5 Cylinder radial (winter's project)

[vcutajar]

George

Thanks for the info. That's good to know. Need to store that info for future reference.

Vince

 

[gbritnell]

This morning bright and early I made a fixture to hold the cylinders for threading. I first mounted each cylinder and turned the spigot on the head end to .75 and qualified the overall length. I wanted to have them ready to go once I set up for threading. The next picture is of my hand crank. It's a little crude looking but I would rather spend the time on the engine. I took one of my threading tools and ground most of the 30* angle away on one side, just enough to get the depth I needed and get as close to the shoulder as possible. I did make up a small necking tool (.031) to undercut the bottom of the threads. The next picture shows the threading. I used my LED light to illuminate the job and forgot to reset my camera, hence the blue tint.

 

[gbritnell]

Upon finishing the threading I made up a threaded arbor for holding the heads for further machining. The cylinders were turned and the fins cut much like the cylinders so I'm not going to repeat the picture process. The one picture show the internal threads being cut. Here again I undercut the bottom of the threads with a .031 necking tool.
The next 2 pictures show the threads in the head and on the cylinder. The 4th picture shows the 2 parts screwed together.

 

[gbritnell]

The final picture for today shows the 2 heads and cylinders screwed together and mounted on the crankcase.
George

 

[gbritnell]

Here's today's progress. I finished turning and threading the cylinders. Now the real fun begins, ports, valve seats, fins and spark plug holes. I thought I would take a couple of pictures with the cylinders all put in place. In the one photo I have a half dollar sitting next to the engine to give you an idea of the size.
George

 

[stevehuckss396]

Hello G!

Is this going to be one of those deals where you finish the head, attach the cylinder permanently, and then drill the flange at the bottom of the cylinder.

 

[gbritnell]

Exactly so Steve. Trying to locate head bolt holes in something like this is nearly impossible. With the head shouldering against the cylinder it should make a positive stop. When I get the flat at the back of the head machined (for the ports) I will use this as a stop while I tighten the cylinder. Once assembled they will go into a fixture and have the base holes drilled. If they ever have to come apart they should clock up right at the same point they came apart.
I have to layout a machining program for the combustion chambers. That will be the next step in the process.
George

 

[kustomkb]

Beautiful work George! It's a real pleasure watching your progress.

Thanks for the detailed posts.

 

[doc1955]

WOW!!!
How did I miss this build?
I'll have to go back to the start and read from the beginning.
But from here it is a beautiful looking piece of work!!!
Nice!!!!

 

[gbritnell]

Gents,
The work is resuming on the cylinder heads. The next step was to put in the combustion chambers. The chamber is hemispherical so I made up a drill rod forming tool on the lathe and then backed of the relief by hand. I left just a whisper of flat at the cutting edge so that I could knock it down with a diamond hone after hardening. The heads were put in the vise against the port face flat and a stop was clamped up so that I wouldn't have to pick up each head. The cutter was touched of to a piece of .125 stock laying on the flange, the -0- was set and then the chambers were cut.

 

[gbritnell]

With the chambers cut I pulled my big vise from the table and set up my angle table with the smaller vise. Everything was indicated square and then the table was tilted at 30*. Another stop was set up for repetition. The first part had the centerlines laid out and they were picked up with the wiggler.

 

[gbritnell]

The valve pocket machining would required another home made tool. This would consist of a pilot (.1875), a counterbore (.235 x .062) and a relief counterbore (.245). The relief counterbore is to relieve the initial countebore to aid in getting the valve seats square when pressing them in. The operation was, center drill, undersize drill, .156 reamer, .1875 port drill and finally the counterbore tool.

 

[gbritnell]

This is the result of the port cutting operation. In the first picture you can see the relief counterbore which goes down just to the tangent point of the radius on the combustion chamber wall.

 

[gbritnell]

With the valve pockets cut the vise and angle table were pulled off the mill, everything cleaned up and the dividing head was set up and indicated. This would be used to cut the external flats and the drilling, tapping and counterbore operation for the spark plug hole. (10-40 plug)
The threaded mandrel was clamped in the chuck and indicated true. The first head was screwed on to the mandrel and tightened what I deemed the right amount without stripping out the small threads. The dividing head was set at -0- degrees and the chuck was loosened enough to turn the mandrel to get a true reading across the port face. Both of the external flats were cut and then the spark plug area was finished. It is convenient that everything is on 30* so it only required the one setup. The last picture shows the work up to this point. Still a lot to go.
George

 

[90LX_Notch]

George,

Your ability to make your own cutters is truly inspiring. What I wouldn't give to be able to have such an ability. Your work is always beyond words. I can not express my thanks and appreciation enough for the time that you take to document your builds so that others can learn from them.

My sincerest thanks,
Bob

 

[gbritnell]

Here's the progress report on the cylinder heads. I got to work most of Sunday and quite a bit of today on the heads. When I designed the head I removed stock around the valve guide area and the pad for the rocker pedestal. I had to tilt the dividing head straight up so that I could machine the outside angle and then do the stepping around the boss. When all the machining is finished I'll go back and clean up the steps and the area where the 2 angles intersect.

 

[gbritnell]

The milling part of the job didn't take as long as screwing each one on the mandrel and indicating it square before cutting.
With that out of the way I rotated the dividing head back to the horizontal position and indicated it for true. The threaded mandrel was replaced and the first head screwed on. The setup for this operation was quite a bit easier as I could use my precision square to get the proper alignment. This allowed the slitting saw to remain in place.

 

[gbritnell]

The final four pictures for today are the glamor shots with the cylinders and heads installed on the crankcase. Tomorrow I should be able to finish up the machining on the heads, putting the intake and exhaust ports in and the mounting screw holes. I can then start the hand work, grinding, radiusing and polishing.
George

 

[metalmad]

Hi George
Its just lovely Mate :bow:
Pete

 

[vcutajar]

Beautiful. :bow:

How I wish I was able to do all those things.

Vince