Etching ideas - (biased towards diesel handrails)

[Chris333]

Damn, I just measured and checked against the drawing. There is hardly any undercut at all.  I thought I read that 1/3 rule at another etchers site long ago. Or perhaps PPD min line width of .18mm is enough thickness to make up for any undercut.

Oh well, carry on....

[GaryHinshaw]

[I thought I posted this this morning, but I guess I only hit Preview instead of Post.]

Thanks for the info guys, good to know about the 0.2 mm option.  Is James the PPD POC for this kind of stuff?

I figure I'll try a few dimensional variants before committing to anything in large quantities.  I'll probably also keep posting grab shots of ideas for further feedback before submitting anything to PPD.  The feedback is quite helpful.

To that end, I was looking at the side sill/platform assembly on the '70MAC again and I think the attachment that makes the most sense is a flange that folds under the side sill and has two loops that fit over the posts that hold the under-frame detail casting.  I think this would be simple, sturdy, and would provide pinned alignment.  Here's a very rough sketch: (e.g., I have not attempted to put the pin tabs in the proper location yet.)



So the whole bottom flange would fold into the page, under the side sill, and the extensions with the pin holes would sandwich between the walkway and the under-frame detail.  (One might want to file a bit of clearance for those extensions, so no gap opens up between the castings.)  The actual side sill would not be covered over in this design.  Comments?

-gfh

[Chris333]

James is who answered all of my e-mails.

[Sokramiketes]

Usually James, when he's out, John fills in.  It's not a large shop, so just send to the PPD email and they'll take care of you.  They're usully fine with running test shots too.  If they're concerned about artwork or their capabilities they'll run a sample and send photos.  Or at your request send you a part, though that takes more time. 

[James Costello]

To that end, I was looking at the side sill/platform assembly on the '70MAC again and I think the attachment that makes the most sense is a flange that folds under the side sill and has two loops that fit over the posts that hold the under-frame detail casting.  I think this would be simple, sturdy, and would provide pinned alignment.  Here's a very rough sketch: (e.g., I have not attempted to put the pin tabs in the proper location yet.)

So the whole bottom flange would fold into the page, under the side sill, and the extensions with the pin holes would sandwich between the walkway and the under-frame detail.  (One might want to file a bit of clearance for those extensions, so no gap opens up between the castings.)  The actual side sill would not be covered over in this design.  Comments?
-gfh

I like it. I'll be willing to give it go anyway.

[ednadolski]

A few thoughts:

- I looked at the handrails that came on Bob’s N-scale Walong signal bridge kit, as these are the closest thing I have to what we are talking about.  Measuring with the calipers, the thickness of the brass is 0.010”, and the width of the handrails is approx. 0.011” – 0.012”.   I'm concerned that this may look a bit wide/flat in photos, esp on the loco ends.  I’ll see if I can get a pic to post in the next day or so.

- I think that some kind of sidesill is essential.  By themselves (no sidesill), the signal bridge handrails are very delicate and easy to bend when removing from the fret.  No doubt that some of this is due to them being brass, so I think stainless steel will be very important too.   (FWIW, that’s one of the really nice things about the phosphor bronze wire that I use for scratchbuilt handrails – it’s very durable for its size).  Gary, can you comment on the strength of the Athabasca part in your photo?

- I’m not completely clear on where you intend the bend lines to be for the folding portion of the side sill, but I am a little concerned that making all those bends uniformly enough on an elongated piece like this could turn out to be tricky.  As a general rule, it’s probably best to really try to keep bending/forming to an absolute minimum.  That said, some level of bending/forming will be unavoidable, esp. for some of the vertical handrail portions, and at some of the attachment points.  For those areas, a half-etch bend line would probably help a lot.  BTW, at these sizes the bend radius will also need to be considered.

- On many diesels the base of the handrails actually overlaps the sidesill, so I’m not sure how to achieve that with a sidesill that folds underneath in some manner.   Another possible concern is how to do folds when the walkway has a step or two somewhere along its length – if the folds aren’t done precisely enough, the parts won’t fit well.   So it still might be worth considering sidesills that do not fold, and just overlay the existing sidesills.  In that case, most of the sidesills would be a half-etch, so the slight additional thickness would not be too much of a concern.  I wouldn’t worry too much about paint matching, since a model detailed at this level typically requires paint matching anyway for all the other parts that get added (e.g., sunshades, grabirons, fans, etc), plus they get weathered too.

- It will be important to strategically locate the attachment gates to the rest of the fret, so that the parts can be cut from the fret (a) with a minimum of damage, and (b) without leaving objectionable burrs if the cut is less than perfect.  Basically this means the gates will have to go at the stanchions (or better yet, on the sidesills), since cutting a gate in the middle of a slim handrail span will almost certainly introduce bending and/or leave a noticeable burr.  Filing off burrs on parts this size is something best avoided entirely. Also important, the fret design must leave enough room to get in there with the tip of the photo-etch shear or other tool, in order to make the cuts.

- The end pilot stanchions & handrails will not be able to have a sidesill on models that have anticlimbers.  I don’t see this as too big a concern, since the end handrails are not nearly as long as the side handrails.

- The modeler will still need to do some careful drilling, in order to attach the end pilot stanchions to the model.  To precisely locate the holes for these, it might be a good idea to etch a drilling template at some convenient/usable location on the fret.  It will also be necessary for the modeler to drill where the handrails attach to the step wells.   (Maybe each kit should come with a #80 bit  )

Ed

[Sokramiketes]

Stainless is strong, but remember that it will take some extra effort to get paint to stick well in the long term.  They don't call it stainless for no reason...

I haven't had any run yet, but PPD did say they can etch phosphor bronze and silver, so maybe there are other materials to look at.  The nickel-silver that M&R Models uses for passenger car sides (Alpaca?) is pretty durable as well and holds paint well.

[GaryHinshaw]

I was thinking of trying the phosphor bronze in the same test run as the .010 and .08 SS.

Ed, if you look back at the first shot of the Athabasca kit, the attachment points are at the tops of 3 stanchions, precisely to avoid the bending problem you mention.  I was able to cut those quite easily with a blade, but it was a bit tricky to get the nippers in there cleanly.  In any case, I'd follow the same design.

Once released, the piece is prone to bending until the bottom of the stanchions are secured.  That is what made me think a bottom runner of some kind was necessary.  In my sketch above, I envision the fold line being where the long flange meets the bottom of the stanchions, and that I'd include a half-etch on the back side to accommodate that. I think most Kato models have a flat surface under the side sill, so that no complex bending would be required.  But it might help to mock something up and take some pictures to illustrate what I'm thinking of.  Stand by.

-gfh

P.S. Hopefully stainless can be made to hold paint at least as well as derlin...

[GaryHinshaw]

Ok, if a picture is worth 1000 words, then 5 pictures is TLDR.  First up are some shots of the undersill and skirt detail to illustrate the attachment concept a bit better:





Hopefully you can make out the pins that the skirting attaches to, these are what the tabs with the holes would mount to.  You can also see that the under-frame is chamfered a bit, so the long flange would have a bend that is slightly less than 90 degrees and the pin-hole tabs would bend all the way to 90.  This seem like a really simple, robust approach for the side rails, one the measurements are perfected....

For fun, I also took the Athabasca rail and Goo'd it to the side sill an snapped some shots.  Bear in mind it's the wrong size & style, but hey.







The first shot gives a good indication of why I hate the Kato rails so much: thick stanchions that lean in and/or wobble.  The second shot shows why I love the etched rails so much.  The last shot was the harshest close-up I could get with the light I had, so you can get an idea of how the square rails look in a photo.

-gfh

[Philip H]

Gary,
That is real hotness.  I have a couple of his etched cab kits from years ago - the handrail definitely look worth some coin.

[ednadolski]

In my sketch above, I envision the fold line being where the long flange meets the bottom of the stanchions, and that I'd include a half-etch on the back side to accommodate that.

I think I see what you mean, but I still see a few concerns about a folding flange:

 - With a folding flange it may be necessary to bend all the stanchions at once, in order to prevent unwanted twisting. This could require some kind of bending tool long enough to accommodate the entire part.

 - I don't see a way to avoid having a visible edge of metal about 0.010" thick at the bottom of the sidesill.  It still would have to be painted to match, and carefully aligned in order to avoid a noticeable line.  (Even if fitted & painted perfectly, that adds ~ 1.6 scale inches to the vertical thickness of the sidesills -- not huge by any means, but probably noticeable under a close look.)

 - Unless you want to make the base of the stanchions oversized, there will be gaps between the new stanchions and the sidesills where the old, overly-thick plastic stanchions used to pass through (certain models like IM instead will have the holes that were drilled for the old stanchions).

 - I think bend radius is still a consideration.  I'm not sure, it it preferable to have the etched fold lines on the front or on the back?

 - A folding flange is only usable where the stanchions all line up at the very bottom edge of the sidesill.  On some locos like these (http://www.locophotos.com/pix/91/BNSF%20Railway%20BNSF%20599_Barstow%20CA_Scott%20Barr_2008-07-03_91693.jpg) (http://www.locophotos.com/pix/95/BNSF%20Railway%20BNSF%205600_Whiting%20IN_Mike%20Rapchak_2008-09-07_95720.jpg) the first couple of stanchions behind the cab are mounted much higher up.  Also on some locos, the bottom edge of the sidesill isn't a single line: (http://www.locophotos.com/pix/12/Montana%20Rail%20Link%20MRL%20302_Riverdale%20IL_Mike%20Rapchak_2004-10-17_12945.jpg)  (That's one clever thing about the Alkem design, the way it blends in at the existing panel lines on the model.)

Those last couple of pics are extremely interesting, I think they show that this has a lot of potential.   BTW great job on the grabirons too!  

Ed

[GaryHinshaw]

Hi Ed,

All good points for sure - thanks for taking the time to help me think this through.  A few comments in response:

- With a folding flange it may be necessary to bend all the stanchions at once, in order to prevent unwanted twisting. This could require some kind of bending tool long enough to accommodate the entire part.

Yes - I was imagining a thin scale ruler as a bending tool.  With a half-etch bending line, this should be a fairly easy bend...  We'll have to try it though.

- I don't see a way to avoid having a visible edge of metal about 0.010" thick at the bottom of the sidesill.  It still would have to be painted to match, and carefully aligned in order to avoid a noticeable line.  (Even if fitted & painted perfectly, that adds ~ 1.6 scale inches to the vertical thickness of the sidesills -- not huge by any means, but probably noticeable under a close look.)

Right again.  I was thinking of half-etching the flange to make it thinner, but that may impact rigidity.  The thing I like about the folding flange (in addition to its simplicity) is the it would add lateral strength and force good stanchion alignment.  Since the rails themselves need to be painted, I think painting the flange comes for free, so that shouldn't be too much of an issue.

- Unless you want to make the base of the stanchions oversized, there will be gaps between the new stanchions and the sidesills where the old, overly-thick plastic stanchions used to pass through (certain models like IM instead will have the holes that were drilled for the old stanchions).

 - I think bend radius is still a consideration.  I'm not sure, it it preferable to have the etched fold lines on the front or on the back?

 - A folding flange is only usable where the stanchions all line up at the very bottom edge of the sidesill.  On some locos like these (http://www.locophotos.com/pix/91/BNSF%20Railway%20BNSF%20599_Barstow%20CA_Scott%20Barr_2008-07-03_91693.jpg) (http://www.locophotos.com/pix/95/BNSF%20Railway%20BNSF%205600_Whiting%20IN_Mike%20Rapchak_2008-09-07_95720.jpg) the first couple of stanchions behind the cab are mounted much higher up.  Also on some locos, the bottom edge of the sidesill isn't a single line: (http://www.locophotos.com/pix/12/Montana%20Rail%20Link%20MRL%20302_Riverdale%20IL_Mike%20Rapchak_2004-10-17_12945.jpg)  (That's one clever thing about the Alkem design, the way it blends in at the existing panel lines on the model.)

So far I've only really been looking at the '70MAC case, with an eye towards other Kato models. I'm pretty sure that other approaches will be better for other models.  Suggestions are always welcome.

I'm thinking the half-etch for the fold should be in the back...

Those last couple of pics are extremely interesting, I think they show that this has a lot of potential.   BTW great job on the grabirons too!

I thought you would like those.   

-gfh

[GaryHinshaw]

Reviving yet another old thread....  I have finally had some time to get over the hump with some CAD software so it's time to revisit this topic again.  Here are some screen grabs of the current status of the '70MAC handrails.  The main thing I've accomplished is to design a modestly detailed stanchion that I could easily replicate (and modify) and have now laid out the long side rails.  The shots below show an overview and two close ups (with and without mask fill).  As drawn, the rails are .01" wide (and thick) and I expect they will etch down to a bit thinner than that.  Next up is to get more serious about the bottom sill (as discussed above); lay out the end rails; and figure out how to translate the 3d geometry of the stair rails back to 2d...

Comments on any aspect of the current drawings is welcome.   One specific question: the rivets in the stanchions are drawn as .04" diameter circles of un-etched metal surrounded by half etch.  (They don't show up very well in these screen grabs.)  Will that small a detail survive with any fidelity?  Should I make them bigger, or maybe just leave them off?

I can't wait to try this out on an SD40-2...

Cheers,
Gary

[Denver Road Doug]

Gary,

Not sure how I missed this discussion before, but I would definitely be in for a handrail kit for the SD70MAC that is similar to the SW1200RS kit.  I have that kit, too...bought to upgrade a DRGW SW1200.  But as someone mentioned in one of the other threads, they are very specific to a locomotive and because the setup of the handrails on the prototype I was trying to build, I couldn't use the RS mod.  I think I have 6 or 7 70MAC's and would immediately buy kits for all of them if you can make it happen.

Would also be interested in C44-9W, SD40-2, and GP40 among others.

Doug

[TiVoPrince]

SD70MAC 
is not my game, but SD40, SD45, SD40-2, SD40T-2, SD45T-2, GP40-2, and SD60 are of particular interest.  Nice to see this thread resurrected...