Has anybody built Beng's Danni Steam engine.

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That's a much better idea [and a lot safer] ... All you need is a little jig to fit the tool post, and fix the workpieces to that.

MichaelG.

Ian : I did think about using a vice but the parts are too small and awkward to be held in the vice. The vice might also damage the flat surfaces which are essential for a good seal.

Aha...perhaps holding the piece end on in the vice with the edges to be removed sticking out from the vice. I might try something like that next time.

Michael : I did think about a jig of some sort for the tool post but I could not think of anything. Do you have something in mind ?

NOTE : I was running the Dremel stone wheel at the slowest speed and using eye protection while I did so. I always use eye protection when using a Dremel.

Edited By Brian John on 11/10/2016 11:54:44

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Brian,

What I have in mind for items 22 and 23 ... just make an extended plate to fit the toolpost, drilled to suit the component.

If everything is reasonably accurate, so far; use two 2mm pins for location and a bolt through the middle ... cut one side, then rotate 180° to cut the other side at the same setting.

MichaelG.

Edited By Michael Gilligan on 11/10/2016 12:18:04

Michael : yes, I see now. I will try that next time.

The two steam chests are now complete. The instructions were right and the steam chest is quite a complex piece of work with lots of M2 blind holes and steam holes that have to be drilled to the correct depth. I had intended to drill and tap the steam inlet pipe for 3/16-40 but the hole is too shallow for those taps so I ended up going with my original idea of silver soldering a bushing into the steam chest. The bush is threaded 3/16-40 so that I can fit a displacement lubricator later. (At this stage I am not sure how the lubricator will fit neatly with everything else.)

I will make the control valve next. Now that I have completed the steam chest, I must get the valve to match the bore of the steam chest.

UPDATES : the vertical mill slide from China will not be here until next year...maybe January ! In the mean time I am still waiting for the fly cutter which seems to have gone missing in action.

I have started making the control valves : I made the main shafts from 4mm silver steel checking for fit with the steam chest covers. I drilled and tapped the ends of the shafts so that the joint parts (20) will screw in. I only needed 5mm of thread but I drilled the hole down to 10mm so that it was more like a through hole than a blind hole... less chance of a broken tap. I used plenty of tap magic and I drilled out to 1.7mm rather then the 1.6mm I would use for brass. It all went well with no problems.

The 6mm diameter parts I made from gunmetal bronze turned down so that it fitted the steam chest and then centre bored to 4H7 so that the silver steel shaft will fit through it. It was a fiddly job turning them down to 3mm wide after parting off !

How should the 6mm parts be fixed to the shaft ? I was thinking of using some sort of Loctite product but I am not sure if it would hold. I could also soft solder it and I think that might be the better option. I also considered pinning it somehow but I am not confident of drilling holes in the shafts.

Edited By Brian John on 16/10/2016 08:14:38

Edited By Brian John on 16/10/2016 08:16:37

I was not totally happy with my idea for the control valve so in case the retaining compound does not hold I have come up with a plan B. The control valve has been made in two parts using 6mm silver steel and 4mm silver steel joined together with M2 threaded brass rod which will be held in place with Loctite 222 (low strength). The only turning I had to do was reducing part of the 6mm shaft down to 4mm. I used the flat edged parting tool for this, taking small 0.05mm cuts while passing it back and forwards between the 6mm sections.

Drilling and tapping took longer than expected due to rubbish drill bits breaking ! I hade to remake the parts a few times. I bought some good quality 1/6'' (1.59mm) drill bits today from NQ fasteners here in Cairns. They only had two in stock but it was enough to get me out of trouble. I will join everything together tomorrow. I have screwed one together on the photo and left one in parts so you can see how it fits together. I think somebody suggested this idea earlier...many thanks.

UPDATE : the fly cutter has gone missing and nobody knows where it is at this stage. It left Melbourne 16 days ago. I am starting to think about making some sort of jig and filing the cylinder flat by hand.

Edited By Brian John on 18/10/2016 08:10:49

Edited By Brian John on 18/10/2016 08:14:13

Brian I don't want to discourage you but silver steel will rust if you run on steam. Should be stainless

Roy

But it will be oiled by the displacement lubricator so wouldn't that prevent it rusting ?

There is no way I am going to try drilling and tapping stainless steel...I had a devil of a time with the silver steel...or turning it in the lathe either !

Perhaps I should have made the whole thing out of gunmetal bronze which was my original plan.

Edited By Brian John on 18/10/2016 09:46:29

You could have made a simple fly cutter Brian. Say a round holder to fit in the 3 jaw chuck's reversed jaws. Hole drilled for round HSS and a grub screw to keep it in place. Maybe a bit of  flat ground for that to press on.

Some people make them out of square bar and add a morse adapter with a draw bar fitting but for a lathe really the round one is simpler. They can also be held in a 4 jaw for even more grip if needed.

Not sure if you are grinding your own tools yet though. Round HSS can be useful, Home made boring bars for instance.

John

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Edited By Ajohnw on 18/10/2016 12:24:56

Regards the control valve : I see that Minitech have both 4mm and 6mm stainless steel rod. I might be able to make it the same way as I did with the silver steel but without drilling and tapping. I would just use brass round 3/32'' (2.38mm) and Loctite to pin the pieces together. Drilling into stainless steel with a 2.3mm or a 2.4mm drill bit seems more feasible than drilling it with a 1.6mm drill bit....and no tapping involved.

I will not part off ; I will use the hack saw.

What grade of stainless steel is best for lathe work ?

Edited By Brian John on 18/10/2016 14:54:30

Edited By Brian John on 18/10/2016 15:03:54

Free cutting Brian. The other stuff can be pretty tricky.

John

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Go for grade 303 if they have it

Minitech in Australia only have grade 304 stainless steel. A google search has shown this to be difficult to machine. I will have to order the 303 from ebay/Hong Kong so it will be at least a month before it gets here.

The fly cutter has arrived after going missing in transit for two weeks ; nobody knows what happened to it.

Does this look even half right ? I have set the middle of the cylinder (marked with a black line) at the height of the tip of the fly cutter cone. Then I have adjusted the cutting tool so that it sweeps right to the edge of where I need the flat. This is my practise cylinder. I have drilled and tapped two other cylinders but I will not be using them until I get some idea of how this works.

Edited By Brian John on 21/10/2016 07:24:39

You need to do a bit of grinding on that cutting tool otherwise the edge marked in blue will catch the work and also not produce a square corner. Grind it where shown in red. If you look back at the one I posted a photo of you can see the shape.

I am having no luck with the fly cutter so I will revisit the idea of a vertical mill slide. This slide from India is the same size as the correct slide from Machinery House. I am not sure how it fits yet but I am sure something can be done to make it fit my lathe.

**LINK**

**LINK**

What would be a good size milling attachment to use in the lathe chuck for this job ?

Edited By Brian John on 24/10/2016 11:48:10

What probelms are you having with the fly cutter?

Getting the shape right.

Anyway, here is what the base of the mill slide looks like. The L276 from Machinery House only has one hole in the middle of the base whereas this tool has two holes. Other than that it looks identical and It should be okay to fit to my lathe somehow.

Edited By Brian John on 24/10/2016 18:21:57

Edited By Brian John on 24/10/2016 18:22:48

The vertical mill slide for the Optimum lathe is back in stock at machinery house. What diameter end mill bit would be suitable for machining the side of this cylinder ? I was thinking of the 6mm bit. I have not done any milling at all so I do not have a clue.

**LINK**

**LINK**

Edited By Brian John on 22/06/2017 10:10:48

Welcome back, Brian

MichaelG.