamfered and the threads milled on at this time. I had the CNC stop centered over the hole and the last step was to put a spring loaded center in the spindle and tap the 3-48 threads for the stop valve.
The next operation was to finish the pipe threads and lower port where the oil comes out. The first operation was to drive around the boss with an end mill to square up the small radius left from the mold. Then the chamfer was milled.
The port was spotted and drilled. Again the drill depth needed to be correct and required a little tweaking of the code to get it spot on. I actually did both operations on a couple parts (stop valve boss and lower boss) to make sure the holes were going to come out correctly. I was quite happy when they came out just like my CAD model.
The next step was to mill the threads; I decided to go with ¼-32 straight threads as my CAM program won’t generate tapered threads. I fiddled with the thread depth until I got a nice fit on some of the PM Research cast fittings.
This is where I’m at so far on the oilers. I’m pleased with how things are progressing. Next I need to start thinking about the features of the upper section of the castings.
Thanks for checking in.
Dave