Benson inverted steam engine

[crueby]

Thing of beauty - looks like one of the old Victorian era scientific instruments, wonderful job!

[Dave Otto]

Very nice George!

Dave

[gbritnell]

The drawings call for a pair of identical size helical gears which means the governor runs a crank speed. The charm of these engines and most steam engines for that matter is their slow operational speed. I have looked at the Youtube videos of the Benson and even when the speed is increased the governor doesn't have much action so I decided to try and speed up the governor by making the ratio a little different than 1:1. Using the spreadsheets provided by Don I was able to keep plugging numbers in until I got something that would satisfy the center spacing. I started with the tooth count that seemed appropriate then kept changing the diametral pitch and adjusting the tooth count until I hit the center distance by .002. I ended up with a D.P. of 64, tooth counts of 17 on the crankshaft and 13 on the governor and a helical angle of 45 degrees.
With all the index plates I've made I didn't have one that would give me 17 and 13 spacing so I had to make a new one. Along with this was the need for 2 more helical templates. The thing with the helical templates is that they are pretty much throwaways unless you plan on making the same gears in the future. Each template is made for a specific P.D. and helical angle.

[Admiral_dk]

Nice gears and will be interesting to see if your plans for how well the governor will work after this mod - really hoping that you have success 

Per

[Craig DeShong]

With all the index plates I've made I didn't have one that would give me 17 and 13 spacing so I had to make a new one. Along with this was the need for 2 more helical templates. The thing with the helical templates is that they are pretty much throwaways unless you plan on making the same gears in the future. Each template is made for a specific P.D. and helical angle.

You’ve made many more helical gears than I, George; but I haven’t been able to reuse any of mine either

This engine has the classic styling I just Love.   

[gbritnell]

I have the gears tapped for set screws and fitted and mounted in place. I finished the connecting link that goes from the piston rod crosshead to the crank arm. This was cut from a solid block. I gave myself the coordinates and stepped off the shape then cut it free with a slitting saw. The support arm from the column was made without the support bushing on the the end. I thought it might be too hard to hold all the dimensions exactly so once the arm was mounted to the column and the piston rod assembled I made the bushing and soldered it in place.

[tvoght]

It is really an attractive engine, George. I have been watching.  --Tim

[crueby]

Beauty!   

[fumopuc]

Hi George, very nice.
And as always sure very small.

[Don1966]

Just beautiful work George you’ve out done my Benson. By increasing the speed of the governor will depend on which weight balls you use. I used brass balls on mine and the ratio was ok at max speed they sling out to full extension. Good luck my friend. Are we going to polish it…?.



 
Don

[gbritnell]

Thanks everyone. Don, your engine is beautiful! I don't think I'm going to buff it because there are just too many tiny pockets to try and get into. If it's half buffed it will look worse than just leaving cleaned up.
gbritnell

[gbritnell]

All of the governor pieces made. The links were cut square on the mill then very carefully the connecting shafts were turned, .050 diameter. All of the rectangular pads and the ends of the upper and lower brackets needed radii put on them. No other way than to carefully file and polish. The balls were stepped off in the lathe with a radius nosed cutter then filed and polished. The link bolts are all M1.2 x .25. I have to make nuts for all of them. In the last picture I held the governor open with a scale and you can see how small the parts are.

[crueby]

More wows. Have to order another box of Wows soon!

[Chipmaster]

Exceptional craftsmanship   
Andy

[RReid]

Let me just add my compliments. Lovely guv'nor!