Looks like a fantastic time.

Nicely done Bob. Another quality repair!!

Over the years I've tried many different ways to get reliable all wheel electrical pickup with P&D's beautiful cast brass Blomberg trucks. From P&D only half the wheels pick up power from the rails, and that goes through a torturous path involving rotating and sliding parts. How can one add reliable all-wheel pickup wipers?

There's not a lot of room in the trucks, since they are very close models to an equalized and sprung Blomberg B truck. Yes, one of the cross bars at the left end of the truck is still sitting in a jar waiting for installation.

Reminder: Click on a photo to enlarge it in a new window.



Just before the 2023 Denver O Scale Convention I purchased some excellent photo etched wipers from Rod Miller, but didn't have time to do much with them. These wipers are 3mm tall and etched from 0.008" phosphor-bronze. Over the last couple days I've been designing and milling wiper mounting blocks from raw 1/4" Delrin bar stock.

Here's a first "dry fitting" assembly. Two 0-80 screws hold down the wipers, which were right angle bent using an etched metal bending tool. A single 2-56 screw runs up the bottom through the spring plank center oval hole to keep the block in place. All screws are 1/4" long, and the 0-80 screws stop just shy of exiting the Delrin, so no short circuits.



The wipers still need to be formed and cut to length. Just past the edges of the Delrin block I plan to bend them outward to produce the primary spring tension. They will wipe on the back of the wheels approximately at axle height. Because of the contact position, friction will want to raise one end of the wiper and lower the other end. To counter this, the wiper sits in a 3mm deep x 0.1" wide rabbet that supports the wiper edge and prevents it from twisting or rocking up and down. A little shelf below the wiper's edge keeps it from shorting to the spring plank. If my calculations are correct, there should be about 0.040" of clearance above to the next potential short circuit surface.

Bends were made using a new/never used etched metal bending tool.

Because I make lots of mistakes while manual machining, I started with 40 Delrin blanks and spoiled 4 before I got into the flow over several days. 36 survived the process. To be honest, after hand tapping two 0-80 holes 1/4" deep I was dreading the future of my wrist. Then it dawned on me to grab a cordless drill and power tap. All 72 0-80 holes were tapped in a jiffy! Normally I wouldn't try to power tap in metal, especially gummy aluminum, even with a 2-flute "gun" tap that shoots chips forward and out the other side of the hole. Delrin is ultra-machinable, and not once did the 3-flute tap come close to jamming.

Thanks to Rod Miller for sharing the Mouser part number for the tiny crimp lugs. I think I'll solder some very flexible Adafruit black silicone insulated 26 AWG wire into the lugs.

Now it is time to start painting some trucks and frames.

Next up, the depot.  I'm thinking a brick structure with brick pilasters and a metal seamed roof.  A second story turret houses a railroad management type office.  I think the turret will help visually balance the 20 scale foot height difference between the tracks at this point of Mt Union, but not overpower the scene like a full 2 story building. An operators bay window faces the Antioc & Dover tracks on the aisle side and will support a train order board that will be used to issue instructions for A&D staging adding a little variety to layout operations. Deep over-hanging roof eves and an extended stand alone roof will shelter a cement platform.  A team/LCL track will have a boxcar door height dock on the back side.  This dock will help visually transition the middle of the scene from A&D "ground level" at front to A&O "track level" at the back and break up the long retaining wall along the upper tracks. Of course, construction will be primarily styrene and all scratch built. 

Here is the front wall so far...

Beautiful craftsmanship as always Rick!!  It is even more impressive in person!!