1/2 scale gade

[NickG]

That fixture did a good job.

[Ken K]

  If you would like pictures/detail of fixture, let me know. I can cover it.
  Put the head back, in the fixture, to cut valve ports. I used a piece of .187" drill rod to center the
hole, the mill on the .187" hole in head. Then drilled to a .625" hole, .750" deep. The plans show
a flat bottom for the hole, so used a 5/8" end mill to cut .800" deep. Used a 90 degree counter
sink to cut valve seat. Will do the other hole, the same way.

[NickG]

Ken, have you used the countersink to cut valve seats before? It looks good but others I've seen have gone to great lengths making their own cutters etc - i guess one advantage is that you can use the same setting on the compound
slide to so the valve and the cutter ensuring they are the same?

[maury]

I have made my valve seats both ways. I have had good luck using a countersink if the seat can be cut in the same setup as the valve stem hole. Some designs require the valve stem hole to be drilled from the back to get it centered nice on the casting. In that case I think it's more or less necessary to make a tool with a pilot.

maury
www.lonestarengineworks.com

[Ken K]

 I cut the valve seat this way because I know the head was flat/centered, due to the fixture
 With heads that I do not think I can hold right, I used the cutter with pivot. The picture shows an
old style cutter. 1/8" hole to 3/32" pivot.  The main reason to show it is, you can adjust the size of
the pivot, up, or down a 1/32", using brass tubing. The one use now is a 5/8" counter sink, with a
1/8" hole. If you take a 90 degree counter sink, grind a 1/8" + flat on the end, chuck in lathe, then
drill a 1/8" hole in the end, using a new ( sharp) 1/8" carbide end mill, you get a seat cutter,
without having to make the cutter. Friend is using mine, so no picture.

[Ken K]

 Cut the ports flat. Layout, and drill, then tap 3/8 NPT. Make sure you use a center point, to
insure tap is straight. Head just needs mounting holes, drilled to size, and spark plug hole drilled, and tapped.
  Milled the inside of mains.

[Don1966]

One thing I can say about your work Ken, is that you are all business. Nice work as usual.

Don

[Ken K]

    Time to cut the holes, for driven gear, and crankshaft. Start by getting the angle plate square.
Drill, ream, and  face cut driven gear hole. Drill and ream the crankshaft hole to .625" , put .625"
drill rod, in hole. Mount drive gear, and driven gear, and using a piece of paper, check the fit.
The paper should feed, between the gears, without tearing, and you should not be able to pull it
up, and out. Looks good, so will finish hole to .750".

[b.lindsey]

Great progress as usual Ken!!  I can see how that mounting plate comes in handy for all these set-ups too.

Bill

[Ken K]

Time to make the valves.  Fine lapping compound, 30X scope, with light, layout die and pin
vise. Drill, and ream hole in stock, and part off. Cut some drill rod about ½ to 3/4" inches longer
then needed. Put grooves in end of stock, so silver solder, has a place to flow, on head. Silver
solder, stem, to head. Have a Taig lathe, that has a collet that holds valve on center, that I use to
cut face, diameter, and 45 degree. Now that the valve is cut, put compound on, put valve in head,
and use drill press, to turn it. Doing this put a groove in the head, which needs to be filed out,
using lathe. I make the valves thicker then called for, so I have a good size flat, to put the file on.
Picture shows how layout dye show area not cut. You can also see, that the counter sink drill did
a little chatter. Cut seat, file groove till you get a clean cut, all the way around seat. Now file
valve flat, put lay out dye on, and use pin vise to turn valve, a few times, and check with scope,
that you have a clean cut, all the way around seat. Cut valve head to size
 The final test is when you put the engine together, and you can not feel any pressure, at intake,
or exhaust port, when you turn engine over.

[Ken K]

    Time to make some valve springs.  There are a lot of ways to make springs, but this is how I do
it. Picture showing what is needed to make the springs. Heavy leather gloves to put tension on
wire, when winding, .036" and .022" spring wire, as called for in plans, good side cutter,  and
transfer punch set, for mandrel, to wind spring on. I buy the spring wire in 1/4 pound rolls, by
mail order, as I can not get it, in town.
 To wind a spring I put lathe, in lowest speed, (78 RPM), clamp wire and mandrel, in three jaw,
and wind spring, with warps close togther. When you cut the wire, the wraps spring open, the
smaller the wire the more spring out, you get. Takes a few tries to get the right diameter of spring.
When you have right diameter, remove from mandrel, count in 3-5 wraps, and put a piece of paper
to mark. Count down the number of wraps called for, in plans, and but another piece of paper.
Replace paper with thin flat stock, and pull to open wraps. Cut off end wraps till you have two
close wraps left, and adjust length, to what called for. Grind end flat. The spring should stand
straight up when put on end. Note finished springs, in first picture.

[Ken K]

 Got the key ways cut in flywheels, belt pulley, and drive gear. Center drilled a piece of 5/8" drill rod, and cut a 3/16" key way in it. I will use this to cut the belt pulley, between centers, using the cross silide set at 2 degrees, as called for in drawings. Then use a file to cut up, and round crown.

[Ken K]

 Back to cutting on the flywheels. The flywheel is bigger in diameter, then the cross feed clearance, so had to put cutter way out, to cut outside of flywheel.  Did the job, but don't like to do that, to much flex, in tool. Cut the other side of tire. Cut flange, and step between tire, and flange. Boring bar work well, for this task.

[Jasonb]

Ken if you can run the lathe backwards you can use a similar setup to your last photo with the boring bar upside down which will reduce tool overhang a lot. Reverting to a 4-way toolpost can also help.

[Jo]

Or use a right hand tool in the tool post and run it the normal way 

Jo