Machine Shop / Locomotive Drive Work

[R.K. Maroon]

Bob -- can a nose from a CLW wrapper PA be fitted to the roof and sides of a cast PA? It's a bit of a heresy, given that the wrapper nose is of questionably accuracy, but I have a modified nose that you sent to me some time back. If the choice is that or nothing, it might be worth considering.

In other news: I had a mishap while milling the roof of one of the PAs. The bit (an 3/8" end mill) started to pull out of the collet chuck (and down into the roof) while I was taking a cut on the dynamic brake unit:



I had the collet tight so my first thought was that the vertical lead screw was turning on its own to let the head drop. I gave the collet another tug on the wrench, held the lead screw handle to keep it from turning, and tried again. The bit started coming out again so I changed to a smaller end mill, which required a different collet, and things went fine from there. The first end mill is not pristine, which is why I use it for roughing out material, and maybe it's grabbing as a result. That bit is now retired, but I am interested in hearing what thoughts others may have on this event. The repair is easy in this case, but this could have been a disaster in other circumstances.

Jim

[bob turner]

My chuck has a set screw which must hit the flat spot on the bit. Otherwise they will push or pull - especially the ball ends.

Are you using cutting fluid?

Repair is of course easy - build it back up with brass, solder, and flat head screws. I always think of the cobbler fixing heels.

Let's wait for a good nose. Maybe Lou has the patterns? There are still a few foundries that can do this stuff for less than an arm/leg. Plus - somebody surely has fragments? I don't do Facebook, but an ad in MRR always used to get results.

[bob turner]

I went to the Kalmbach web site to see what classifieds cost now. Almost impossible to navigate on an iPad. I haven't even seen an MRR in decades - last I heard, minimum classified was $35. But they reach far and wide, even to O Scalers.

So for now - $50 for the first pair of nose castings offered. Saving $35 is the goal there. I will mention it on OGR. More folks go there . . .

Building a nose from scratch is not impossible - and the extremely accurate MTH nose can now be had for $25 on eBay, then "lost-waxted" for a hundred bucks. But I bet we can smoke out some old parts.

[R.K. Maroon]

Bob, I'll post a query on the O Scale Yard Sale site. You never know what's lurking where.

Here is the next step in removing the dynamic brake unit. The roof is curved of course, and getting a clean cut to match that profile was neither practical nor required. I tried tilting the roof in incremental amounts while taking a flat pass, but found that simply stair-stepping it got it much closer with a lot less work:



To know how deep to cut I would run the tool out over the existing roof area to the left (which has the profile I need to match) and lower the tool until it just touches the casting. I leveled the roof front to back to make sure that the depth I started with was the same depth I ended with.

I will work down the residual shown here by hand, but I need to patch the over-cut area first (where the tool pulled out, as described above).

Jim

[R.K. Maroon]

Yesterday, for the first time in I don't know when, I was able to spend an entire day (and a good bit of the evening) on one model railroading project, which was the cast CLW PA. The main goal of the day was to repair the gouge in the roof (see above). Step one was to machine the gouge into a uniform pocket and cut a plug to fit:





I considered working the top of the plug down to closer match the roof line before soldering it in, but I have to mill it anyway so why bother. Step two was to get it soldered in. Not very pretty but no reason for it to be:



One of the challenges was to get the plug soldered in without unsoldering the reinforcing bar that I added under the roof (again, see posting above). I taped off the underside with gaffers tape and then stuffed a wet hand towel up against it. I failed to get a "before" photo but I did get an "after". The green gaffers tape has been removed and is balled up in the top of the photo below. I used my MAPP-Oxygen torch to heat the pocket, thinking the concentration of heat would be best to heat locally without overheating the whole area. It worked like a charm. The plug is securely soldered to the roof on the solder on the underside piece melted a bit and spread to the underside of the roof just under the pocket, but did not run out and the underside reinforcement is still firmly in place.



Next step: Mill the plug down and match the existing milled profile around the plug:





At this point I have recovered from the gouged-roof event. Next step is to work the roof down. More on that to come.

Jim

[R.K. Maroon]

The next step after milling off the dynamic brake unit was to sand off the residual "stair step" profile. I started by draw filing but quickly found that a small wood block wrapped in emery paper was the way to go. Here is the first-pass result:



I wasn't too surprised that I had over-milled in a few places, but I was more interested in the overall profile. It's very hard to tell just by sighting it, as shown in the photo below. A coat of primer should make it easier to see, but as best I can tell this looks good enough.



Many modelers simply will not use epoxy in circumstances like this, which means filling with solder everywhere. I toyed with the idea but in the interest of time went straight to epoxy. I have an industrial grade epoxy by 3M at the shop but I was at home to do this and used J.B. Weld. I super-cleaned the metal to remove all the residual cutting oil, so hopefully the bonds will hold over time.



Back to sanding -- but a little more carefully now:



I have since worked it down to where I can't feel any bumps or edges with my finger tips. Next step with this will be a prime coat as a check, but I have some other milling to do first, including removal of the number board that can be seen on the roof at the front of the nose. The Santa Fe and one of the GM&O PAs used this number board (and perhaps others), but the T&NO did not. Note also that I have added a line of filler between the nose and the roof. There was a mismatch here that will take a little work to feather out.

More later
Jim

[bob turner]

I use filler in such places. When I was a kid, auto body work was lead, period. I have pretty much graduated to good quality Bondo. Auto lacquer-based glazing putty is the last step.

One of my bronze GG1s had an incorrect contour on those areas where the engineer looks out. Bondo - in for a quarter century, no problemo.

[R.K. Maroon]

I don't exactly recall how I got distracted from my project to modify a cast CLW PA to bring it into the correct configuration for the T&NO, but my last post here was in January, when I machined the dynamic brake unit off the roof (See photos above). The only other thing I managed to get done before today was to take off the side marker lights (The T&NO version had the 45-degree angle markers). For this I used files and then a coarse Craytex wheel:



It's going to take a coat of primer to know how well I have matched the contour (not that well, I expect), but there is no reason to do that until all the machining off of bits is complete. Toward that end I mounted the shell back on the mill today and went after the other offending details on the roof, including the steam generator stack and vent and the prime mover exhaust stack, all shown here as arrived:



The steam generator vent and exhaust are located differently on the T&NO version, so off they go. Note how close I have to get to the rivets here:



The primer mover exhaust stack is correctly located but it is much narrower on the T&NO version. Here it is getting close to the correct dimensions:



I have a little bit of shaping yet to do, including machining out the exhaust port. More pics soon, I hope.

Jim

[Jay Criswell]

I'm going to try an experiment here. I just finished a couple of Overland AMTRAK F40s and posted a brief write up on my R-O-W FB page but lots of photos. I know many, if not all, of you don't like or use FB but I find it easier and there's no issue on the number of photos posted. Anyway, I'll post a link. Check it out, or not.

https://www.facebook.com/Right-O-Way-235082016964918/

No, you don't have to join FB to look.

Jay

[up148]

Nice work Jay! The installation on the FP-40's is stellar.

Only issue watching FB for none members is constantly asking the viewer to "sign in or create new account" and then on the videos the entire right side is blocked by comments and again asking you to sign up. But, putting up with this is way better than not having it at all..so thank you.

[Rufus T. Firefly]

I just finished a couple of Overland AMTRAK F40s and posted a brief write up on my R-O-W FB page but lots of photos.

Could have written an article.................

[bob turner]

I like your FB photo essays, but my iPad doesn’t. I will open the big computer and take another look.

Hey Martin - can he publish even though he has already posted? It would be neat to have printed articles on his artistry.

[R.K. Maroon]

I never get tired of looking at machine work, and Jay's of course is second to none.

Jay, I did get a chuckle about your reference to old and obsolete CLW equipment. That's the world I live in!

Jim

[Rufus T. Firefly]

Hey Martin - can he publish even though he has already posted? It would be neat to have printed articles on his artistry.

We can work that out.

[ScaleCraft]

I'm gonna try some roof milling. I just got a set of cast F3's, A and B, no frames or drives....and figured to remove the steam heating roof stuff off the lids (center roof on H0 Varneys lift out!). Just gonna try and see.