# Yet Another Webster



## Blue_Rock (Oct 1, 2011)

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.


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## Paulsv (Oct 2, 2011)

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


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## Blue_Rock (Oct 3, 2011)

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.


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## Gedeon Spilett (Oct 3, 2011)

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


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## Blue_Rock (Mar 18, 2012)

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.


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## metalmad (Mar 18, 2012)

Hi BlueRock
Top Job Buddy
Pete


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## Blue_Rock (Mar 19, 2012)

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.


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## HYTECH (Mar 19, 2012)

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


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## Blue_Rock (Apr 9, 2012)

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.


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## mnay (Apr 9, 2012)

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


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## ShedBoy (Apr 9, 2012)

Great looking engine. Looking forward to seeing it run.

Brock


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