Building the Frisco 1522

[LocoJerome]

The pilot truck axles are finished. I originally toyed with turning them and then hardening them and grinding them but in the end opted for a little easier path of buying case hardened 5/8" shafts already made to length (9 inches). I then turned a sleeve for the middle of the axle that contains the thrust bearings. This was turned out of 316 stainless that I had laying around. It was a little stringy but finished pretty nicely. The hub was initally drilled and reamed to 5/8" for a slide fit on the axle. The hub was then glued to the shaft with loctite. The shaft was then turned between centers for the remaining work on the hub.  A grease path was bored into the ends of the shaft that intersecting a cross drilled hole. The cross drilled hole was drilled with a carbide bit that was able to cut through the RH60 shafts. The hardened surface produced super sharp micro-needles that kept you from wiping them away with your finger... at least the second time. The grease tunnels were positioned under the needle bearings and the ends in the shafts were tapped to accept a set screw.

[LocoJerome]

Here are a couple photos of the final axle assemblies. The thrust bearing ride between hardened washers and the needle roller bearings are lightly pressed into the journals. The needle bearings are sealed on the outbound end. The idea is that grease injected into the ends of the axle will come up under the needle bearings, flow inward toward the thrust bearings and then upwards through the thrust bearings and finally exit the narrow gap that will exists between the shaft's hub and inner side of the journal.

[LocoJerome]

Two leaf spring stacks are positioned between the equalizers in the pilot truck. The spring stacks were made using 0.52" spring stock from McMaster Carr. A full set of prototypical looking spring stacks turn out to be too stiff so I plan to replace every other leaf spring with a plastic strip to keep the looks and reduce the spring coeffecient. But I'm not going to worry about that until all the wheels and spring rigging is in place.

I cut the spring stock with an inexpensive bench plate shear from Grizzly. It worked quite well. However, drilling the material was a royal pain and I'll look to see if I can come up with a way to punch them when I have to do all the driver and trailing truck springs.

[LocoJerome]

Since I'm catching up on my posts I'll share some non-pilot truck work. I mentioned in the past that the drivers on the 1522 are slightly different than what I was able to locate. Real Trains has some nice looking 21 spoke wheels that are pretty close but the counterweights are crescent shaped with a curved inner edge. The counterweights on the 1522 have straight edges on the hub side and instead of changing the area of the counter weight to vary the weight they instead changed the thickness. The main driver is a Scullin Disc and that I'll have to have custom make.

I purchased 6 drivers from Real Train with medium counter-weights and I planned to see if I could reshape the counterweight. I was concerned this would not work out too well but I have been pleasantly surprised in my progress. I first milled flat the backs of all the drivers so I could easily clamp them to the mill table. I then milled smooth the counterweights of 2 drivers flat to receive a 5/16" plate to build out the counterweight thickness. I plan to just tap the 5/16" plate and bolt the plate on the driver from the back side. I'll add some J-B weld between the drive and plate to fill in any gaps.

To shape the counter weight I used a ball end mill and 7 degree taper end mill to remove most of the counterweight material that needed to be removed. To get the final shape I used a couple different sized carbide burrs in a die grinder. The burrs actually cut better than I anticipated but it is still slow going. I have only finished three wheels at this point but it looks like it is going to work nicely. Here are some photos with a before and after shot so you can see what I'm trying to accomplish.

[DJSteamer3017]

Any updates on your 4-8-2?

[765nkp]

I got to see the pilot truck today out at our track. Jerome is doing a great job, the pilot truck looks awesome.
Can't wait to see the rest of the engine.

Tim

[LocoJerome]

Some photos of the complete pilot truck minus paint. It is amazing how much time one can see and roll it back and forth on two feet of track. Spent a few weeks working on some non-locomotive shop projects and finally hooked up the y axis of the DRO on the mill. It will come in handy soon. Work has begun on the frames.

[Greg_Lewis]

Well you're done with the lead truck but if you need to drill spring stock in the future, I've had success using a carbide spade drill, clamping the stock in a home-made fixture that includes a bar over the spring in which I drilled a hole to guide the drill. Still slow going but I got through all the springs for a 10-wheeler including mains, pilot truck and tender trucks and used only the one drill. I did sharpen it once.

[LocoJerome]

Thanks for the suggestion Greg!

Did you drill each leaf separately? It looks like carbide spade bits are not designed for deep holes so I assume you didn't stack the leaf set and drill them in one pass.

[Greg_Lewis]

Thanks for the suggestion Greg!

Did you drill each leaf separately? It looks like carbide spade bits are not designed for deep holes so I assume you didn't stack the leaf set and drill them in one pass.

Yes, one leaf at a time. It was a long process but it worked fine. No screw-ups (which is very unusual for me!). Here's a shot of the solid carbide bit (and you can see the chipped corner). The fixture is long gone but it was merely two pieces of flat stock screwed together to make a sandwich. One piece was milled with a slot just the right size to hold the flat stock between like it was a strip of bacon in the sandwich. Then a hole was drilled through both pieces to guide the drill. A five-minute project. (The fixture, that is. Drilling the spring leaves took much longer!)

And, of course, you know that carbide wants a very rigid setup; the drill quill can't have any slop in it and the chuck needs to run within a couple of thou true.

[Dick_Morris]

I had better luck putting holes in .042 stock with a carbide spade drill than a punch. I drilled in the mill and didn't use a guide for the drill.

[DanSmo]

Beautiful work Jerome! I'm loving watching your updates, be sure keep them coming.

I'll second Greg with the carbide spade bits. I just finished up all my loco springs, if your interested look at the most recent post in the build log about my UP 4012.

I will add that rather than a spade bit and drilling one leaf at a time I chose to make a jig for each type of spring pack and stack drill using a straight flute carbide drill. That way I was able to get through 5 or 6 leaves before removing the drilled leaves and continuing to drill. The straight flutes do not clear the chips well but they do not trap them in the hole like the spade bits.