EDM test with Dave and Roy

We build and test a low budget EDM for burning out broken taps, bolts and making holes in hard metals. Stepper motor control is an Arduino UNO set up for gap current control. This was steel

Test with aluminum. Hex hole burned with EDM. 35 -45 volts electrode positive

Redesign with a linear actuator for ram

Copper chill weld repair

Our storage box for a Sioux seat grinder kit was missing the tab one one side to latch the top down. I didn't notice until I'd already painted the box. My plan was to use a copper chill to mask off what I didn't want wire feed weld to stick on and then the tab could be ground to fit. I used flattened copper tube for the chill.

Manganese Steel Safe repair

I got this safe in the mid 80's and didn't get around to fixing the locks until 2019. It had been in a fire with the door open. We got it looking good and used it for fire proof record storage and that was good enough until now. It was made by the Manganese Steel Safe company in the 1920's by the serial numbers on the time lock movements. The metal is steel with around 14% manganese in it. It is non magnetic and tough to machine. High speed steel won't touch it and modern carbide is a slow process. Originally it was ground to fit. This turned out to be an issue trying to fit modern threaded stem dials on it.

Here it is when I picked it up. Took two of their forklifts to lift it.

It weighs 4,400 lbs by the scale at my work. Front axle 2,710 lbs rear 6,480 lbs

To unload it was hooked to my ash tree and I drove out from under it. My neighbor got a huge kick out that process. Then I dragged it into the garage and stood it up.

Here it is refinished but without the locks working. It was short one dial and the other was fubar. I looked for years for reasonably priced dials that fit on a square shank like the spindles on the locks had. I gave up

The door rotates to open kind of like an artillery breech. The are two bolts that keep the door from rotating when it is locked.

Lock plate with two combination locks covers removed and a three movement time lock. Either combination lock will open it and any time movement. Redundancy on these. Combo locks are indirect drive so drilling the spindles to get it open wouldn't do any good. Spindles are tapered and also made of Manganese steel. Pounding on tapered spindle would only make it tighter. These Yale time lock movements became kind of a standard. New movements are available in mechanical and electronic versions and would fit right in this case.

Back of lock plate pin on lever actuates dog clutch that operates bolt mechanism. Time locks inhibit the combo locks until they time out.

Dog clutch, spindles on inside of door

Combination lock spindles had a external square shank that the original dial fit on. We were missing one dial and the other was fubar. My plan was to adapt available modern dials with a 5/16x 40 threaded stem. To do this we drilled the original spindles partway with a 1/2" carbide spade bit and pressed in a piece of mild steel that could be drilled and tapped.

We got Sargent and Greenleaf dials which fit the original dial rings. Notice the spindle taper.

Checking for runout. The locks have a little adjustment for alignment and they turned out fine.

 These are four wheel locks with 100 million possible combinations based on a 100 division dial. The lever is gravity operated so no spring to give out.

I made a lever out of a crank by bending with heat and welding in an extension.

Locks fixed with new dials. Operation is locks set the dog clutch to operate the bolts by turning the crank then the lever rotates the door to open.

Covers not on the combo locks in this picture. The covers can only be removed and installed by another combination setting.

Powermaster booster pump repair

Replace vanes, rotor and cam ring. This pump would run but made no pressure

pump parts come out the end after ring is removed

         Drilled a hole to get at an end of the wire ring

        wear plates, cam ring, and outlet only fit one way as they are keyed or pinned

       Vanes had worn enough that one got out and no pumping happened.

          going back together

Sometimes the wire snap ring can be reused, We used a snap ring on this one with some machine work

Powermasterbrake boosters

Messing around with powermaster brake boosters try to get them to function

This valve was pitted by rust and caused the pump to cycle periodically

hydoboost spreadsheet

https://docs.google.com/spreadsheets/d/1za2yNDR77iZDuC_mNj9syVgZTOP1HXGSpbT4vrS5xIw/edit?usp=sharing

General Electrodynamics scale rehab

I bought a set of aircraft scales to use for the GMC or what ever else. The set had two 5,000 lb scales and one 2,000 lb. Only one worked. Replaced two of the handle springs with a cut down Ebay spring.

     To get them apart there are snap rings and discs that cover two socket head fasteners on the bottom which hold the top on.

These scales operate like a bathroom scale where levers press on the measuring part. These are hydraulic using a gage and a piston that the levers press on.

The brass screw is where the oil is put in. Two of these had o rings that failed and needed oil. At first I used oil that was too high in viscosity and the gages moved real slow. Drained that and put in thinner oil and it worked ok. Doesn't take much oil.

The black part is a diaphragm which the piston presses on. There was rust stuck on the diaphragm which came off with a vinegar soak and neutralized with baking soda.

                                          Levers and top cleaned up

                  Two broken screws, one came out other not.

They did put steel inserts in the aluminium and that did come out.

               Cleaned, greased and ready to reassemble

      Stacked for testing, match pretty close 500, 750, 1000, 1500 and 2000 lbs

  Testing the 5,000 scales to see if they match