Yet Another Webster

[Blue_Rock]

Hi, I've been slowly progressing with my Webster build for a several months now and I'm up to the stage where it gets a bit more challenging, the valve gear.

This is my first engine build and I'm learning heaps from reading others' posts here on HMEM.

My build is a little different as I'm going to use bearings rather than bushes for the big end and the mains. I'm also planning to use a magneto? ignition system off an old line trimmer that I bought from a recycling centre for $5.

I have already made the base and other larger parts including the cylinder, head, con-rod piston and crank.

To lap in the cylinder bore, I made a lap from brass and it can be expanded by tightening up two grub screws that force open the the slit that runs along the length of the lap. I used diamond paste with the lap that I rotated slowly in the drill press, while moving the cylinder up and down, using progressively finer paste with the lap until I had a pretty smooth finish inside the bore.

The crank is silver soldered together. Until this build, I'd always used 2-5% silver solder when soldering up larger mechanical parts or copper pipe. However, I soon found out that this percentage solder appears to not be suitable for finer work as it does not flow as readily as 45% that I ended up getting hold of to do the crank. I left about 0.10mm (0.004") clearance between the parts of the crankshaft for the solder to flow into.

 

[Paulsv]

Looks like great work! The magneto ignition is interesting. I can't wait to see how that goes.

 

[Blue_Rock]

Hi again. Today I cut the timing gears using a hob cutter that I made from silver steel (drill rod). I found these webpages really useful for an explanation of how to make a hob cutter - http://www.metallmodellbau.de/GEAR-CUTTING.php (in German but Goggle translator works OK) and also this page - http://www.helicron.net/workshop/gearcutting/involute/. I also found the book Gears and Gear Cutting by Ivan Law to be pretty good too.

Before I made the Webster's gears, I tested out the hob cutter and made a wide 20 tooth gear and cut it in half, making two 20T gears, to check whether the gears would mesh OK. That test worked out so I went ahead and cut the final gears, a 20T module 1.00 for the crankshaft and a 40T for the cam gear.

I set up the blanks in spindles held in a drill chuck and machined down the blanks to 22mm (crank) and 42mm (cam). I then transferred the drill chuck, without moving the blanks, to the rotary table set up on my mill. I used the rotary table because I don't have a dividing head.

The gear cutting went smoothly, albeit a bit tedious, with all those teeth and keeping my wits about me to make sure I was advancing the gear to correct amount each time.

The last picture shows the finished gears but it looks like they are not meshing quite far enough. Maybe I did not have the cutter in deep enough? Anyhow, they spin against each other very well and don't bind so I am going ahead and using them on the engine.

Next up is the exhaust cam.

 

[Gedeon Spilett]

Hi

Maybe I did not have the cutter in deep enough? Anyhow, they spin against each other very well and don't bind so I am going ahead and using them on the engine.

I would have said the opposite if the distance between the wheels is as expected!
A nice work you are doing.
I hope to start soon my Webster, still some metal to mine
Cheers
Zephyrin

 

[Blue_Rock]

Well it’s been a while since I’ve updated this thread but I have been plugging away on the build. Since I last posted, I’ve upgraded my lathe to a CQ6230 12” x 36” with power crossfeed etc (similar to a Grizzly G4003) and also got hold of a larger mill, a RF20. I got both these machines from a deceased estate sale along with a whole stack of tooling and some materials, so I've also been busy setting up those machines and reorganising my workshop.

I’ve made all the webster’s valve gear and it took me a few goes to make the various parts to my satisfaction. The stainless valves were a bit of a challenge being so small and a bit fiddly but I eventually go them done.

The ignition setup is from an old line cutter (whipper snipper) and the coil-carrying bracket pivots about the crankshaft on a bronze bush. This enables the ignition timing to be adjusted. I milled a curved slot in the bracket that locks the coil bracket using a rotary table in a setup that I saw another forum member use when he was milling the mounts for his beautifully-made tilting vice.

I’ve now only a few bits and pieces to finish off and also a vapour fuel system to make and I can fire her up. Still a few weeks off though.

 

[metalmad]

Hi BlueRock
Top Job Buddy
Pete

 

[Blue_Rock]

Thanks Pete.

It's been a fun project to learn some basic machining skills.

Looking forward to the thrill of firing her up for the first time.

 

[HYTECH]

We look forward to it too! Can't wait for the video.

 

[Blue_Rock]

Hi, I managed a bit more on the build this weekend.

Made the lid for the vapour carby/fuel tank and trepanned the lid to take an o-ring seal.

The stepped bracket will have a screw on the long end that will push the lid down to seal it. My first design had beveled edges on the bracket but I thought that a rounded finish would look better. An hour or so later after a lot of filing and sanding the bracket is ready to be drilled.

 

[mnay]

Great job on your version of this engine. I like you innovative ignition system. It is fun to make changes to an existing design and make you engine unique.

I will follow with interest.

Mike

 

[ShedBoy]

Great looking engine. Looking forward to seeing it run.

Brock