Pickering governor in 2 inch scale

[gbritnell]

Gentlemen, many years ago I was at an old engine show and found a full sized governor for sale, cheap. Being interested in all things mechanical, and this thing sure was mechanical looking I bought it. What I was going to do with it I had no idea. Last year while cleaning my garage and moving this thing around I thought, that would make a great model so I took it apart, made drawings and commenced to cut metal. Everything is made from solid and along with building it, it was supposed to operate. Well everything operates, the safety mechanism, the balanced valve, etc. but the flat springs that hold the balls in place won't flex enough to let it work properly. I wondered what I could make them out of and after cutting small pieces of flat spring stock and flexing them to see how they would work I was about to give up. I then used my feeler gauges for something and the idea came, cut some strips from feeler stock, but what thickness? I started at about .010 and moved down till I got to .006. The .006 seemed flexible enough when cut to the proper width so I cut some strips with my Dremel grinder and a small cutoff wheel. The balls were made in 2 pieces with a slot in one to locate the spring. The balls are held together with a screw that has a tapered head. When everything was assembled I filed the excess screw down flush and polished the balls. So far so good! The springs are held in place in the upper and lower collars by soldering. I made the collars and cut the locating slots at an angle with a .032 endmill. The springs were inserted into the slots and small wedges were inserted to fill up the excess space. Everything was then soft soldered,(50/50 solder). They came out great except for the fact that now that the springs were held rigidly in the collars they could no longer flex like they did between my fingers. I came to the conclusion that although this setup looks prototypical it won't work, at least not in this scale. I had so much time invested in making parts that I finished it up anyway. I now present to you the fruits of all this labor.
George

[gbritnell]

Here's the final four pictures.
George

[chuck foster]

you do some very nice work george 

chuck 

[Bernd]

That's some nice work on such a small project. To bad you can't get the flex problem solved.

Looks like you might need to make the strips narrower.

Bernd

[ieezitin]

George.
Stunning work as always from you.

Why could you not put either a small ball bushing or oil-lite bush in the top collar as to allow it to slightly slide down as gravity is taking place making the balls expand outward.

I know its not keeping with the original, but It would bug the hell out of me if after all those hours spent making this piece the thing was just eye candy.

All the best.          Anthony.

[gbritnell]

Thanks gents, Anthony, the problem is once the springs were soldered into the top and bottom collars they weren't allowed to pivot at their imaginary end point, almost like the spring need to be rolled into an eye at the top and bottom and then a pin put through it to allow it to swivel. The original governor that I copied is built with the springs rigidly attached to the top and bottom collars, the only difference being that the spring arms are 14 inches long so therefore they could flex in the middle. What I learned from the whole thing is that miniature governors are usually built with pivoting links that go from the center of the balls out to their attachment points and have a preload spring between the collars to keep everything extended. It definitely would have been nice to have it functional but in years of building miniatures I have found that certain physical elements don't scale down well, centrifugal force on a miniature flywheel comes to mind, so live and learn.
George

[dsquire]

George

I'm looking at the the first 7 pictures and I'm thinking that this is pretty good work. Then I see picture 8. Is it possible to make parts that small? Or is George a counterfeiter and starting to make over sized pennies. Either way, excellent work George, this is absolutely amazing. 

Cheers 

Don

[Bernd]

   I think he's making over size pennies.   

[andyf]

I have a distant memory of dismantling an old wind-up portable gramophone contained in a leatherette-covered metal box about 1'6" x 1" x 9". Its clockwork motor had a governor with three rather nicely egg-shaped brass weights mounted on flat springs about 3" long. So it should be possible.....

Andy 

[Dean W]

It's great, George.  A lot of beauty in such a small mechanism.
The brass looks to have satin finish.  Is it some kind of treatment, or some fine wire wheel work?

Very nice, all said.

Dean

[Brass_Machine]

 


 

Eric

[steamman]

Hi I have made a similar scale  governor to yours ,I had the same problem of the springs not flexing orstaying in one position after turning the governor at speed in the lathe, if you look closely at your full size governor you find that the balls have a slight  taper and clearance on the upper half of the ball this is to allow a slight movement of the springs before actual main movement of the valve takes place,it also serves to stop the ghost like appearance of balls when they are spinning.I used a very fine slitting saw to cut the slots in mine ,as you can imagine the slitting saw of only .032 thick does deflect and cause a slightly wider slot at the top of the ball I used a allen grubscrew to secure the balls to the springs making sure that the wider part of slot was uppermost on assembly. With regard to the springs I have tried using Spring Steel from old alarm clocks however it is difficult drill or punch holes without breaking and eventually used shim steel instead clamped at each end by pins and circular wedges held in place by a circular collar on both top and bottom ,the pins allow certain flexation radially to the springs this also helps I used a milling cutter 16 thou wider than the width of the spring but mounted the pins centrally, You say you soft soldered your assembly perhaps the heat has affected the feeler gauge causing local loss of flexibility?Also several people in the minature engine world have used double layer springs ie 2No .003" would give .006 total thickness may be worth a try.Finally I agree some things you just cannot scale  and Physics is one of them I myself have tried over several years to get valve that would work in steam without success,so best of luck and keep trying.Steamman