You almost convinced me to build this but I should be doing other things and I don't think the local pool hall would approve.

I'm sure I could get a junk starter cheap enough. That could be a good source of pre-made coils.

 

For those of you that haven't been inside a starter motor, when the solenoid pulls in it pushes (engages) the pinion bendix gear in to mesh with the teeth on the flywheel ring gear. When you release the key, the bendix gear retracts so the starter isn't spinning the whole time the engine is running. That is what makes the screeching noise if you try to start your car and the engine is already running.

 

Just that solenoid, mounted correctly in a cue stick would be good enough for breaking.

Again from experience I have my doubts about that. The fuel shout off and even the starter solenoid "may" give enough. short movement "kick" or force. But to do what Ben has wanted from the start, it would take a solenoid of around 30 inches long to both support the cue and give the 15 inches of movement he wants. both the fuel solenoid and starter one have only around 3/4" movement, with no control over either the strength or actual travel. And adding a permanent magnet to the plunger only makes things work in both directions, adding nothing more or less to the mix.

 

That worried me LOL lets see a core with wire is solenoid what happens if you add 3 more and switch them you have a motor.
here one with 2

Now this is the same thing only are core is moving inline

Im going to post a stick moving if I can find enough stuff to make it. been looking for the right size pipe

 

But to do what Ben has wanted from the start, it would take a solenoid of around 30 inches long to both support the cue and give the 15 inches of movement he wants. both the fuel solenoid and starter one have only around 3/4" movement,

Yes, I'm looking to control at least a 15" stroke. A 3/4" stroke from a powerful solenoid would definitely kick a ball, but not in the way I'm hoping. To clarify the vision: I'd like a "pool shot" from this machine to start with a few back and forth short strokes, like a human preparing to shoot, then recoil and thrust forward to hit with controlled strength.

That worried me LOL

I can't tell what you're referencing here...

Im going to post a stick moving if I can find enough stuff to make it. been looking for the right size pipe

Nice. Blazed trails are easier to follow. Thank you.
I spent today working out the bearing solution, figuring out how I can wrap coils closer to the cores and how to make everything without using metal. It was a lot of designing, not much to post. I think I can make it so that the only metal in the device is the wires, the cores and 4 small pins. I'll have a couple hours in the shop tomorrow. I should be able to build much of it and will post progress.

 

The post I was worried about has changed I guess they changed there mind.

 

The post I was worried about has changed I guess they changed there mind.

Could you be more specific? A short search show no post changes.

 

Yes, I'm looking to control at least a 15" stroke. A 3/4" stroke from a powerful solenoid would definitely kick a ball, but not in the way I'm hoping. To clarify the vision: I'd like a "pool shot" from this machine to start with a few back and forth short strokes, like a human preparing to shoot, then recoil and thrust forward to hit with controlled strength.

Then if that is the expected outcome, a series of solenoid connected together isn't the way to get there. There needs to be a geometry in your 'kicker' that allows variable reluctance to do the work. Once the first ferric part of the moving rod is fully enclosed in the first coil, the second ferric part needs to outside of the next coil. Out side but close enough that that coil can act on it, then the same thing must keep repeating until the full stroke is made. Notice I said "ferric" not "permanent magnet". Other than the cheap/simple large degree movement stepper motor, commonly called a 'can stack motor', no permanent magnet is required in the stepper motor, it's only there to keep one from moving between steps, a 'detent' to hold the last position.

 

If he make's it like I posted the first coil will move the core out half way the second coil will pull it across it half way so on and so on.
and some steppers use magnets for the core I think the TS would have a harder time with magnets seeing he is having a hard time now.
If he makes 4 coils right with the core placed right it will move.
Magnets add to it just means they need to be placed right put one set backward and he has a show stopper.
The picture is the rotor of a small stepper the whole rotor is a magnet
that give the small stepper more force for it's size

 

I got carbon fiber tube and cut steel cores that fit snugly inside. They will be spaced by wooden dowels.
These cores are longer and thinner, with more of them. This should give longer stroke. Total weight is still 2lbs.
This is a zero metal solution (thx Sensacell), other than the cores.

Now to build the bearing solution and then the windings. Out of shop time today though.

 

1) Carbon fiber IS conductive- you may still have eddy currents flowing.

2) What is the tube wall thickness? You want those cores as close as possible to the coils.

 

Carbon fiber IS conductive- you may still have eddy currents flowing.

Damn. Really? Well, I guess I'll have to accept that this is better than having the threaded rod, washers and nuts...

What is the tube wall thickness? You want those cores as close as possible to the coils.

Tube wall thickness is 1mm. The method I've devised to wrap the coils should make an air gap of 0.5mm between coils and tube OD. Therefore, total distance (in theory) will be 1.5mm between coil and core.

 

The roller and coil supports are ready to be glued. I ended up using more metal than I thought. Each roller has 2 bearings and a steel pin.

 

The roller and coil supports are ready to be glued. I ended up using more metal than I thought. Each roller has 2 bearings and a steel pin.
View attachment 154521

Nice! ... did you have the plywood structure laser cut by a local supplier?

 

Nice! ... did you have the plywood structure laser cut by a local supplier?

Thanks! Nope. Mini-Helix 18
www.epiloglaser.com/laser-machines/legend-laser-series.htm

 

Thanks! Nope. Mini-Helix 18
www.epiloglaser.com/laser-machines/legend-laser-series.htm

Whoaaa!!! .... how much did that cost you?

 

Whoaaa!!! .... how much did that cost you?

not my money. $17k

 

I got the four coils wound and epoxy coated. This took far more work and tinkering than I anticipated.

My strategy was to wrap the carbon fiber tube in wax paper, then wind liquid epoxy and wire simultaneously around the wax paper. Next step, after everything dries, is to remove the tube and the paper, leaving a coil diameter very close to the tube diameter. I'm not sure how removing the tube will go and I'm not sure how a structure-less coil will react to heat. Part of me thinks it will just fall apart. We'll see.

 

Bet it wont come off.

Epoxy shrinks as it cures, creating very high pressures.
You need a collapsible mandrel inside, so you can get the core out.
Look at tapered collet designs for inspiration.

 

Bet it wont come off.

Epoxy shrinks as it cures, creating very high pressures.
You need a collapsible mandrel inside, so you can get the core out.
Look at tapered collet designs for inspiration.

Bet it wont come off.

Epoxy shrinks as it cures, creating very high pressures.
You need a collapsible mandrel inside, so you can get the core out.
Look at tapered collet designs for inspiration.

I should have bet you. The carbon fiber tube and the wax paper came out relatively easily.
I'm thinking that because the epoxy was in a ring shape, the contraction increased the ID. Just speculating... but it came out no problem.


There is a problem though... I tried to remove the tube while the epoxy was semi-set on the day I wound the coils. (note that the tube was extremely hard to remove at that time, I only got a fraction of an inch after extreeeeme pulling) One of the coils fractured slightly during this process. I immediately tried to align the fractured coil, epoxied the fracture then let everything set.

Today, after the coils were cleared, I put in the carbon fiber tube to check for friction. I felt something snag at the location of the fracture and as I'm thinking that I shouldn't force it, I forced it and out came the small piece of wire on the paper towel in the image.This means that one of the coils is compromised... meaning that this set of 4 coils is compromised... meaning that I'll have to redo this step. What a heartbreak. Damn.

On the positive side, I figured out a bunch of tricks that will make round 2 faster. I also learned to let everything cure completely before removing the tube. Also, the image shows approximately how the coils fit in the coil/roller holder and everything fits pretty well. If anybody has objections to the wire diameter in these coils, speak now. I'm ordering new wire. Thanks.