PeterE Tries to Build a Trojan ...

[PeterE]

OK, having seen so many nice engines I got inspired to start working on the one I have had in my project box for about 10 years 

I wanted to try to build a steam engine and got the advice that this type is suitable for starters. I therefore got myself a set of Trojan Mk 1 castings. Since then I have understood that the Trojan was updated to a Mk 2 version as I found the J P Bertinat build instructions on the web some years ago. The same instructions I now use for the build.

It says to start out with the cylinder which I promptly did ...

Here it is with smooth and parallell flanges as well a a nice bore. Even the valve face got a clean-up at the same time as I needed a surface to measure from. The casting is bronze and very nice to work with.

Having come this far I saw that it is time to make the flanges round and smooth which I thought is best done in the mill. I therefore made a small "tower" to act as rotation centerfor that work. A simple piece of steel that will be mounted on the milling table.

I also made sure I have a washer as bottom "bearing" and a thicker washer to hold the complete package together.

When all fitted this is how it will look.

This setup I think will work. I aim to use a welding pliers to hold the cylinder while taking small cuts to avoid too much risk of the whole thing flipping round. I might also rig a small stop to avoid the cylinder to snap the mill if it runs away.

Please note, progress will be slow but I hope steady.

BR

/Peter

[saw]

Looks good, I will be folling your'e progress 

[krv3000]

looking good so far

[PeterE]

Thanks benni and krv.

Set it up on the mill this afternoon and fixed the flanges.

The thought-out way of doing it worked very well. I was able to feel a clear drag from the mill during climb milling so small cuts and slow work seems to be the way. You can also see the cobbled up stop block to prevent the thing to snap the mill if I lost control. That also worked good and the pip left was easy to blend out with a small file.


This way I get perfect centering of the flanges on the cylinder core. The milling threw up some burr, but nothing that was difficult to correct. Bronze is sweet to machine.

At this stage the description says that I shall mount the cylinder on an angle plate fixed to the lathe face plate as this is the common way to do it. I donīt have one of those yet so here will be the first detour in the making of the machine ...

BR

/Peter

[PeterE]

Detour done! 

Dug up an oldish angle plate casting I had. Came from College Engineering Supplies if I remeber correctly. I thought of using a piece of my large T-bar but settled for the cast iron one. I made it 90 mm long, 50 mm high, and 40 mm deep to suit the C3 face plate.

Here it is cut to size and flattened using the mill.

What size for the slots? The face plate ones are 12 mm wide which I think are too much on such a small plate so I settled for 8 mm like the T-slot width on the mill. That seemed more appropriate.

Good enough for me and it got some paint as well.

To finish this off I also made some round T-nuts to suit the plate out of a brass bar from the scrap bin and here we see all the bits.

The cylinder to the right. Yes, I did skim the face plate because it was very rough as delivered and I could not resist to fill in the circles with the shop colour ...

So all put together and the cylinder fixed so that it is perpendicular to the plate which would make the port face at right angle to the cylinder ends.

Perhaps some small counter-weight as well to make machining less jumpy.

Well, so far so good. Now back on the steam track again, but we will see for how long ...

BR

/Peter

[saw]

Good progress keep up the good work 

[doubleboost]

Looking good peter
Like you say
Some counter weights would be a good idea (change wheels work great )
Bronze is really nice to machine
Alloy bronze can be a pain to drill & tap 

[OldMetaller]

Hi Peter, I've just bought a set of castings for this engine, so I will be following your build thread with great interest!

Regards,

John.

[PeterE]

Thank you for kind words benni and rob!

John, I hope you can find some useful info, even if only to avoid my mistakes ...

Rob, Yes bronze is nice to machine and this casting also seems good to drill and tap but it is good to know that it can be a problem to take into account.

Have been occupied with the last phase of replacing the old and worn-out roof tiles on my garage/storage/hobbyarea. Found some time for metal work and thought that after this I would be ready with the main dimensions of the cylinder.

Started off well, but at the second cut the toolbit dug in into the quite soft bronze  Not a complete disaster but enough to make me re-think the setup. Obviously the cylinder had moved under load even though I tightened the screws quite hard.

In an attempt to correct the errors, I set the cylinder up using the 4-jaw instad. The jaws are big enough to grab the cylinder on the flat sides and thus keep the port face perpendicular to the lathe axis, like below.


The setup was better but I did not get it absolutely correct 

The port face is now at the correct distance from the cylinder bore when measured on the centerline which is good. The question is if I can live with the fact that the port face and then the valve "box" leans very slightly to one side. Since the centerline is OK it will not affect the centerline of the valve rod even though slightly skewed.

Well, well, I will see where this goes. In the worst case I have to get a new cylinder.

[NickG]

This will be an interesting project Peter, I often used to look at trojan castings when I was younger.

I must admit, I preferred your first setup but with another angle at the other end ... or, the same way on the milling machine but with a piece of packing under the other end.

Difficult to get things lined up in the 4 jaw like that and the chances are you'll leave big marks from the chuck jaws in the gun metal.

Nick

[PeterE]

Hi Nick,

The Trojan is supposed to be easy and as far as I see it will not be difficult by being complicated, just that I am still not very much experienced with metal machines and different materials. I hope it will turn out good in the end.

I have actually seen both setups, the angle plate on the face plate, as well as the 4-jaw setup. I have tried both and the first time I used the 4-jaw it just came out good. The risk of marking the faces with the chuck jaws is of course present, but I donīt force the jaw screws that much nowadays as I did in the beginning, it works well anyway.

Using two angle plates on the face plate like a vice-type setup would of course be even more rigid.

Doing it in the mill instead would probably be just as good. I will use that kind of setup when milling the ports so then we will see where it goes.

Time to read the next section and proceed with the machining ...

BR

/Peter

[Rob.Wilson]

Following along Peter 

Looks like your making good steady progress 


Rob

[PeterE]

Good and steady progress, well I do not know really, I definately feel like a beginner with this.

First I made the top end cap from the supplied casting. It had a cast-in spigot so it could be gripped in the chuck and that way the "inside" towards the cylinder bore was made. Carefully approaching the fit diameter of the cylinder I succeeded to achieve an easy fit without slop. 

Turned the cap round to remove the spigot and take down the thickness to drawing measure. Succeeded with this as well but "re-designed" the cap to become domed instead of just "cut off". Worked out fine so far. 


Then marked out for the six fasteners and now I got into problems. The marking out was OK but after drilling the first guidance holes, one of them was misplaced as the tip of the drill decided to walk outside of the punch mark  OK It was a pilot hole and as this is the first engine I can live with it  When then trying to chamfer the holes using a countersink bit, the bit grabbed the cap and threw it out from my vice = one hole destroyed 

Heavy sigh,  if I shall save this I have to think a bit.  Will be back on this. Perhapsd I decide to redo the cap as I have a 10 mm thick brass flat bar.

Well I turned my attention to the bottom cap instead. It also had a cast-in spigot to use, which I did. The same first stage went fine and I managed to achieve the same nice fit in the cylinder with this cap. When it all was set up I drilled all the way through for the piston with a 4 mm drill. Now the casting is made for the bottom cap Mk 1 which means that it is necessary to remove some of the casting to make room for the Mk 2 piston guide (tube). Also this went fine even if it was thight for space.

I made use of my newly made tailstock support using the smallest center in the 4 mm hole, worked well. I also found that well sharpened and honed HSS tools were actually better for this soft gunmetal than the usual triangular carbide inserts. It should probably be those aluminium tips instead, they look sharper than the ordinary CCMT bits.

Anyway, it went fine and I could come to measure and cut off the spigot as intended. Time to open up the 4 mm hole to 5 mm to make the packing gland nut thread. As I work in metric I went for M6x1 which was OK up to the point where I tried a screw for fit, new disaster 
It turned out that the cap had tipped in the vice when opening up the 4 mm hole and becoming angled instead if straight along the center axis. I did do the other holes in the bottom cap and they went fine all of them.

So, after today I have two half-ruined bits 


Now I am thinking of how to save these errors so I donīt have to get new bits.    I can of course make plugs from the left over spigots and solder them into the respective holes and then re-drill and tap as required, but I am not sure this is the best way forward.

BR

/Peter

[saw]

Peter, wellcome to my world. I have done this a couple of times and it is not so fun, but the fun part is to calcylate how to cheat it together so it looks really out.
If I was you, I would use my lathe and turn some piceses that fits that holes and solder them together, and then do a fresh start.
About the bottom cap, why diden't you use youre lathe to drill the hole. If you set it up correctly you are garanti that the hole and the threading will be in the correct line
Otherwize I think that you are doing well. 

[PeterE]

Hi Saw/Benni,

Thanks for comforting words, I guess I am not the first to goof it. When it comes to the holes in the top cap it is really a question of whether I want to keep the gun metal casting or make a new cap from brass. If I decide to keep the gunmetal one, I will go the way you describe by making plugs and solder them in place.

The bottom one is trickier actually as the supportive spigot is not possible to use as this is where the hole and thread shall be placed. My first thought is to use one of the left-over spigots and turn a short piece of spigot and thread with M6 and solder it in place. Then re-drill the 4 mm hole properly in line and then in some way try to turn the cap and open up and thread again.  Another way to do it is to set it up in the lathe and open the bad hole to a plain 6 mm hole for threading using a "french" M7x1 thread instead. This is for the gland nut so it is a one-off anyway and the odd thread does not matter.

Coming to think about threads, All the drawings state imperial ME threads typically 1/4"-40. Normally I would happily translate them into metric, but a -40 thread would translate into 0,5 mm which is not a common one = expensive. Just because of that I wonder if I shall go for the stated ME threads instead?

BR

/Peter

[saw]

PeterE, my advize is, don't change to 6mm becource it's coarse thread. Stick with 1/4-40". The threading is more nicer and fine threaded.
You can find tap and die on eBay for a cheap money. 

[PeterE]

Benni,

I guess your'e right about staying with the imperial threads due to the small thread.

ebay you say, do you know any company selling good stuff preferable HSS through ebay? Otherwise I am looking for a set with the ME-taps and dies but WITHOUT the wrenches and handles as I already got more of those than I use in both metric and imperial dimensions.

BR

/Peter

[saw]

PeterE.
There are lots of good company selling dies and taps, but I usualy buy from RDGTOOLS becource I think they are very greate. When you shell buy taps, try to find a set for t ex 1/4-40, with that I mean one for tap, one middle tap and one finish tap. That will give you the very best result.
Be also very carefull when you are drilling the hole for threading so you drill the right size of the hole. 

[PeterE]

Hi again Benni,

Thanks a lot! I will look into your suggestions. I usually make a group of the taps, the die and the appropriate core drill for each. It is easier to find them that way.

BR

/Peter

[Jasonb]

You may also want to think about using M6x0.75, this is the metric fine range and is used on quite a lot of European made steam fittings if you should ever have a need to buy them you will then have suitable taps & dies.

It also means you can still use standard 6mm diameter materials, if you go to ME threads then you will also need 1/4" round stock.

Also when you come to redrill the gland hold the work in the 4-jaw so it will stay true.

J

[PeterE]

You may also want to think about using M6x0.75, this is the metric fine range and is used on quite a lot of European made steam fittings if you should ever have a need to buy them you will then have suitable taps & dies.

It also means you can still use standard 6mm diameter materials, if you go to ME threads then you will also need 1/4" round stock.

Also when you come to redrill the gland hold the work in the 4-jaw so it will stay true.

J

Hi Jason,

Thanks for the info, very good! I actually do have an M6x0,75 tap and die but only the first, I need to add the second and bottom taps to complete the set. 

I was also a bit surprised to hear that there are steam fittings in metric, havenīt heard that before. Must google that.

Yes, I will cobble something up so I can hold the cap properly in the 4-jaw for correcting the gland goof.

By the way, is soft soldering enough or should I go for silver solder?

BR

/Peter

[saw]

By the way, is soft soldering enough or should I go for silver solder
You have to go with silver solder. 

[PeterE]

OK, good to know. Time to revive my silver soldering skills.

BR

/Peter

[Jasonb]

If you are only going to run on air then soft solder would do, silver would be advisable for steam.

I'll dig out. Link for the steam fittings when i'm on my other computer tomorrow.

J

[PeterE]

Hi Jason,

OK, I guess that the steam temp will be high enough to challenge the soft solder joints. I think I will go for silver soldering anyway. 

BR

/Peter