Member postings for Brian John

1. The drain on the lubricator is threaded.

2. I am also puzzled about another point : before I installed the manifold connecting the two cylinders I was running the engine in by connecting the air hose to one cylinder at a time. After turning the compressor off the engine would continue to run for about 16 revolutions. But now that I have connected both cylinders the engine will only run for about 5 revolutions.

Does this indicate that I have not got both cylinders synchronised with each other or is there too much leakage around all the new pipe work ?

I have been delayed due to a family illness but I have finally had a go at finishing this 7BIM engine by adding the manifold, displacement lubricator and a globe valve. There is still some leaking of air around the tube union on the manifold. I will have another look at this tomorrow. I may have to use some sealant (Loctite 567)

I am also puzzled why there is some air leakage from the bottom of the displacement lubricator ? Note that there is no oil in it now as I am not running it on steam yet.

Edited By Brian John on 11/10/2014 04:27:12

Has anybody tried one of these compressors for running steam engines ? I would like to know how quiet they are. My current compressor is far too noisy and gets hot after only 20 minutes.

**LINK**

I live in Australia but I would imagine that these are available in the UK .

I have tried aquarium pumps but they are useless.

Edited By Brian John on 10/10/2014 06:04:33

Edited By Brian John on 10/10/2014 06:04:53

Yes, I am just using a cordless screwdriver to drill the holes.

I need a washer (or something) with a small hole : this will help me to find the centre next time. I will rummage in the nuts and bolts box.

I am in the process of fitting a displacement lubricator to my newly built 7BIM engine but I realised that I did not order enough Tee fittings on my last order to PM Research. I did have a tree casting though so I decided to give this a go. There are two Tees on the tree.

**LINK**

I want to end up with this :

**LINK**

Easier said then done ! I managed to end up with two Tees but they are not very neat so a bit of information might help next time.

1. I cut them off the tree using a Dremel tool. What would you have used ?

2. I marked the centres with a centre punch. I did it by eye but is there a more accurate way to find the centre ?

3. I then used a centre drill but I found that I was never quite in the centre ! I think my centre punch mark was slightly out but at this stage I do not think there is any way to fix this...or is there ?

4. I drilled out the fitting with a 4mm drill. Charts on the internet show this is the correct tap drill for 3/16-40 ME. I did this with a hand drill. The big problem here is holding the fitting in a vice without damaging it. I was using aluminium soft jaws but these can still squash the fitting out of shape. Any suggestions to solve this problem ?

5. I then used carbon steel taps to cut the thread : taper tap then plug tap...no second tap. Some of them turned out okay but others were not quite square. Is there a ''bodge'' to fix this once you have already cut the thread ?

I realise that practice makes perfect but the next time I do this procedure I want to get a better end result. What I have ended up with is useable but you would not take a photo of it to put in a text book !

Edited By Brian John on 14/09/2014 04:37:39

Edited By Brian John on 14/09/2014 05:03:47

Okay, all problems have now been solved and the 7BIM runs as nicely as the single cylinder 3BIM. Getting the piston rods set at the correct position in the cylinders is crucial on these. Loctite 222 was used on the screws passing through the connecting rods to the cranks ; other wise one side will work loose and the other side will tighten up. I also used Loctite 567 thread sealant to stop the packing nuts from working loose.

I still have to put in the manifold connecting the two cylinders and then add a displacement lubricator.

1. So you do not have to scrub the parts... you just put them in the pickle and if the solution is strong enough then they will come up shiny ?

2. Yes, I was wondering about white vinegar too ? It would be much safer and easier to obtain than sulphuric acid and much easier to use than citric acid.

Edited By Brian John on 12/09/2014 04:57:15

What about Delrin or some of the other modern plastics ? They would be less likely to break upon fitting.

Edited By Brian John on 11/09/2014 18:12:53

What do you make piston rings out of ?

1. Is it possible to make your own piston rings ?

2. How necessary are they ? What if you did not use any rings or Teflon packing at all ?

I will be having a go at hard soldering a small boiler soon. I have bought some citric acid from the supermarket (75 grams). How concentrated should I make the pickle to neutralise the flux ?

The second damaged Sieg C0 was sent back today so I am still looking for a small lathe. Does anybody own a Proxxon FD 150/E ? It has a 55mm swing. Does this mean the maximum flywheel it can turn is 55mm or 110 mm ? Is there a face plate that can be bought to go with this lathe ? It does not look like it but I find that unusual.

**LINK**

I think this will be too small for building stationary steam engines but I am running out of options.

NOTE : I live in Australia

UPDATE : The piston and the rod are still turning hence everything is getting out of synch. I will have to tighten the locking nut on the piston rod against the cross head to stop this happening. I did have it tightened at the other end of the thread to make it easier to adjust the length of the piston rod. (Two nuts and a slightly longer thread would be more useful here.) I am surprised that there is so much movement. The single cylinder 3BIM does not have this problem.

Try again tomorrow !

I am still having problems with the RH cylinder : it runs for about 10 minutes then gets slower and slower and stops. Yet both the left and right side have been set up the same in terms of valve and piston settings. I am really puzzled at this.

Edited By Brian John on 08/09/2014 06:50:39

If the drawings of a steam engine called for a 1/2 inch stainless steel piston would you order 1/2 inch bar stock or 9/16 inch and turn it down ?

Edited By Brian John on 06/09/2014 17:56:29

UPDATE : using Loctite on the piston nut did not help but it does not hurt either. Now I will not have to worry about this nut coming loose. I found that the binding only occurred under pressure and when I disconnected the air hose and turn the flywheel by hand the engine gradually loosened up. This indicated a problem with my valve settings. I found that the valve on the RH cylinder was not centred so I unscrewed it from the eccentric one full turn and this seems to have solved the major problem.

1. The RH cylinder is still giving a few problems : it requires about twice as much pressure (about 5 PSI) as the LH cylinder and even then it runs much slower. There is also a knock which I cannot locate. Any suggestions there ?

2. I also removed the gland packing as a possible source of friction and I have found that it makes no difference to the running of the engine. What is the point of it ?

Edited By Brian John on 06/09/2014 05:29:51

Edited By Brian John on 06/09/2014 05:31:28

I have turned the crossheads over and it did not work ; the engine is still binding. I think the only thing left to try is the Loctite on the piston nut.

NOTE : I think I could disassemble and assemble this engine in the dark now !

Edited By Brian John on 04/09/2014 05:21:59

1. The cylinders are brass and the pistons are stainless steel. Nothing is running long enough to get hot ; the different expansion rates will not be the problem. The 3BIM engine runs well.

2. The crossheads move freely without the pistons attached.

3. I will try flipping the crossheads over tomorrow but as these are probably machined in bulk I do not think they will be out of alignment. At this stage I will try anything !

4. I will disconnect one piston/cylinder and just concentrate on getting the other side to run without any problems.

Edited By Brian John on 03/09/2014 18:11:24

No, it is mechanical binding. When I release the nuts at either end of the piston rods then things start moving again. I do not understand this at all. There is enough lubrication.

I might try loosening the piston rod nuts and holding them in place with Loctite and see how this goes ie. I will not tighten the nuts against the crosshead and the piston. I will leave some play there.

NOTE : these piston rod nuts control the stroke of the piston. It is how the piston is centred in the cylinder.

Edited By Brian John on 03/09/2014 14:29:22

I am building the 7BIM double piston engine by PM Research. The two cylinders are not yet connected with a manifold ; I am running each cylinder on air to test them. I can get them running nicely for about 15 minutes but then they start binding up...usually at BDC.

**LINK**

I think the clue lies in step 4 of the instructions :

''Adjust piston rods in crossheads until piston strokes are centred in cylinders. Torque screws evenly to prevent pistons from binding.''

How does the reciprocating motion of the piston cause a torsional force ? If I can understand what is happening then I can work out a way to prevent it.

NOTE : I have already built the single cylinder 3BIM but this must have been a fluke as it runs perfectly !