The Workshop Progress Thread (2016)

[JasonBModerator @jasonb]

I can't give it away that easily Bruce, but the engine has been discussed in the past on this forum though not in this form/size.

Any other takers for what it may be?

[David Clark 13Participant @davidclark13]

Jowett poppet valve engine?

Edited By David Clark 1 on 10/01/2016 12:15:51

[JasonBModerator @jasonb]

Yep, sorry no prizes though as you spelt it with an e not an i

Edited By JasonB on 10/01/2016 13:21:57

[Anonymous]

Nowt to do with the car maker then?

Andrew

[JasonBModerator @jasonb]

No Designed by Samuel G. Jowitt in 1904, you had a pair next to you at Stratfield.

Frame ends done

J

Edited By JasonB on 10/01/2016 15:24:37

[Anonymous]

Posted by JasonB on 10/01/2016 15:02:04:

No Designed by Samuel G. Jowitt in 1904, you had a pair next to you at Stratfield.

I try not to look at the other models 'cause i get depressed if I do.

Bit of a mixed weekend in the workshop, and carport. Yesterday I made the water pump bypass valves (303 stainless) and the parts for the operating handles:

Today I had a first go at welding a T-ring into a front wheel with the arc welder. Not pretty, but I don't think it's going to fall apart. And I hope a whizz round with the angle grinder and some U-Pol will hide the worst bits:

Andrew

[JasonBModerator @jasonb]

I take it that the bypass valve turns the water 90deg and sends it down towards the tender rather than passing straight through the spindle.

Wheel looks neat enough, was there much sign of distortion as the welding can sometimes cup the rim

Edited By JasonB on 10/01/2016 17:17:15

[Anonymous]

Posted by JasonB on 10/01/2016 17:16:51:

I take it that the bypass valve turns the water 90deg and sends it down towards the tender rather than passing straight through the spindle.

Correct.

The wheel rims are not flat, but are slightly cupped in some places, but not all. Looking at a wheel with a T-ring in place, but not welded, the rim is also slightly cupped in places. So the welding has made it a bit worse, but not markedly so. A quick measurement with a micrometer seems to indicate that OD of the welded wheel varies by about 20 thou. Given that the OD is 14.5" that's not bad in percentage terms.

Andrew

[JasonBModerator @jasonb]

Got the bearing caps and bearings done on the Jowitt

Also the exhuast chamber pluig and inlet valve seat insert

Edited By JasonB on 17/01/2016 19:37:02

[ianjParticipant @ians]

A short video of my now painted Farm Boy hit & miss engine with sound

 

Ian

Edited By ian j on 20/01/2016 20:59:34

[Martin WParticipant @martinw]

Ian

Looks and sounds great

Martin

[JasonBModerator @jasonb]

Ian, thats a very good runner and you have done a good job of blending in all the blocks of aluminium to make it look "cast". What are you using for fuel, petrol or Colemans?

[ianjParticipant @ians]

Jason B

It's runs on Colemans fuel using the J. Ridders petrol vapour carb. The first few times I had it running I used a 30/70% mixture of methanol/colemans but for some reason it will not run on that now !

There's still a tight spot between the two gears but after approx. 8 hours running it's getting better.

I considered your suggestion of grinding paste but thought it may be a bit too aggressive.

 

Any suggestions on another hit & miss engine to build from bar stock ( I have no welding facilities )

Ian

Edited By ian j on 21/01/2016 08:04:34

[Bruce EdneyParticipant @bruceedney59949]

After spending a good portion of yesterday turning a chunk of CI into a flywheel blank I spent a couple of hours setting it up and setting the CNC mill to form this

Quite happy with how it turned out

Bruce

[JasonBModerator @jasonb]

Posted by ian j on 21/01/2016 08:03:33:

Any suggestions on another hit & miss engine to build from bar stock ( I have no welding facilities )

 

I think The farmboy is about the nicest looking barstock engine but you could have a look at the Zero Six by Dario Brisighella. This is my version of it with Stuart turner cast flywheels, the base did have a bit of welding but silver solder would do the job or screwed & glued aluminium, cylinder/hopper is soldered.

Another option is Phil Duclos' Victorian which is a bit different to teh usual horizontal layout

The Parsell & Weed engines could also be done from solid or with the casting kits. Either use the model drawings or the original book can be found on the net which gives most details of a full size one that can be scaled to suit your machines.

 

Edited By JasonB on 21/01/2016 13:26:34

Edited By JasonB on 21/01/2016 13:28:12

[KWILParticipant @kwil]

Bruce,

I like the flywheel but I thought CNC was supposed to be a quicker way? A couple of hours, good result though.

[MuzzerParticipant @muzzer]

Hi Jason

Nice looking machine and a proper IC engine at that.

What do the curious counterweight thingies on the end of the crank do? They almost look as if they could be part of a governor but I can't see any linkage that could connect them to a control valve, yet they are too small to do anything to increase the inertia of the flywheel noticeably. I'd put my money on a governor component but am puzzled how it would connect up through the flywheel.

Murray

[JasonBModerator @jasonb]

Muzzer they are indeed governor weights, have a watch of this similar Gade running, you can see how the L shaped levers attached to the weights move a "spool" on the crankshaft which in turn moves more levers that activate a latch which as the governed speed is reached will hold open the exhaust valve making the engine "miss"

Static pics of the same engine

There are several variation on the theam but they all basically use a weight of some sort to activate a latch.

This one has a wedge shape to push the spool.

And this one the weight lifts a cranked lever

Edited By JasonB on 21/01/2016 16:35:57

[davebParticipant @daveb17630]

Governing is what they do, it's a hit & miss engine, the linkage is behind the flywheel. Lovely job!

[Bruce EdneyParticipant @bruceedney59949]

Posted by KWIL on 21/01/2016 15:27:47:

Bruce,

I like the flywheel but I thought CNC was supposed to be a quicker way? A couple of hours, good result though.

Kwil

A lot of time spent in ensuring fixtures were not going to be hit by collet chuck – about 45min to machine.

I am not sure I would want to tackle the curves on a manual machine

Bruce

[JasonBModerator @jasonb]

I have made quite good progress with the Jowitt over the last few days – crankshaft, piston, cams, valve gear, oil pots and a few other small items. Just the conrod and flywheels to go.

J

[Steve PaveyParticipant @stevepavey65865]

How did you machine the radii on the Jowitt cylinder block Jason?

[JasonBModerator @jasonb]

Steve, I'll be doing a full write up of the build with lots of pictures once I know it's a runner but until then.

Followed by a lick with a file.

J

[MuzzerParticipant @muzzer]

Sounds as if this is a poppet valved steam engine and I can see the cams on each end of the crank. This suggests that it's a sort of 2-stroke engine, if you like. Even so, the cams are remarkably "slow", more like eccentrics than lobed cams. Are they as originally designed / like the real world engine it was based on? I suppose if you wanted to tune it for maximum efficiency / performance you'd need to play with the cam profile.

I see there is a picture linked in this post.

[JasonBModerator @jasonb]

Thats the one, I have built it mostly as the original model drawings but could not find the real thing. I will leave the followers short of the "cams" so that will give them less open time and see how things go.

J

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