Trivet Engine?

[Tony Bird]

Hi,

I haven't had time to go out and visit charity shops for something to make a cylinder from. It is more likely that I will come across something suitable when I am not looking for it.

I thought the model would look more balanced if it had a pulley on both sides of it so I used the part of the pipe joint that had been turned to check the thickness the joint could be made to make one.

Another clock case door was sacrificed.











Regards Tony.

 

[Cymro77]

Tony,
Again you amaze me - such imagination. I just can't wait to see the final results. I am sure they will be quite audacious! Thanks for sharing, I will be following.

 

[Tony Bird]

Hi,

I haven't so far found anything to make a cylinder from I think it is unlikely this side of Christmas. However while it town I visited a second hand/antique shop and spent £2 on a brass castor.



The castor was taken apart and cleaned up. The wheel is 40 mm in diameter and will make a pulley with very little effort and I am sure the clevis will come in useful to.



The hole in the wheel has been trued and made 3/16" in diameter and a grub screw fitted.



There is no use for either part at the moment so it has only been painted with etching primer.

Regards Tony.

 

[Foozer]

Sticking my chin out to get a tap - Just can't get the eye from focusing upon the beam of first impression - The utilitarian shape seems out of place. All the other pieces flow like music and then it's that flat note of the beam . . .

 

[Tony Bird]

Hi,

Sticking my chin out to get a tap - Just can't get the eye from focusing upon the beam of first impression - The utilitarian shape seems out of place. All the other pieces flow like music and then it's that flat note of the beam . . .

Yes it would be good to find a serpentine piece of brass to replace the pair of knives as the beam, which I think/hope will look better painted green. Using the knives allows me to position the connect rod and piston rod. Maybe something will turn up but finding something to make a cylinder from would be nice to.

Regards Tony.

 

[Cymro77]

Methinks I need to check out more thrift shops here in USA! Yet another cool find Tony I know you will find a use for it.

 

[Tony Bird]

Hi,

Still no luck with anything to make a cylinder out of. I took SWMBO into town to get the bus to London to visit the latest granddaughter for a few days. On my way home I visited a couple of charity shops and might have found the connecting rod at a cost of £0.25 I can just afford not to use it.

I think it is a candle snuffer.



Taken apart.



Fitted; it is too long but could easily be shortened.



Regards Tony.

 

[Tony Bird]

Hi,

The candle snuffer handle has been used for a connecting rod. It looks a bit heavy; but is screwed in place so can easily be replaced if something better comes along. Having a connecting rod allows a big end to be made.

Drawing? And a roughed out piece of rectangular brass block.



Drilling securing screws in the block.



Splinting block using a parting tool.



Both parts of big end screwed together and crank centre centre drilled.



Big end drilled, reamed and shouldered.



Centre for connecting rod.



Hole drilled and tapped for connecting rod and a shoulder turned.



Finished big end.



Big end on axle.



Connecting rod fitted.




Regards Tony.

 

[Cymro77]

Tony.
Fascinating! One question why did you use parting tool to split the big end block? Wouldn't a saw have worked better? Thanks for sharing.

 

[Tony Bird]

Hi David,

The block was already set up in the lathe so it was split by parting. It could had been sawn but in either case the faces would need machining so they mated.

I worked on making a crank shaft today. As most of the model is brass I decided to make the crank webs from brass.

First the section of the axle to be removed was partially cut through.



Then a piece of brass that has had a previous use was cut into make the crank webs.



The pieces cut were machined to the same size using a shellac chuck.




The machined pieces were drilled while together for the axle and crank pin. then Loctited and pined to them to make the crank shaft.



Shoulders were turned on the crank webs.



Using the previously sawn slots part of the axle was removed.




The model except for the beam which has been painted was assembled.




Assuming the paint on the beam dries hard enough overnight I can check if everything still lines up tomorrow.

Regards Tony.

 

[Tony Bird]

Hi,

Today the engine was assembled as far as it has progressed; before the now painted beam was fitted the connecting rod was finished by making and fitting a oil pot to the big end.



Because the beam has no counter balance as a conventional beam engine does the flywheel was lightened by drilling holes in line with the crank throw to make it a bit more in balance..



The big end and crank.



As the assembled engine looks.




I think the paint has improved the look of the beam.

Regards Tony.

 

[Tony Bird]

Hi,

A short video of the engine so far being turned over by hand.

https://youtu.be/X3F5T10Ns68


Regards Tony.

 

[Cymro77]

Tony,
You make it look so easy! I am glued to the computer screen waiting for the next episode! The little video also shows the potential of this creation.
Thanks for sharing, David

 

[Tony Bird]

Hi,

As yet nothing has been found to make a cylinder out of and nothing is likely to come up until the New Year. The beam its connecting rod and the crank throw are quite heavy and I was wondering how this would effect the engine's performance especially at low speed. So I decided to try and balance out these weights by reducing the weight on one side of the flywheel and adding weight to the other. First more holes were drilled in the rim of the flywheel and a counter balance to the other.



The counter balance is removable but will be painted if it is found necessary.

The brass sides were cut from the remaining clock case back



And to add weight a piece of lead was put between the spokes.



The engines assembled.



Have a Great Christmas and a Healthy New Year.

Regards Tony.

 

[Tony Bird]

Hi,

I did a bit of work on the Trivet engine today making the eccentric and a cylinder support. I hope the photographs show how they were made. Starting with the eccentric sheath made from hex brass.







The cylinder support is made from some brass'T' section with an extra piece of brass hard soldered to the vertical part.



The eccentric itself is made from some recycled steel; a half shaft I think.





As the engine looks to date.




Regards Tony.

 

[Cymro77]

Tony,
It is slowly getting there. I hope you find that cylinder material soon!
Once again thanks for the machining instruction. I had never thought of making the eccentric with hex material.
DW

 

[Tony Bird]

Hi David,

I had never thought of making the eccentric with hex material.


I often use hexagonal brass rod to make eccentrics but up until now after drilling any holes required I have always turned them round. I just thought the eccentric would look a little different being left hexagonal.

I have now gone as far as I can without starting on the cylinder. The piston stroke is 50 mm so I will need something about 65/70 mm to make a cylinder. But if nothing turns up I will fabricate a cylinder. Today I made an oscillating valve to fit to the cylinder support. This required a bit of a drawing, so having found the pencil case, I came up with the following.



The valve has an minimum operating angle of 34 degrees, which the eccentric should manage OK.

I had intended to use a 4 oz. brass weight to make the valve.



Then a bit of a disaster the brass was only a case it was lead filled! You would never have guessed just looking at it.



Found another piece of new brass and made the valve. The steam slots were milled using a rotary table. The cylinder support has been drilled with steam passageways.



This is as far as I can get without a cylinder.



I suspect fabrication will be the way to go, I cannot even think of something that could be used to make a cylinder from, it really needs to be brass.

Regards Tony.

 

[ShopShoe]

Tony,

Perhaps an old table lamp or light fixture. I got some good solid brass from a 1930-era desk lamp that was mostly brass, but painted over.

Or perhaps brass or bronze from an old faucet or valve.

--ShopShoe

 

[Tony Bird]

Hi ShopShoe,

Many thanks for the ideas but I have done a few sketches of the overall size of a cylinder that could be used on the Trivet engine, having done some sums the largest realistic bore can only be 12 mm ( 1/2") the stroke of 50 mm is already set. So the engine will be 50 mm stroke with a 12 mm bore (2"x 1/2"). I have decided to go along the fabricated cylinder route. There are a couple of reasons one I don't think that it is likely that something 65/70 mm long suitable for a cylinder will be found in the near future and in a few weeks we take our annual Winter break and when we return I have several projects for other people to do.

So this morning while cogitating about the cylinder I made the fulcrum pin/bearing for the oscillating valve. It uses a small brass wing nut that has been in my assorted nut and bolt box for as long as I can remember. I knew there would be a use for it. The spot marks on the support signify when the valve is closed centre and the outer the minimum movement for the valve to be fully open in each direction.



Having decide on the fabricated route I checked on what materials I had to make the cylinder with. I came up with a piece of thick wall brass tube for the cylinder itself and some hexagonal brass for the other bits of the cylinder.



It was a bit disappointing to find that the bore of the tube was a little over 1/2" in diameter however it was a bonus! A piece of K&S brass tube with an ID of 1/2" is a slide fit in the bore so it could be used as a liner. So it saves having to get a good finish on a long 1/2" bore and my 1/2" reamer is getting to the end of its life. I even managed to find a 1/2" '0' ring.



So it is pencil sharpening time to see what can be done with the materials available.

Regards Tony.

 

[Tony Bird]

Hi,

Having made the decision to fabricate the cylinder I retired to the drawing office for a bit.



Having made a working drawing it was back to the workshop to cut metal first the hexagonal rod was cut to length.



The the ends of the hexagonal rod were faced to length before centre drilling followed by a 18 mm drill.




The short length of remaining hexagonal rod received similar treatment but a smaller size hole which was also bored and made round before parting off and faced.





Little had to be done to the cylinder tube just cut it to length and shoulder its ends to take the brass washers previously made.



The brass washes were hard soldered to the tube.



After an afternoons work we have a brass bobbin and a hexagonal rod with a hole through it.



Regards Tony.