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jlchapman

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I know there has been a couple of Webster in progress here. Might as well have another.

So, I started with the cylinder head. I used the mill for all the operations on the head. I debated whether to start with the cylinder or the head first. I wanted that snug fit for the cylinder into the head. Either way works great. I'm going to use my disc sander later to round the corners. I've been working on this for the past couple of weeks and should have taken more pictures.
I should mention, I'm a big fan of using an edge finder and a DRO. On real critical parts, I use blue dye and measure where the holes should be, then verify the location using the DRO.
Cylinder Head.JPEG
 
For the cylinder I ordered some oversized 1.25 easy to machine cast iron rod from McMaster Carr. I cleaned up the exterior of the cast iron rod using the lathe. I faced one end, center drilled, then drilled thru to 2.75" using a 5/16" drill bit. The cylinder only needs to be 2.5", this also me to correct possible mistakes later on. Then using a .750 drill bit drilled thru the bore. I'll use the mill to finish the bore to .873. Cut the cylinder off in the horizontal saw.

Using the milling machine I bored the cylinder out to .873. I make a plug on the lathe at .873 with a chamfered edge so I can sneak up on .873. I measure a lot but like the extra check. Be careful when boring with taking to big of a cut. When taking big cuts your boring bar will deflect. Whats a big cut? maybe .010 - .015.

I'll finish the last .002 of the bore using a wheel cylinder hone to create a cross hatch pattern.
IMG_4174.JPEG
873plug.JPEG
 
looking good. if using store bought piston rings you may want to wait until you have them in hand before finish boring and cutting the piston.
 
Thanks Werowance!

I already have the rings. Otto's was very quick shipping. I remember the first time going to a machine shop to get my 350 Chev bored out .030. The machine shop would do nothing until I brought the new pistons in. Same applies to these small engines.
 
Well I finished the flywheel. I was dreading the aluminium hub machining. I saw where Brian made a tool. So I watched some youtube videos on trepaning. Ground out a tool and it was quick and easy machining. I've attached some of the pictures of the tool. Sorry the pictures are a little out of focus.
IMG_4178.JPEG
IMG_4182.JPEG
 
I had some leftover bronze tube that I bought for the hoglet. So I made an aluminium hub and pressed and loctited into the bronze. The flywheel is really heavy. I drilled the holes at .625, I thought it looked better than .750. I used my DRO on the mill and Little Machine Shop PCD calculator to layout and drill the holes. Little bit of chatter from my tool machining the aluminum, I hope it cleans up.
IMG_4176.JPEG
IMG_4177.JPEG
 
Its been a work week so not much time in the shop. What time I did have I spent working on my Spring Winder project. https://www.homemodelenginemachinist.com/threads/spring-winder-build-your-own-springs.31666/ Its almost finished, so I worked on the base of the Webster. Pretty basic stuff. I rounded the corners on everything by using my disc sander. I need some more time to jazz it up. I used a roughing end mill to square up the pieces. I did not leave enough material to sand the marks out. Something to watch for next time. It also makes a big difference on what side of the Aluminum plate you want showing.

IMG_4226.JPEG


IMG_4228.JPEG
 
For the crankshaft bearing, I ordered from Stock Drive products. 5/16" I.D. X 1/2" O.D X 5/32" THK., FLANGED P/N A 7Y55-FS5031

There pretty proud of them but I liked having the flange.
 
Whenever I've looked for bearings sized in inches, they always seem to be much more expensive than metric bearings. It would require just a bit of modification to go with an F608 or F688 bearing - 8mm rather than 5/16", so the shaft would need to be .315" rather than .313", and you can get them for less than $1 each on Amazon (with Prime shipping, no less), or for half that on eBay. But of course, if changing to 8mm means having to buy new reamers, etc., it may not be worth it.

As I am playing with design ideas for a modified Webster build, I am planning to use metric bearings, but I will probably re-size the shaft to 10mm and use F6800 bearings, so that I can more easily use a key to secure the flywheel and gear to the shaft. Still, I'm just trying out ideas, so that may change!

On edit: I just realized that the OD of either the 608 or 688 will be a good bit bigger than the 1/2" of the bearings you are using - 22mm or 16mm, respectively. However, you can get F678 bearings, measuring 8 x 12 x 3.5mm, which would be close to (but a bit smaller than) the OD and thickness of the bearings you are planning to use - a bit more expensive, but not much.
 
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Well, now that I'm saving time by not having to commute. I machined a crankshaft today. I just made the simple one according to the plans. I used some stay brite silver solder. Hope that holds up.
crank.jpeg
 
I did have a question on where the crank spacer goes. See attached photo. I believe it goes as in the photo or I did the wrong dimension on the cylinder head-frame.


crank spacer.jpeg
 
Great work! Yes, there should be a spacer between the crank and the bearing. You might also want a spacer between the crank and the rod - two smaller spacers on either side instead of just one on one side.
 
I’m gathering materials to build a Webster, and I find that the gears are PRICEY to say the least. I’m considering cutting my own gears with a single point cutter, or going to a cheaper 40 and 20 tooth import gear instead. The problem with these cheaper gears ($8 versus $45)? Mod 1 diameters are different! On my Henry Ford Kitchen Sink Engine, I was able to utilize these type of gears because I could change the position of the cam gear without any problems.

Can I get away with changing the location of the cam gear on the Webster without screwing up too many other dimensions?

John W
 
John W, I would think you would just have to adjust for the cam gear position and pushrod height position. Changing the push rod height/angle may effect opening the valve. I'm sure somebody will have a better answer.
 
John, I used module 1 gears on my modified Webster. I designed it for 24-tooth and 48-tooth gears, but it would have been possible to do 20- and 40-tooth. Key question is whether you have already drilled any holes in the frame / support piece for the gears called for in the original; if so, you'll have to figure out a way to "move" the one for the cam gear in particular, and maybe also the one for the rocker arm.
 
John, for 45.00 you could purchase the 2 different module 1 gear cutters from ebay. that's actually what I did for mine. yes I had to make an arbor for them but that was out of scrap metal. and they were very slow getting to me from china.

on relocating, I suppose If I had to do that it would be the cam gear on the idler shaft. but moving that shaft would involve recalculating the rocker arm position or shape as that gear has the cam for the rocker arm on it. or maybe if you just move the gear up or down a bit instead of back or forward then you could probably just get by with thinning the rocker arm on one side or the other or both or thickening it. but moving the gear back or forward would probably cause more work that its worth.
 
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