Keyed Washer/spacer

That is really cool. I need a washer like that myself only much bigger. It is to lock the 4wd in my Tracker. Actually I need two of them & I've been trying to figure out a good way to make them.
 
Could you make the washer thicker than the specks that you stated? If so you could do something like Atlas did on the end of there leadscrew. It is a thick washer with a hole drilled in the side and a pin pressed in that rides in the key way.
 
Hi Rob, if only, I have a minimal amount of space for this.
Added a higher voltage and temperature rated cap yesterday, still started smoking after 10 mins.
Decided to dismantle the welder and take some measurements.
Voltage 78V dropping to 57V when burning, phew, a bit high.
The resistance in the coil was only 2.3 ohms instead of the desired 25 ohms.
Hmmm some serious re-thinkng to do.
I may plug a house lamp into the welder output to try and drop the voltage and see what happens.
I'm about halfway through the stainless now. The worlds most expensive washer:bang head:
 
savarin said:
The worlds most expensive washer:bang head:
Click to expand...
I run into this all the time. Most of the things I make us because I need it now & don't want to wait or don't want to go to town. I needed 3 lugged connectors made of aluminum. They cost about $10 to buy so I thought I can save a few bucks & just make them. Well I saved $30 but a few hours later I wished I'd just bought them.
 
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I am by no means an EDM expert, however try using a higher flow of dielectric fluid in order to flush the debris from the cutting area, if particles of conducting metals are floating about in the fluid the resistance drops considerably. I am quite sure that you are well aware of this having gotten as far along as you have.
 
savarin said:
The worlds most expensive washer
Click to expand...

I don't think so.......
http://www.amazon.com/gp/product/B0...&tag=pressurewashr-20&linkId=MEL7IZSPASBG36G5
http://www.chacha.com/question/what-is-the-most-expensive-washer-and-dryer
http://www.ebay.com/itm/NASA-SPACE-SHUTTLE-CHALLENGER-FLOWN-IN-SPACE-WASHER-/221255497490?rmvSB=true

...but seriously......I am collecting ideas and parts to attempt a build of an EDM machine. There certainly are many different designs once you start searching around.
I have divided the ones I've found into 3 different groups:
1) vibrator with discharge circuit in series with the electrode control; manual advance
2) vibrator with separate discharge and control circuits; manual advance
3) stepper motor (much more complex control); automatic advance

...and that does not even consider different discharge voltage amplitudes, polarity, constant vs. pulse voltage, dielectric fluids, pumps, etc.

I suspect that:
For 1) the power supply, coil, total head mass and discharge capacitor need to be tightly tuned to work well together.
For 2) since the discharge circuit is separate from the head control circuit, the parts could be chosen more independently.
For 3) it is a significantly more complex build, however, using a stepper motor driver from a third-party supplier, it may be much simpler than previously published builds. Also, as long as the total head mass is within the capacity of the stepper motor/lead screw it should be more independent of chosen parts.

I am not sure which type to try first. If I had the time I'd build them all and test each. However I suspect 2) to be the best "bang for the buck" in terms of part tweaking and time/money invested.

I have a few other projects on the go too, but hope to try some of this over the next 2 weeks.

-brino
 
stuck another cap same value in series and that trebled the working time before it got got to the touch.
The coil now gets very hot.
Next upgrade is to wind a better coil with thinner wire and get it to as close to 12 ohms / 25mh as I can.
Then if it will work without the coil or caps overheating I will build a posh new head.
now 3/4 of the way through, the bottom of the burn has little peaks corresponding to the porosity holes in the brass electrode.
 
brino said:
I don't think so.......
http://www.amazon.com/gp/product/B0...&tag=pressurewashr-20&linkId=MEL7IZSPASBG36G5
http://www.chacha.com/question/what-is-the-most-expensive-washer-and-dryer
http://www.ebay.com/itm/NASA-SPACE-SHUTTLE-CHALLENGER-FLOWN-IN-SPACE-WASHER-/221255497490?rmvSB=true

...but seriously......I am collecting ideas and parts to attempt a build of an EDM machine. There certainly are many different designs once you start searching around.
I have divided the ones I've found into 3 different groups:
1) vibrator with discharge circuit in series with the electrode control; manual advance
2) vibrator with separate discharge and control circuits; manual advance
3) stepper motor (much more complex control); automatic advance

...and that does not even consider different discharge voltage amplitudes, polarity, constant vs. pulse voltage, dielectric fluids, pumps, etc.

I suspect that:
For 1) the power supply, coil, total head mass and discharge capacitor need to be tightly tuned to work well together.
For 2) since the discharge circuit is separate from the head control circuit, the parts could be chosen more independently.
For 3) it is a significantly more complex build, however, using a stepper motor driver from a third-party supplier, it may be much simpler than previously published builds. Also, as long as the total head mass is within the capacity of the stepper motor/lead screw it should be more independent of chosen parts.

I am not sure which type to try first. If I had the time I'd build them all and test each. However I suspect 2) to be the best "bang for the buck" in terms of part tweaking and time/money invested.

I have a few other projects on the go too, but hope to try some of this over the next 2 weeks.

-brino
Click to expand...
Brino,

I hope that you will post your progress along this journey. I have been considering using the Tormach CNC to feed the electrode. It is capable of programmed movement in the micron/sec range. It can also be programmed to do a peck operation which could be useful.

Bob
 
From my limited experience I have found that having the dielectric heavily flushing the burn keeps the arc more stable and burns faster (what two weeks to burn the hole so far?)
The pecking the solenoid does definitely helps in this.
I've also moved the armature further into the coil at the start and made an adjuster for the coil top to allow it a small amount of movement so the armature doesnt bind, this has made it actually hammer the workpiece burning much faster.
I would like to build a pulse unit but its out of my skill range I believe but I am still impressed with the simplicity of this design and the fact it works at all.
I stripped the coil from a small 240V fan motor yesterday and the laminated armature is a square section that smoothly slides in and out of the coil.
I may use this as the new coil and and armature once I've taken some windings off as its reading a very high resistance.
Also found a mate with a meter for measuring millihenrys so hopefully I can get the inductance correct.
Its a good job I'm not using this to make money. Hopefully once its all running smoothly I can let it go unattended for short periods or time.
 
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