Bob J's No.21 Steam Engine (drawings and STP files by Pat J)

[a41capt]

I don't know the technical properties of PETG and PLA...?
But this would probably run of 2psi of steam, too? - Providing piston and cylinder are the same material (for expansion).
K

PLA isn’t very heat resistant, and prone to deformation at temps around 120 F. PETG is more heat resistant and I use it for applications where the item might see higher temps. Living in Arizona, summer temps (especially in a vehicle) get to extremes and tend to melt PLA where PETG weathers the storm.

I have considered live steam for a PETG model, perhaps even a PETG/carbon fiber IC model with some metal components since I’ve been successfully printing spur gears for a couple years now.

John W

 

[bobcjohn]

That's impressive at 2psi. Very nice-looking engine and prints. Definitely a smooth runner. My engines made of aluminum brass and steel need 5-10psi.

I'm really new to this 3Dprinting. The white filament I used is called poly cast. It's supposed to burn out clean for investment casting. However, I have had very little luck with that process. The finish on this project wasn't all that good, not near as nice that in your video. The filament I used for the base (gray) was much better, but on the smaller parts it had trouble sticking to the printer bed.

Bob

 

[a41capt]

That's impressive at 2psi. Very nice-looking engine and prints. Definitely a smooth runner. My engines made of aluminum brass and steel need 5-10psi.

I'm really new to this 3Dprinting. The white filament I used is called poly cast. It's supposed to burn out clean for investment casting. However, I have had very little luck with that process. The finish on this project wasn't all that good, not near as nice that in your video. The filament I used for the base (gray) was much better, but on the smaller parts it had trouble sticking to the printer bed.

Bob

Bob,
Depending on your printer and print bed, a good washing with dawn dish detergent and a follow up coat of Elmer’s glue stick on the print bed usually takes care of getting the filament to stick.

A bit of time spent with calibration (temperature tower, pressure advance, flow rate, and retract setting) makes a huge difference in consistency and finish. Loads of info specific to your printer on “The Tube”.

John W

 

[GreenTwin]

The Prusa XL has a multi part bed heating system, and that has eliminated all bed lifting, at least with PLA.
It won't lift even with a 14 inch wide print.

Adjusted the thickness of the first layer is important to minimize bed lifting.
The XL self-adjusts the first layer, and I think that is part of the secret of its excellent bed adhesion.
It is nice to not have to do that.
.

 

[rosveld11]

Hallo there,
I found these on the net and planning to start making in the near future, the drawing is in metric made by J. de Waal, he has got a ton of all kind engines, they are free for download and personal use only, I got the drawings via Pinterest.

 

[Richard Hed]

Hallo there,
I found these on the net and planning to start making in the near future, the drawing is in metric made by J. de Waal, he has got a ton of all kind engines, they are free for download and personal use only, I got the drawings via Pinterest.

That's a nice beginning. What kind of equipment do you have? There are several peeps on this forum in Nederland whom you might be able to meet in person.

 

[GreenTwin]

J. de Waal has redrawn several of my drawings to put them into his format, and make them metric.
I don't care for the holes in the flywheel that he sometimes adds, but I am sure many like that sort of thing.
I don't like his extremely crowded drawing format either, but others like that too.

I sent de Waal an email and asked him to please stop copying my drawings, and make his own drawings and engines.
I have not seen him copy any of my material since I sent that email (about a year ago), so perhaps he will stop.

de Waal has a big following in the hobby community, and I respect that, but a lot of it is not his original material, but rather drawings that someone else has gone to great lengths to produce.
There are many models on Grabcad that were built using de Waal's drawings, but actually they are drawings de Waal got from me.
The problem is that the credit always goes to de Waal, as if he had created the drawings originally.
So whether intentional or not, de Waal coop's my drawings and designs for his own purposes.

I am ignoring what de Waal has copied to date as far as my drawings, but he should not use any more of my drawings, since I have a copyright on my drawings that states "for non-commercial use only", and he advertises his drafting service on his drawings which he creates from mine, which is a commercial purpose, and a direct violation of my copyright.

The "designer drafter unknown" on his drawings would be me.
It is very disturbing for me to go to Grabcad, type in "steam engine", and see so many of my engine designs attributed to de Waal; its just not right.

.

 

[rosveld11]

That's a nice beginning. What kind of equipment do you have? There are several peeps on this forum in Nederland whom you might be able to meet in person.

Hello Richard,
I've got 2 bandsaws 1 benchsaw for metal, 1 for wood, a Sixis milling machine I converted to dual CNC/Manual operation and a Lantain metal lathe plus a Snapmaker A350 3D printer, I use Tinkercad a lot.

 

[Maxjon]

Hello Richard,
I've got 2 bandsaws 1 benchsaw for metal, 1 for wood, a Sixis milling machine I converted to dual CNC/Manual operation and a Lantain metal lathe plus a Snapmaker A350 3D printer, I use Tinkercad a lot.

How do you find Tinkercad? I've been using it with limited success. Its a bit more user versatile than the Prusa Slicer when scratch designing.

 

[rosveld11]

How do you find Tinkercad? I've been using it with limited success. Its a bit more user versatile than the Prusa Slicer when scratch designing.

I use Tinkercad often for modifying or making new parts, specially adding holes for tread inserts.
Kind regards

 

[salmonr]

Hi All, I'm part way through this little engine and would like some advice. I am new to steam engines and on completion,I would like to run it off a small compressor. I see the gland nut on the cylinder has a .257" clearance dia on a .250 con rod . Would I need to put some kind of gasket in between the gland nut and cylinder head to compress upon the conrod slightly.As I say, I'm new to this. It just seems there would be a lot of air leakage between the two, and I'm not sure how they work.Thanks. Rob.

 

[Steamchick]

The gland is typically graphited string. A couple of turns, then compressed by the gland nut, causes the string to provide adequate sealing with the graphited string allowing the low friction to permit the rod to slide through.
The modern alternative is PTFE. You can make or buy seals.Or wrap PTFE "Plumbers thread seal" tape, twisted and wrapped instead of the graphited string. Or an O-ring, but you really need maybe a polyurethane or Viton O- ring for low friction. Anyway it will need oiling, and when the engine is in steam, the steam oil should maintain adequate lubrication. If using compressed air, the "compressed air-tool oiler" should similarly provide adequate lube. But a bit of Molybdenum or Lithium grease on assembly helps, until the oil gets through..
Hope that is useful?
K2

 

[Richard Hed]

Hi All, I'm part way through this little engine and would like some advice. I am new to steam engines and on completion,I would like to run it off a small compressor. I see the gland nut on the cylinder has a .257" clearance dia on a .250 con rod . Would I need to put some kind of gasket in between the gland nut and cylinder head to compress upon the conrod slightly.As I say, I'm new to this. It just seems there would be a lot of air leakage between the two, and I'm not sure how they work.Thanks. Rob.

That seems like an awful lot of clearance. .007 is a huge amount. Is that what the drawing says? I would try for a mere .001 and if that is not enough, then enlarge it with a toothpick but start small and add titbits at a time. what is the conrod made from? steel or something else?

 

[Steamchick]

If I understand correctly, we are discussing the oscillating engine with drawings in post#45.
One disadvantage of these engines is that the rod guide bearing is also the gland nut, and alignment isn't always perfect due to the thread and end plate alignment..
When in operation, the side thrust to develop the oscillation deriving from the crank throw, exerts a side-thrust on the gland/ rod bearing. First one side, then the other. Imprecisely aligned threads cause binding, and wear. Some designs utilise a large clearance so the engine is made and works, but the side thrust generating the oscillation is applied to the gland material. This material may wear rapidly, but if graphited string is cheap and easy to replace. Maybe that was the Designer's reasoning?
If parts become worn, or bind, when smaller cleanses are made, but the thread alignment or something causes bad alignment, the brass can be tinned with tin-lead soft solder and re-bored, when the solder will take-up some of the wear.
I have bought worn engines for refurbishing! Not all things appear to have been well made!
K2

 

[TrollForge]

J. de Waal has redrawn several of my drawings to put them into his format, and make them metric.
I don't care for the holes in the flywheel that he sometimes adds, but I am sure many like that sort of thing.
I don't like his extremely crowded drawing format either, but others like that too.

This begs the question, (and I am still just learning to navigate this site, so I hope it is not a stupid question.)
Is there somewhere where we can go to look at / acquire your drawings?
And would you consider videoing for YouTube Commercial Use? (considering I only make about $37/month CDN. from YouTube...)

 

[GreenTwin]

The gland is typically graphited string. A couple of turns, then compressed by the gland nut, causes the string to provide adequate sealing with the graphited string allowing the low friction to permit the rod to slide through.
The modern alternative is PTFE. You can make or buy seals.Or wrap PTFE "Plumbers thread seal" tape, twisted and wrapped instead of the graphited string. Or an O-ring, but you really need maybe a polyurethane or Viton O- ring for low friction. Anyway it will need oiling, and when the engine is in steam, the steam oil should maintain adequate lubrication. If using compressed air, the "compressed air-tool oiler" should similarly provide adequate lube. But a bit of Molybdenum or Lithium grease on assembly helps, until the oil gets through..
Hope that is useful?
K2

Steamchick is correct, the gland needs a bit of packing material, which is graphited string, or even grease on a string.
I am not into using o-rings for steam, due to the heat that can be involved, and since old steam engines did not use o-rings.
Wrap the string in the same direction that the gland nut rotates to tighten.
If you get the gland too tight, the engine won't run, and if you get the gland too loose, it will leak, so you need to find that just-right point.

.

 

[GreenTwin]

This begs the question, (and I am still just learning to navigate this site, so I hope it is not a stupid question.)
Is there somewhere where we can go to look at / acquire your drawings?
And would you consider videoing for YouTube Commercial Use? (considering I only make about $37/month CDN. from YouTube...)

If you go to the "Building Them - Plans" section, go to "filter" on upper right, type in "greentwin", under "started by", hit the "filter" button, and you will seen the plans I have posted on this site, which are for the Dake, Bernay, Greentwin, and BobJ's No.21.

I don't do anything commercial; all of the drawings I have uploaded are open-source for non-commercial use only.

I stopped uploading drawing sets because some folks were abusing that and using the drawings for their commercial use.

Pat J.
.

 

[GreenTwin]

Here are direct links to the Greentwin, Dake, and Bernay drawings:

https://www.homemodelenginemachinis...green-twin-oscillator-drawings-by-patj.34341/

https://www.homemodelenginemachinist.com/threads/dake-engine-drawings-by-pat-j.34331/

https://www.homemodelenginemachinist.com/threads/bob-js-bernay-steam-engine-drawings-by-pat-j.34339/

.

 

[salmonr]

The gland is typically graphited string. A couple of turns, then compressed by the gland nut, causes the string to provide adequate sealing with the graphited string allowing the low friction to permit the rod to slide through.
The modern alternative is PTFE. You can make or buy seals.Or wrap PTFE "Plumbers thread seal" tape, twisted and wrapped instead of the graphited string. Or an O-ring, but you really need maybe a polyurethane or Viton O- ring for low friction. Anyway it will need oiling, and when the engine is in steam, the steam oil should maintain adequate lubrication. If using compressed air, the "compressed air-tool oiler" should similarly provide adequate lube. But a bit of Molybdenum or Lithium grease on assembly helps, until the oil gets through..
Hope that is useful?
K2

Thanks for the info, just one question, when you say steam oil , do steam engines have an oil mixed to steam ?, or does the steam just pick up oil that is lubricating.

 

[salmonr]

Steamchick is correct, the gland needs a bit of packing material, which is graphited string, or even grease on a string.
I am not into using o-rings for steam, due to the heat that can be involved, and since old steam engines did not use o-rings.
Wrap the string in the same direction that the gland nut rotates to tighten.
If you get the gland too tight, the engine won't run, and if you get the gland too loose, it will leak, so you need to find that just-right point.

.

Many thanks