The Home Machinist!

I have to say, it sure is different from my HO scale days, working on a turnout that is nearly 12' long.

I made some good progress tonight. I got the last of the welding done on the riding car trucks, painted the bolsters, installed the bearings, and then mounted them to the riding car frame. I just need to get some allen head bolts and flat washers, and I'll be putting the springs in these trucks.

Here's an end view. No wheels yet obviously.

Hey, so on a different subject, the Honda GX390 is mounted to it's old pressure washer frame still. There is rubber motor mounts that allow the engine to move/shake a little, should I use these or solid mount the motor? I have to make the plate for the rear of the locomotive frame soon where the engine will mount, and it looks like the pattern will be different if I use the rubber mounts vs. solid.

Ryan, what are you attaching to the output shaft? Hydraulic or chain/sprocket would probably do better with a rigid mount.

Glenn

I'll be direct mounting a hydraulic pump and adapter housing to the output shaft side of the engine cases. I'm planning on using flexible hydraulic lines between the hydraulic pump and motors(the trucks will obviously need to pivot around turns) so it wouldn't hurt to have the motor move around a little. It's a big single cylinder and she's gonna shake so I'm leaning towards using the rubber mounts if it makes sense to do so.

Critique: I dont like the open end of the axles. It allows twice the dirt and dust of running to get into the works, seals or not. i understand the bearing pads for use just not the open end. In my taste, some sort of tin cap would complete the look and eliminate half the contamination. Regular greasing will flush most of the junk out of the bearings when in use, so it is a small deal anyway, more of an eye shine thing.

I hope you get some wheels going soon. Flat plate and welded rings of pipe can get you rolling, but iron or steel is a better more permanent deal. What diameter wheel are you looking at about 7 inch? bar stock unless scrapped is going to get pricey for my liking, but then large scale is.

The engine will live ok with it jumping around on rubber, but your pump mount will want to work loose all the time. The usual lovejoy coupling will work well and give enough life to the setup. Use your head and split the drive hose feeds early and use the smallest size practical for the flow to the motors to maintain flex and not put any side force on the trucks that would influence tracking. That means that the hose should enter parallel to the center line of the car for equal swing in a turn. The motors will be locked together for speed because of the contact with the rail. Put them in parallel not series or you will create a pressure drop. I think you know most of this, so pardon me if I am preaching to the choir. It is easy to make changes now rather than throw parts at a bad design. I cant wait for the initial trial. Dont forget that a metal tank will draw the heat from the fluid and act as a radiator when you run long. Help it if you can.

Good luck, get er done!

rkcarguy wrote: ↑Wed Oct 17, 2018 12:35 pm I have to say, it sure is different from my HO scale days, working on a turnout that is nearly 12' long.

I'll bet! But it's easier on the old eyes...

I'm planning on cutting the axles flush and making some kind of cap that mimics the roller bearing cap with the three bolts on the end, but it's not high up on the priority list at the moment. As far as the seals go I'm not worried, the bearings aren't "open" on either side, and at ~17" from side to side they will in under my 20" wide frames so I'm not worried about rain or anything. Aside from that, I modified my side plates so the wheel sets and bearings drop out the bottom and can be easily changed.
Yes I've planned to use a Lovejoy coupler or equal. As long as the adapter fits tightly I haven't had any issues with things working loose as long as I used Loctite.

Regarding the hydraulics, I've discussed this at great length earlier in this thread and it was determined that I needed to plumb them in series or it would allow one truck to slip and then all the power would be diverted to that truck much like an open differential spins the free tire uselessly in the mud.

As far as cooling, I'm planning on partitioning part of the inside of the locomotive. The motor will suck in air from the back and blow it into a exhaust corridor which I'll line with rock wool and perforated metal in the left rear of the body. Then the flow will exit the locomotive around the stack and behind the "fuel tank" and keep air flowing over all the exhaust parts. The real fuel tank and hydraulic tank will be inside the middle of the body and gain cooling from the front and top grilles. I even have a small 10" A/C condenser fan I could mount under the top grille if needed.

I am doing the hydraulics system pretty much dead last, so there is time to figure this out. I have the specs for the bolt patterns, case sizes, everything I need for the motors and pump, so as long as those don't change it will be a bolt in scenario once everything else is done.
I do have 32 wheels to make ugh, and that's just for starters. The #'s are fairly simple in 1/6th scale. 6" for 36" wheels, 6.7" for 40" for the locomotive, and it looks like the bulkhead flats should have 33" or maybe even 28" wheels and would be 5-1/2" or 4-5/8". This is tire diameter, so plus 5/8" to leave me 1/4" flanges and some material for a clean up cut.
I have 8 burnouts for 6" wheels that will be for the coal hopper "riding car", I'll be doing the rest this way as well with plasma/laser cut 1" plate circles I'll turn on the lathe. I'm actually thinking I may drill and ream the axle holes on the mill, along with drilling two bolt holes in each wheel. Then these would slide onto a hub I could put in the lathe at my convenience and turn the wheel profiles.

Machining wheels is a boring (pun intended) job that I tire of. I usually do four at a time so I do one operation on each before I flip or move and have to reset all the dials on the machine. I have a bolt cut down to a a mandrel that fits a bored out wheel for the second operation where I can cut the flange and tread with a form tool in a couple of swift passes. Learning to trust your dials and keeping the tools sharp is the challenge here.

I disagree on the series thought of flow, but its your build, I am sure you will work it out in some manner. Creating models that do work is a lot more than fit and finish. Design, execution and pride of doing is what drives the rituals. Most impressive so far. Again, good luck.

In 7-1/2" gage it would sure be much easier, I could machine wheels for 1/8th scale in a couple passes on our big lathe and it would go much quicker. I have built, worked on, and done R&D on a lot of things in my various lines of work over the years, and feel like I have a pretty good handle on what I'm doing. Hydraulics are a bit new to me, and will have a learning curve for sure. I'm merely leaving myself some extra space, and through the chain drive reduction from the hyd.motors to the axles, leaving myself room for adjustment of the final drive ratio in case I miss something or want to fine tune my speed/torque. The hydraulic motor mounts will be fairly easy to remove and replace, should I end up changing to a different motor size/model. Ideally, I think a "pancake" type pump (2 in 1) would separately serve the two motors through a multi-circuit actuator in the best way possible, but would be prohibitively expensive and complicated. I've watched the videos of "Bigdumbdinosour"s F-7 run and been through his build thread several times, his motors are purported to be plumbed in series, the only difference being he's running a torque converter of some sorts and I won't be.
Magnetic dial indicators are extremely important on the lathe I wouldn't attempt making wheels without them. I plan to use an indexable carbide tool, and rough cut the wheel profiles first. Then, I will use a new corner of the insert for every few wheels to assure they are really close to the same size.