Pipe and Bolt Engine Mod-Up

[RussellT]

Hi Steve

I feel your pain.  It is the nature of machining stuff that parts are often ruined when they're nearly finished.

As an aside I've run out of round nails - I'm trying to imagine what they'll say when I go down to the shop with a micrometer - probably something similar to what they say when you start querying the wall thickness of their pipe fittings.

I think the challenge is going to be maintaining steam (or air) tightness around the screw threads

Did I not mention that it's designed to leak and work as an air bearing as well?    More seriously that's why I chose a fine thread bolt.

Once I'd had the idea for this engine then I thought it had to be tried, but the closer that gets the more doubts I have about whether it will work.

Russell

[shipto]

Shipto, don't stop now, man.....

Was only joking I am finding it fun to work around the problems.

[vtsteam]

Hi Steve

I feel your pain.  It is the nature of machining stuff that parts are often ruined when they're nearly finished.

As an aside I've run out of round nails - I'm trying to imagine what they'll say when I go down to the shop with a micrometer - probably something similar to what they say when you start querying the wall thickness of their pipe fittings.

I think the challenge is going to be maintaining steam (or air) tightness around the screw threads

Did I not mention that it's designed to leak and work as an air bearing as well? 

I like it!!! 

You know, might not entirely be a joke -- it might just be a little faster because of it... fun not knowing what will happen in advance..!:

Shipto,   

[awemawson]

Sorry to hear of your pipe cap problems Steve. Would you not do better to use a (larger) pipe plug of the solid variety? Such as:

https://www.fastenal.com/web/products/details/4203559

Bet you wish the rules let you use a bit of iron bar

[vtsteam]

It would have been Andrew, but I didn't know it wouldn't work at the time I bought them. The earlier cap wasn't cored out the same and had enough meat. Different manufacturer, I guess.

It was borne out today -- stopped at another hardware store further out of town while stocking up on kerosene and LP gas for the storm. Bought a couple more 3/8" pipe caps, and indeed they weren't relieved behind the threaded portion.

I also wanted to get rid of chatter, and had an idea on that score. When I got home, I switched the 3 jaw spindle for my milling spindle which has a 5/8" socket and 2 set screws. Then I turned the unthreaded end of a piece of 3/8" (nominal) pipe nipple to 5/8" to fit the socket. This gave a sort of 'collet chuck" and arbor to mount the pipe cap on, with much less overhang and weight than the 3 jaw had.



The turning went really well this time -- no chatter and these newer pipe caps were nice soft grey iron -- cut like butter. So that seems to have been the problem before -- bad pipe caps -- for engine building purposes at least! I might go back and by some more of those caps next time I'm in the area. They were only $1.79 each. Cheap for a piston.

The storm has held off so far this evening, so I was able to drill the new piston for a wrist pin. I used  bit of brazing rod for that, and a few minutes ago was turning the crankshaft and watching the piston move up and down. Fun! 

[SwarfnStuff]

Hi, Just my thought on the air leakage along the thread. Would it be worth trying some of the thicker type grease, - Say that white stuff the name of which I cannot recall? Ok, it might just blow out or make the valve stiff but hey! this is an experimental job anyway, right? And, " anything you try is not a failure but just one more thing you know that doesn't work". (I think that is a misquote from the guy responsible for this -  ) A fun thread.
John B

[RussellT]

Hi John  Yes I was thinking grease might help - read on.

Steve I hope you've survived the weather.  US weather even made the TV here yesterday.

I drilled the ports today, they're still a bit undersize but I think it will work best if I open them out with a needle file when the whole engine is assembled, that way I can see how they are opening and closing.

I did make one mistake in drilling the ports which was to assume that the bolt was bottoming out in the nut (which is sealed at one end) and I'd cut the bolt to fit that length.  Unfortunately that left a gap at the bottom of the bolt so the port was too close to the end of the bolt.

I fixed it by redrilling the port further up the bolt which should be OK.  If I'd done it right I would have been able to separate the inlet and exhaust ports by a few more threads.

Anyway with the ports drilled all the moving parts are done and I was impatient to see if it would work.  So I stuck a nail (undersized) in a bit of wood and clamped the nut (bearing/cylinder support/valve mechanism) to the wood.

To start with I had no luck, but then I added a bit of grease to the threads.

Here's what happened.

Russell

[DMIOM]

      

[vtsteam]

Russell, I'm grinning ear to ear!! 

That has to be the simplest oscilating engine, ever, too! No spring, no bearing per se.

Just wonderful!! 

[dsquire]

Russell

Give the man a cigar. 
It's nice to see something different like this come together. Now we will be looking for Mk.II. 

Cheers 

Don

[vtsteam]

If I remember correctly, water pump grease used to have a fiber structure that prevented leaks as well as lubricated.

[RussellT]

Thanks Steve, Don, DMIOM

Steve, you may be grinning from ear to ear - how do you think I feel?

 

Russell

[millwright]

Well done Russel,   

 Ive been following this one and noticed very few comments from other members, but with 3277 views as i type this its proving to be a very very popular read.   loved the valve idea, saved to memory for possible future use.

John

[modeldozer]

    

Abraham

[dsquire]

WOW!

Russell. If I said that you were a happy camper I might be understateing it. 

I think maybe someone should call the Sherifs office and get a roundup going for all those emicons. 

Nice job again Russell.

Cheers 

Don

[shipto]

Well done Russellt   

[Stilldrillin]

That's a proper, happy/ smiley vid. Well done Russell! 

Is that a BGT, in the background? 

David D

[vtsteam]

Plodding along far more slowly than Russell here today -- plowed snow (though not nearly as much as anticipated) but the wind and cold temps made it very unpleasant.

This evening I did get 20 minutes in the shop. I flattened more pipe, and hacksawed and roughed it to shape as a start on the head. It will be two layers thick when done -- this one will have a hole a little larger than the bore to give a bit more clearance volume. And I think I'll just groove the top of it for a steam passage to the valve chamber.

The second piece will braze down over the first. It will be narrower to allow space for screws around the edge. That's the plan, now, anyway......

[Manxmodder]

Hi, Just my thought on the air leakage along the thread. Would it be worth trying some of the thicker type grease, - Say that white stuff the name of which I cannot recall? Ok, it might just blow out or make the valve stiff but hey! this is an experimental job anyway, right? And, " anything you try is not a failure but just one more thing you know that doesn't work". (I think that is a misquote from the guy responsible for this -  ) A fun thread.
John B

"Say that white stuff the name of which I cannot recall"

Do you mean lithium grease,or was it lard? .......OZ.

[SwarfnStuff]

Nah Manx, Lard was the water proofer on me old boots.
      Yep that was it "Lithium Grease", "told you it was white stuff" so at least I got that bit right.

     Russel, great minds and all that. Cool little job, keep it spinning. Yea 

[RussellT]

Thanks John, Abraham, Don, David D, John B, Shipto

Next job is to work out what to mount the bits to.

David D - it's a TVR Vixen - currently in bits. I took the body off at New Year so the body is alongside the chassis so I have very little space to work.  There's more pictures on a rather outdated website at http://www.hockerley.freeserve.co.uk/

Russell

[vtsteam]

Stripped the galvanizing off of some thinner tube, and flattened a piece:

[vtsteam]

I drilled and filed a hole slightly larger than the cylinder bore in the bottom head piece, then super-glued it down in correct position on the cylinder temporarily.

I then drilled the valve opening from underneath using the valve sleeve as a guide.

Then I ground a steam port between the valve hole and cylinder hole.

Finally I marked and drilled the cover screw holes through the head and into the cylinder flange, using a tap size drill for 4-40 screws. I did all this to make sure everything would line up after I brazed the second layer of the head on. It would otherwse be hard to locate the cylinder bore hole correctly once brazing was finished.

[vtsteam]

I rapped the lower head piece on edge with a hammer to shock-break the super-glue and removed the piece from the cylinder. Then filed off the glue.  Super glue can release cyanide if heated -- as when brazing, so I'm quite careful to remove it whenever I use it as a temporary clamp on metal.

Then I cut the thinner flattened sheet to rough shape with a hacksaw and filed it down until it was just a little smaller than the  bottom head piece. The small step allows easier brazing.

I clamped both clean pieces together:

[vtsteam]

And brazed: