Has anybody built Beng’s Danni Steam engine.

[Ian S CParticipant @iansc]

Brian, for soft jaws on the vice you don't want them very thick at all 1.5 mm aluminium would be ok, the square bars will tend to tilt, and(for me) brass is too expensive to use that way(its next to gold in my workshop).

You should be able to file that flat in 10/15 minutes with a good file not used on steel.

Ian S C

[Brian JohnParticipant @brianjohn93961]

I found some small aluminium strips today at Norweld but they have still not solved the problem of the top coming slightly away from the milling vice.

I have to make the flat 4mm from the edge of the cylinder. How do I measure that without removing the work piece from the vice ? I cannot get my digital vernier in there and I am trying to avoid removing the cylinder all the time.

I am advancing the carriage by 0.25mm at a time, How much of the 12mm cutting bit should I be using when taking a cut : 1/8, 1/4, 1/2 ….the whole thing ? Using the whole bit tends to cause it to dig in as you can see from the photo.

This is my practise cylinder so I can afford to experiment a little on this one. I still have two more cylinders to mill after this ( I am building two engines at once).

Edited By Brian John on 31/07/2017 08:25:42

[JasonBModerator @jasonb]

As I said tap the cylinder back against the slide as you tighten up the clamping screws.

Make a not of the handwheel setting when the cutter first contacts the work and then it will be easy to feed it in a toatl of 4mm (16 cuts @ 0.25mm)

For the roughing cuts go about 2/3 the cutter width so 8mm again as I said earlier start with light cuts and see how it goes, if you are getting dig ins then reduce the cut.

[Neil WyattModerator @neilwyatt]

Filing it would be easy with a filing rest, something that has gone out of fashion now everyone has a milling machine.

Starting with a nice bastard cut file, that wouldn't take long in brass.

Neil

[Brian JohnParticipant @brianjohn93961]

Yes, I was thinking that myself but can you even buy a filing rest now ? How much do they cost ?

[roy entwistleParticipant @royentwistle24699]

Brian John It's not a lot of trouble to make one

[Brian JohnParticipant @brianjohn93961]

If you know what you are doing…..

[Neil WyattModerator @neilwyatt]

Posted by Brian John on 31/07/2017 11:40:28:

Yes, I was thinking that myself but can you even buy a filing rest now ? How much do they cost ?

I never heard of anyone buying one

Neil

[Ian S CParticipant @iansc]

I made one, it's very simple, just two rollers and a hight adjustable pillar, with a base that clamps to the lathe bed. You just have to scale it to fit your lathe.

Ian S C

[Brian JohnParticipant @brianjohn93961]

So I have modified that top piece of aluminium so there is no overhang obscuring my vision (photo1) and I finished milling the first cylinder (photo 2). You can see where I had a bit of a dig in but when the steam chest is fitted this will not be visible as it will be underneath. It should not affect the operation of the engine. Hopefully my next two cylinders will turn out even better than this. Definitely only 0.25mm cuts on my machine !

The cylinder still has to be drilled at tapped at each end for the cylinder covers then two holes drilled in the milled flat surface. I will then have to smooth out the inside of the cylinder after the drill bit has gone through and remove the ragged edges from the holes. I should have left polishing the inside of the cylinder until last !

Edited By Brian John on 01/08/2017 08:06:40

[PeroParticipant @pero]

Mea culpa, mea culpa. I admit to purchasing one for my Cowells ME90. Very nicely made as one would expect if a little pricey. However, it does go very well with all the other accessories.

I must however make one for the Myford which is more likely to be used in anger (or more likely thrown across the floor in disgust, couples with the use of Old English, when I make a boo boo while constructing it).

Possibly coming in at number 96 on the list of things to do (in the workshop not around the house) unless a sudden need arises …..

Pero

[Brian JohnParticipant @brianjohn93961]

The first milled cylinder is on the previous page (8).

I seem to be limited to cuts of 0.25mm on my machine. What size cuts on brass could be taken on a decent size lathe, say a Sieg C3 ?

Edited By Brian John on 01/08/2017 14:20:57

[Brian JohnParticipant @brianjohn93961]

We have discussed the use of solder paste before : to join the steam chest to the milled flat on the cylinder as per the instructions. What temperature solder paste should be used ? Most of the solder pastes on the market seem to be for electrical work so I think it would be unsuitable for engineering.

I am also thinking of fluxing both sides, put some 243 degree soft solder between the pieces like a ''solder sandwich'' then apply heat. The only problem might be stopping the top piece from sliding about once things become hot and fluid. 

NOTE : I did buy some solder paste from the US months ago but I lost it in the shift to the new house !

Edited By Brian John on 02/08/2017 01:31:28

[JasonBModerator @jasonb]

If using separate flux and solder the correct way is to "tin" both surfaces and then "sweat them together"

Tin- flux the surface and then heat, apply a light coat of solder to the surface and while still hot wipe off any excess a natural fibre rag will do to wipe the solder off. Allow to cool

Sweat take the tow pieces, apply more flux to one and then place the two together and heat, you can add a little more solder feed in from the edge if needed when what was used to tin flows

[Brian JohnParticipant @brianjohn93961]

I knew there was something else : there are two 2.5mm holes on the cylinder flat which mate up with two holes on the steam chest (24mm apart). I would think that these holes should not get blocked when soldering the two pieces together. The instructions mention nothing about this. What could be placed in the holes to be removed later in order to avoid these holes being clogged with solder : timber, aluminium wire, stainless steel wire ?

[Ian S CParticipant @iansc]

You could probable stick a match stick in the hole, it would also help to locate things while you solder as things can skid around a bit on molten solder.

Ian S C

[Brian JohnParticipant @brianjohn93961]

A matchstick or some stainless steel ?: I have some 2.3mm stainless steel rod which fits nicely in the 2.5mm hole. I worry about timber igniting.

I finished the second cylinder today. Should the milled surface be touched up with a file or just leave it as is ?

I found that by drilling three 5mm X 2mm deep holes in the aluminium top plate that the screws on the mill slide could be more firmly located. This stops the cylinder pulling away from the vice. The two washers when held side by side measure 3.8mm so that gives me an idea when I am close to the required 4.0mm. There is no need to remove the work piece to measure it.

Edited By Brian John on 04/08/2017 10:14:02

[Lawrie BradlyParticipant @lawriebradly72996]

Hi Brian, I'm yet to mill the three cylinders I'm working on (one for the single cylinder Bengs kit and two for the twin cylinder scratch-built version), but I too have been thinking about the posssibility of the inlet holes being blocked by solder and the need to adequately line up the holes. I too was thinking about using stainless steel pins to locate the steam chest against the inlets, but it might be a big ask to get the holes on the steam chest and the cylinder to line up absolutely exactly to fit metal pins. I am thinking that using matches might give a bit of leeway, even if it does start a nice wood fire when soldering, it might be possible to just blow out the ashes. I am still weighing up the options. Regards, Lawrie.

[Lawrie BradlyParticipant @lawriebradly72996]

A question to anyone. The other thing I'm worried about is that initially drilling the steam chests I just used a ruler to mark the holes. That was before I figured out that using the graduated wheels on my Optimum mill/drill gave greater accuracy. As it stands then, some of the holes I initially drilled (now measured with a digital vernier caliper) are around 0.2mm to 0.3mm out of position – in relation to the valve slide or piston. My question to everyone is, how critical are these measurements – what tolerances should I allow. Should I remake the steam chests before I go anywhere near soldering anything to the cylinder? Regards, Lawrie.

[JasonBModerator @jasonb]

Brian, will be fine to solder straight onto that milled surface. A bit of tipex correction fluid on any surfaces you don't want solder to take to will also help, at soft soldering temps a bit of charred wood won't do any harm.

Lawrie those slight deviations should not cause major issues.

[Lawrie BradlyParticipant @lawriebradly72996]

Jason, Thank you. Sounds like good advice. I have been thinking that timing the engine within its inaccuracies will be what it will be all about in the process of getting it spinning. I think I'll just forge ahead. Regards, Lawrie.

[Ian S CParticipant @iansc]

It would depend on your method of heating, I would be using a large soldering iron, but you maybe using a torch, in which case the stainless wire might be better. My way, tin both surfaces, put in place and aline the holes, plonk the soldering iron on top, if a solder fillit does not form, apply a little extra solder to the edge, hold the top piece down with a screw driver and remove the soldering iron, then wait for the joint to cool down before letting go. The thinner the joint the stronger it is.

Ian S C

[Brian JohnParticipant @brianjohn93961]

I have been thinking about the soldering of the steam chest to the cylinder while I complete the milling of the cylinders. The solder must fill the two inner holes on the side of the steam chest (the two outer holes will be plugged with timber or stainless steel to keep them open). The solder must also fill the two holes at each end of the steam chest. It all seems a bit ''iffy'' hoping that the solder is going to find its way into all the holes and do the job. Is there some way that the holes could be plugged PRIOR to soldering the steam chest to the cylinder ?

Edited By Brian John on 05/08/2017 09:47:04

[JasonBModerator @jasonb]

The solder does not need to fill any of the holes.

You are basically sticking a flat (cylinder) surface to the area around the hole which will seal it just like if you put a bit of sticky tape over the hole.

Infact when you tin the surfaces you could keep the solder a couple of mm away from the holes which would help with reducing the risk of them filing with solder.

[Lawrie BradlyParticipant @lawriebradly72996]

I thought people might be interested in photos of the bits for the single and twin cylinder versions of the engine, I have made so far. I had a bit of trouble getting the photos up, so I hope it works.

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