Ron's Jowitt Popett Valve Engine

I think I can squeeze in another project before getting back to the Class 22, I am going to have a go at a Jasons MkII version of the Jowitt Popett Valve Engine.

I think Jason said it is approximately 30% larger than the original having a 24mm cylinder bore. Fortunately Jason has one of his excellent build threads complete with drawings here on the forum so that is a real bonus.

I really like the look of the engine and its a bit more advanced than the little Muncaster oscillator I have been building so a bit of a step up so to speak.

Still waiting for the flywheel to finish the oscillator so having some material to hand I made a start on the Jowitt side frames this morning, going well so far.

I thought you had been a bit quiet this weekend Ron, now I can see why. You look to be off to a good start.

Thanks Jason, I did spend a fair bit of yesterday reading your build thread (twice) and studying the drawings to make sure I was happy which I am.

You probably noticed that I did live a bit dangerously today though, I should have set the frames up a bit further out of the vice. I was half way through cutting the large rad when I thought I was going to crash into the vice. I checked the dimensions and fortunately I cleared the vice at full rad buy a gnats whisker about 0.6mm..

Edited By Ron Laden on 16/02/2020 16:26:36

Edited By Ron Laden on 16/02/2020 16:29:09

Morning Jason,

Just out of interest do you know how many of your MK11 Jowitts have been built.

Ron

JimNick on here has made one, Chris Gunn did at least three and a couple of others that have posted.

I've been collecting the materials to make one !

I just need a piece of cast for the cylinder block.

Hi Ron

As Jason says I built a Jowitt from his plans.

You may see the resemblance. Being a bit careful with a penny, I made the flywheels rather than buy in a pair of castings. The wee brass pulley came from my come-in-handy drawer.

Jim

Edited By Jim Nic on 17/02/2020 10:35:48

John, I am going with aluminium for the cylinder, Jason mentioned in his thread that alu was an option so thats what I am going to try.

Very nice Jim, I hope mine turns out as well.

I think it a really nice looking engine, the shapely cylinder block and the twin flywheels. Also watching Jasons videos it sounds good to.

Ron

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Bill, I give some history of the engine in my thread here

I don't think I had this photo at the time I did the build but it shows most of an original casting set with aluminium cylinder casting. Photo by Jo T.

Edited By JasonB on 17/02/2020 14:11:18

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The side frames are just about there, still need to machine the 3.6 degree angle to the ends and sides. I have sent off for a digital protractor, I have been meaning to get one for a few weeks so now is a good time.

I machined most of the side frames with the ARC 25mm two insert end mill. I have been using it a lot lately, very good should you need to remove a fair amount of material and the surface finish is excellent, really impressed with it.

Ron, the angle is not critical but if you can't wait for your new toy 3.6degrees works out quite close to 1/4" in 4" or 3/8" in 6" so easy to arrange some packing at those distances to set things up.

Thanks Jason, if I had thought about it a bit more I should have realised that the angle is only cosmetic so close enough will be ok. I will give it a go in the morning.

Ron

Up early and machined the angled ends and sides, went well and the transition to the vertical at the crank mount turned out ok.

Hi Ron

G'day mate, looks like another great build log

Keep posting

Geoff in Kings park Perth WA (Rick astley concert)

Would anyone know where I can get a sprung centre for the lathe, I must be looking in all the wrong places as I havnt found one yet, well I tell a lie I found one but I am not paying £56 for one.

I also wondered if its ever been featured in tool making over the years, I cant imagine they are too complicated.

I know a very nice man who would be only too willing to sell you one. or even more.

Personally I don't use them just a bit of silver steel with a point held in the tailstock chuck and push the tailstock to keep the pressure. Hole in the other end drilled with a CTR drill will allow you to use taps that don't have a hole in the end.

Or are you looking at my long one for setting up work in the 4-jaw?

Edited By JasonB on 20/02/2020 15:53:15

Found *** These *** on Amazon, no idea if they are any good but there must be others about.

John

Jason beat me to it by a few seconds: The ones from Arc are about the same price as Amazon so definitely a better bet.

Edited By Journeyman on 20/02/2020 15:53:52