Ron’s Jowitt Popett Valve Engine

[Ron LadenParticipant @ronladen17547]

[Ron LadenParticipant @ronladen17547]

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.

[JasonBModerator @jasonb]

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.

[Ron LadenParticipant @ronladen17547]

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

[Ron LadenParticipant @ronladen17547]

Morning Jason,

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

Ron

[JasonBModerator @jasonb]

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

[John BaronParticipant @johnbaron31275]

I've been collecting the materials to make one !

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

[Jim NicParticipant @jimnic]

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

[Ron LadenParticipant @ronladen17547]

Posted by John Baron on 17/02/2020 08:28:09:

I've been collecting the materials to make one !

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

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.

[Ron LadenParticipant @ronladen17547]

Posted by Jim Nic on 17/02/2020 10:35:21:

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

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

[Former MemberParticipant @formermember19781]

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[JasonBModerator @jasonb]

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

[Former MemberParticipant @formermember19781]

[This posting has been removed]

[Ron LadenParticipant @ronladen17547]

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.

[JasonBModerator @jasonb]

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.

[Ron LadenParticipant @ronladen17547]

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

[Ron LadenParticipant @ronladen17547]

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

[geoff walker 1Participant @geoffwalker1]

Hi Ron

G'day mate, looks like another great build log

Keep posting

Geoff in Kings park Perth WA (Rick astley concert)

[Ron LadenParticipant @ronladen17547]

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.

[JasonBModerator @jasonb]

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

[JourneymanParticipant @journeyman]

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

[Ron LadenParticipant @ronladen17547]

Thanks guys but maybe my description is wrong, I dont mean a sprung tapping guide the ones I have seen are a length of bar, I,m guessing but maybe 6-8 inches with a small sprung centre. Used with a DTI in centering a workpiece in the 4 jaw, you have a picture of one Jason in your build thread when doing the cylinder..?

[John BaronParticipant @johnbaron31275]

Hi Ron,

It wouldn't take more that 1/2 hour to make one !

They are basically a bit of pointed rod in a tube with a spring behind it.

[John BaronParticipant @johnbaron31275]

Hi Guys,

Even easier a plastic chopstick with the end turned to a point and held in tailstock chuck.

Edited to say I've just made one !  I cheated and used a pencil sharpener to make the pointed end.  Five minutes tops.

 

Edited By John Baron on 20/02/2020 19:24:07

[JC54Participant @jc54]

Is this what you are looking for? I made this out of a bit of bar in the"will come in handy" box. One of the first things I made with my 1906 Drummond lathe.

John

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