Member postings for Gas_mantle.

Hi all,

Thanks for the replies.

The irony of it is, the plans had it as a vertical engine with the flywheel at the bottom, I decided to build it as a horizontal but the engine has decided it is a vertical with the flywheel at the top !

Brian - I think part of the problem is the Kelly kettle has a small surface area of water at the top, it also needs to be reasonably full so I get a lot of water entering the tubing in relation to the steam generated. It's far from ideal as a boiler.

Ian - it does run better when it's hot but still struggles when horizontal, it may even improve on its own after it's been run in a bit

Peter.

Hi,

Here's a short video of it running on live steam, it can be seen how it runs better when upright.

I'm inclined to think it's an issue of water in the cylinders rather than friction problems (when not connected to the steam line it spins freely with little friction)

The Kelly kettle I'm using as a temporary boiler throws out a lot of water and think that's a lot of the problem rather than the engine itself but would be interested what others think is the cause.

**LINK**

Peter.

Many thanks to everyone who followed this thread and offered their encouragement.

I can now say I've got the little engine running on live steam, (I made a new valve piston) it's still very sensitive and struggles when horizontal but rattles along in an upright postion.

Hopefully the fact it runs ok upright suggests there isn't much wrong and it should be simple enough now to sort it out.

I've only had a lathe a few weeks and this was the first thing I made, I've never done anything like this before so although it was a simple project compared to many on this site I'm very pleased with it and enjoyed every minute of making it.

I don't have a youtube account but if anyone wanted to see the engine running I'll resister and upload a video (can I upload one direct to this forum ?).

Peter.

Thanks Brian,

I'm wondering if it may run better on air anyway.

For reasons I don't understand it works better pointing skyward with the flywheel uppermost !

It's very sensitive to adjustment, I put an allen grub screw in the eccentric to allow for valve timing adjustment but under live steam it soon gets scalding hot and a pain to adjust.

I'm still pleased with it though, it needs a few minor glitches sorting but it does cough an splutter along now if I catch it right so I don't think there's a great deal wrong with it in principle.

Peter.

Hi all,

I set about trying to finish the engine yesterday and hopefully give it a test run.

Firstly I needed a better wrist pin than the temporary staple I was using. It involve turning a piece of brass rod down to about 1.5mm but with care that shouldn't be a problem.

At about 2mm the rod is starting to flex and the tapered cut I'm getting becomes apparent, thankfully the Poundshop sell these blue travelling steadies at 6 for a quid in the biro section

The taper seems to have gone

Eventually I arrive at this,

1.55mm and just right.

Cut to length and the end lightly peined over all seems ok.

The wrist pin needed to be just short of the end of the cylinder at maximum travel and have a 3/16 stroke, so I'm hoping I've achieved that with sufficient accuracy.

With the wrist pin done all that's needed now is a few spacers for the axle and then a test run.

I'm satisfied this is the alignment needed, so I need a spacer with a disc to keep the eccentric in place then possibly another one between the eccentric and crank and finally a small one behind the fly wheel may help.

A steel bar turned at one end to 16mm (the eccentric retaining disc), reduced down to a smaller diameter for the spacers and drilled to accept the axle.

A bit of a makeshift idea but I reckon the eccentric disc/spacer need to be 6.5mm

So using this crude method I cut small reference grooves in the work piece marking the parting cut position. I did the same method for the other spacer hoping I'll get 3 components in one procedure.

Parting tool at the ready and here we go, buy 1 get 2 free.

I took the next photo at the wrong time, it should show the tool further left to part off a disc for the eccentric, but you get the idea.

I end up with these 3 and just a bit of filing and tidying up to do.

Looking like a 'proper' crank assembly.

Well does it work ?

I rigged it up to a Kelly kettle and aquarium tubing and although it coughs splutters and hisses it does kind of work.

The eccentric rod has a bit too much lateral movement and the valve piston is a shade too small in diameter. the result is steam escapes past the valve as it wavers in the cylinder.

I'm going to file down the eccentric today and make a better fitting valve piston in the hope of rectifying what I think is the main issue.

I'm confident it will work though, the valve although a bit sloppy in side to side travel does seem to operate properly.

Peter.

Hi,

Thanks Brian, I had thought about trying to do a short video. At the moment I don't have a Youtube account but I'll get round the problem somehow and if necessary I open an account on youtube.

Hopefully I'll get the axle spacers and wrist pin made today and set about getting it to work.

Peter.

Hi all,

Many thanks for the positive comments received.

My postman arrived with my knurling tool and grub screws today so I'm now in a position to hopefully complete the engine.

I've never used a knurling tool before but after a quick look decided to put it to work on a few trial runs before making the bearing oil bolt.

After a few tries using different speeds and depth I ended up with this.

It looked to me worth keeping as the finished product so set about turning it to size and cutting a thread. Since I wasn't able to cut a thread right up to the head using a die I decided to turn a plain shaft slightly undersize just beneath the head. I hope this will allow it to seat flush on the housing once tightened down.

The remaining stock in the chuck came in handy to make a threaded arbour to hold the work whilst I turned it round to face off the head.

5 minutes later and a bit of filing to shorten it and this is the result.

So far so good, I reasonably happy with it.

Now I have grub screws to secure the eccentric and the flywheel I'm able to have a go completing the eccentric rod and attaching it to the valve piston.

I wasn't really sure of the best way of going about this but as a start point pushed the valve to it's furthest travel then use calipers to see how far the wrist pin will be from the main axles centre.

When the piston valve is bottoming out at it's furthest travel the wrist pin hole is nicely aligned with the end of the cylinder block as shown in the photo.

So by lining up the wrist pin hole out side the cylinder I can see where the valve ports lie in relation to the inlet when the valve is at maximum travel. The little indent I've cut next to the hole allows the main power piston to exhaust when the valve hole has slightly gone past the port linking the 2 cylinder bores. So when the valve is in this position exhaust can still occur even though the main holes are past alignment. (I think !)

One last check with the calipers tells be this is maximum travel so the 2 centres on the eccentric rod need to be just a tiny bit less than this distance to prevent the valve striking the far end of the cylinder.

Well it's drilled and filed now, I can tidy it up later once I'm happy it works.

I really hope I've done this last step correctly.

I did put a bit of wire staple in as a temporary wrist pin to give it a bit of a try blowing down the airline. Unfortunately is far too much of a loose fit for the valve to operate properly and I need to make a few spacers for the main axle to keep things in correct alignment and prevent the eccentric strap coming off the eccentric as it does now without a retaining feature on one side.

On the plus side the engine turns smoothly and the power piston does respond nicely to a puff of air.

With a bit of luck it will be finished tomorrow.

Peter.

Hi,

I'm very much a novice but can honestly say I have no problem centering in a 4 jaw independent, it's like anything if you stick at it you soon get better at it. After a 10 - 20 goes you start getting a feel for how much of a turn on the chuck key corresponds to the dial indicator reading.

One little tip I have found is that when taking work out of the 4 jaw, if the next work piece is the same diameter (or very close) then release by using only 2 adjacent jaws then when you put the next piece in simply tighten up the same 2 jaws and if you are careful you will be very close to the same centre.

In my case the chuck has a makers mark between 2 of the jaws so I just loosen and retighten the jaws either side of the mark.

Peter.

Edited By Peter Nichols on 11/07/2015 10:10:38

Hi Ian,

The problem is I drilled the holes in the plate before ordering the plinth thinking it would be wood and I'd have no trouble using 4 small brass screws. I think now the holes are too close to the edge and will risk splintering the plinth. I'm actually pleased with the plinth so don't want to damage it.

I think what I'll end up doing is to glue it down and make some dummy fittings to cover the holes - I guess it's an excuse to make a decorative brass 'handrail' round it.

There's not much I can do now till the postman brings my knurling tool and grub screws so I got thinking about how to test it once it's finished.

As it's really going to end up as a glorified ornament I'm happy just to make do with a temporary boiler just so I can say it's been tested and is a working model. Alternatively I'm looking at buying a small airbrush set up with a compressor.

For now I thought I'd have a go at rigging up a temporary boiler.

I dug out my old Kelly Kettle and camping stove and made bung to take the aquarium airline. The bung is simply a crude push in taper and the air line is only a push fit so I'm happy it's still relatively safe without a safety valve or pressure gauge.

First attempt was disappointing. Struggling to inflate a balloon and a lot of water travelling down the tubing.

I cut the tube much shorter for another go.

Looking better this time.

Anyone able to have an educated guess as to how many PSI that might be ?

Do you think it will power the engine just for a one off test ?

Peter.

Thanks Neil,

I gotta say it's been great fun building this little engine, I've never done anything like this before and have really got bitten by the bug. I'm glad it turned out ok, if it had been a disaster I'd have risked getting disheartened only a month after buying a lathe.

I'm starting now to think what to have a go at next, I'd love to tackle something bigger and a bit more sophisticated but something that's not too complex. I've considered a Stuart S50 but think it's a bit beyond my skill at the moment and I don't have a mill, though at this rate I can see me buying one before too long !

A simple beam engine also appeals to me if I can fine one that's reasonably straight forward.

Thanks John, I think that's something I need to do, when I started this project I didn't even have any parallels, it got a damn sight easier once I got myself a set.

That plinth looks tidy but its made of MDF so I don't think I'll be able to drill it and screw the brass base plate down, I've already drilled the plate so I think I'll just make some ornamental dummy fixings to sit in the holes but glue the plate down.

Anyone got any ideas what sort of glue would be best to stick brass to MDF and something to glue some of the screw threads so prevent them working loose if the base is glued down and they become inaccessible.

Thanks

Peter.

Hi,

I can't directly answer your question but this peculiarity in Australia on a similar subject may be of interest.

**LINK**

Part way down the page there are a set of facing points where 2 different gauges operate over the same track, the points divert the 2 different gauges on different routes without any moving parts.

Peter.

Hi,

The engine is nearing completion now and there isn't a lot more I can do at the moment.

I've ordered a knurling tool to make a decorative bolt for the bearing oil hole and a few assorted grub screws to secure a few components to the main axle. Until they arrive the only thing left is the eccentric rod and pin plus a few axle spacers.

I decided to tackle the eccentric rod get it filed down to size at the eccentric end then when I can secure it with a grub screw I'll work out where the hole to connect the valve piston needs drilling and file the other end accordingly.

The plan suggests making it using a rod soldered to a ring of copper pipe as the eccentric strap, I don't have any soldering equipment and thought I could make a better job by hand filing it as one piece from a piece of brass plate.

Much filing later it's starting to take shape.

One end just about done and a nice fit on the eccentric.

As it's a gift for someone I bought a decorative plinth and overall I'm pleased with how it's starting to look.

Peter.

Edited By Peter Nichols on 09/07/2015 11:10:39

Thanks Bazyle,

I started of intending to follow the plans but as I'm just starting off and have limited tool and materials I kept modifying things depending on what I have to work with.

Now the only thing that's original is the basic valve principle, everything else is 'make it up as I go along !'

Edited By Peter Nichols on 08/07/2015 16:24:07

Hi,

David, here's the website I got the full plans from :-

**LINK**

Hi,

Today I wanted to make the valve eccentric and possibly the eccentric strap (which would virtually complete the model) but was a bit unclear about the measurements for the eccentric.

I decided to tidy up the flywheel first and ask the help of others on the forum regarding the eccentric then try it after a bit of further thought and a second opinion.

The wheel I made a couple of weeks ago wasn't made for this engine and did have a lot of score marks but I thought it was repairable and the right size for this engine so I opted to try and make use of it.

I struggled to find a way of getting into the recess to take out the score marks so thought of trying with a parting tool, I know it's probably not a good way of working but there's a few thou cut will take out all the marks and I'm only moving radially about 15mm.

Fortunately it worked well, and it gave me a chance to give it a few light cuts elsewhere to true it up.

By now I'd had a bit of advice regarding the eccentric so set to work on it.

I didn't want to mess around soldering etc like the plans suggest so decided I'd sandwich the eccentric between 2 disc to keep the eccentric strap in place. This method would hopefully allow me enough width to insert a retaining grub screw that I could the use to adjust the timing.

First I turned a piece of steel to 16mm dia and drilled the hole for the main axle.

The central hole is 5.4mm in dia and the offset needed to cut the eccentric is 2.5 mm, so the new turning centre lies within the central bore.

A bit of a makeshift idea, but using a dial indicator and only loosening 2 opposing jaws on the 4 jaw chuck I was just able to move the workpiece 2.5mm in one direction only.

The resulting eccentric has the right throw (I think) but in order to turn it down to be flush with the attached disc I got a bit closer to the cental hole than I had expected.

Parting off the combined disc / eccentric.

I'm reasonably pleased with the result, on one side the 2 diameters lie flush to accept a grubscrew.

Just need to make another similar disc to go on the other side of the eccentric and trap the strap between the 2.

Peter.

Edited By Peter Nichols on 08/07/2015 15:26:15

Hi all,

Thanks for the help,it's a bit clearer now.

What I've done is made an eccentric with a 3/32 throw and a side disc to retain the eccentric strap, I'll then make another matching disc to go on the other side and sandwich the eccentric rod between the 2.

The furthest throw on the eccentric and the disc are the same overall radius to the main axle so I intend to fit a small sunken grub screw to cater for timing adjustments.

Peter.

Thanks everybody, it's reassuring to know I'm not the only one who things the drawing is wrong somewhere.

Because of the way I've adapted the engine to suit my own tools and materials rather than mess about with solder etc I'm hoping to sandwich the eccentric between 2 slightly larger discs trapping the eccentric strap between the 2. I'd like avoid having the 2 discs but cant really see a way round it.

I hope that by having one of the discs and the eccentric made from one piece it will be wide enough to allow for a small grub screw to hold it on the axle and allow for timing adjustment. It should be a simple matter to trap the other disc between the eccentric and bearing post.

Working in new money I reckon the eccentric needs a 2.5mm throw and I just need to make sure the furthest offset part of it is at the same overall radius from the axle as the outer discs so that I have the width of both parts to tap for the grub screw.

Does that make any sense ?

Peter

Edited By Peter Nichols on 08/07/2015 12:14:31

Thanks Steven,

I hope to have it finished in a few days but struggling a tad with the eccentric at the moment.

Peter

Hi all,

Can someone please help me understand a small detail in this drawing please.

I'm not from an engineering background and struggling to understand the measurements to make the eccentric on this little engine I've almost completed.

In the top left corner it shows the eccentric as being 7/16 dia, yet the measurement just to the right of the drawing looks to me as if the radius is 3/16 or is that a measurement from the edge of the bore to the edge of the work ? That to me would seem an odd measurement to include and still doesn't seem to fit with other measurements.

In the bottom right drawing it says the eccentric is 3/16 stroke am I right in saying that 3/16 is the total movement of the eccentric rod but the throw is to be 3/32 ?

I don't know what you think but to me the drawing seems a tad misleading and any help would be greatly appreciated

Many thanks

Peter.