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Kadee Conversion - 3d printed pilots for MTH SD90MAC

T thor73OGR Forum Member

Since there was some interest expressed in the Williams GP9 pilot thread here, I figured I would post some details of the design for the pilots I'm doing for my SD90. It's an old one and we've been through a lot together, lol, so it's also one of my favorites.

First, a few overall views of the design:

front1front2rear

The blue and gray parts are models of the existing chassis and body shell. Everything else is part of the new assembly. The pilot is intended to be bonded to the body shell, so that the joint can be made seamless, and so that full length handrails can be permanently attached to it (0.040" mounting holes are provided for this). The various air hoses are separate parts, to facilitate painting and weathering. The cut lever is part of the main part and is fixed. The main air hoses are modeled as though they are suspended below the couplers by a chain or lanyard. I figure a bit of thread or tiny chainlink will do here. The MU cable and junction box for the front is a separate part that can be added if desired.

Here is a view of the assembled unit from the underside:

frontunderside

The coupler mount is a separate part, and is bonded directly to the engine chassis. This does a couple of things. Most importantly, it provides a way to disassemble the engine without having to make any changes to the original parts. It also provides a good load path from the coupler to the chassis - the pilot, plow, and body shell are purely cosmetic and carry no load. The engine can even be run, tested, etc. without the body shell installed, but with the couplers in place.

The pilots are intended to be bonded to the body shell first, and then serve to locate the coupler mounts on the chassis during their bonding, to ensure reliable alignment of everything. No guesswork. You can see the features on the pilot that facilitate this in the pic below.

couplermount

Here is what the body shell looks like fully assembled and removed from the engine:

frontshell2frontshell

And here is how it comes apart for maintenance, once everything is installed:

sd90exploded





As far as applicability to other models, the exact model I have is this one: http://mthtrains.com/20-2370-1. It's a 2002 model, but I imagine the newer models probably use the same molds, etc., at least judging from a few of the pics I've looked at. Once the design is truly finalized, I will post detailed dimensions of the parts, so that folks can verify that it will fit their models. Who knows, it may fit other units as well!

So there it is. Comments, suggestions, ideas for tiny-but-cool details to add, whatever - have at it. 

Eric

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T thor73OGR Forum Member
Mike DeBerg posted:

Eric, Looking great!  I thought I recall you saying that the MU, air lines and cut levers are now separate?   Are you thinking you might add a tie or holder for the extra MU hose (yellow) you are showing?  Are you going to add any rivet detail on the lower sheet for the rear pilot?

Ah, the fun stuff! Who doesn't love rivets? I added them on the GP9 pilot as sort of a proof of concept, to see how they looked when printed. But when I looked at a bunch of pics for the SD90 pilot, I didn't' see any. For example:

http://www.railpictures.net/im.../5452.1239945437.jpg

http://www.railpictures.net/im.../4235.1093403940.jpg

http://www.railpictures.net/im.../3296.1218412585.jpg

So I chose not to add any. I do want to improve the detail on the cut lever mounting, so I may add some bolts or rivets there.

I sort of envisioned the MU cable just lazily draped over the cut lever, rather than secured. But looking at pics again now, all the ones I see are actually tied up in some way, so I may revise that. And I think I will add the retaining bars for the hoses, so the crew can then not use them, as seems to be the standard in those pics, lol.

These pics are also where I got the idea for the spare coupler. But rather than two, I figured my crew had already busted one, so they just had the one spare left.

The detail parts are now separate. My thinking was this would make it easier to detail paint and weather stuff. But maybe that's just my limited painting skills talking...

AGHRMattAGHRMattOGR Forum Member SUPPORTING MEMBERMEMORIAL SUPPORTER

I really like this -- cleaner than cutting down the die cast pilot and merging it to a spacer. I especially like that the coupler mounts to the steel chassis as opposed to the body. Are these going to be available for sale? I have a pair of SD9043's that would really look nice with these in place.

I have an odd mix of MTH (FP45, SD45, SD60, GP9, GP20, GP30, FT, SW1500, H10-44, SD9, SD24, C40-8) and Atlas (B40-8, B40-8W) locomotives I don't run that often if you need to borrow some Guinea pigs for prototyping. My recollection is that the SD60 and SD45 have the same pilot structure; the SD9 and SD24 are virtually the same locomotive).

Last edited by AGHRMatt
T thor73OGR Forum Member
Laidoffsick posted:

When you installed the pilot on your Williams engine, what did you use to "bond" it to the chassis/frame?

I like the fact that the couplers are screwed into the frame, because they have to be to pull a sizeable load, or even used in a consist with other powered engines.

Nothing fancy, just gap-filling CA glue. I did prep the surfaces pretty carefully, though - sanded to remove any high spots and to give the surfaces some roughness, followed by an acetone wipe. Stuff is wicked strong with good surface prep.

AGHRMattAGHRMattOGR Forum Member SUPPORTING MEMBERMEMORIAL SUPPORTER
thor73 posted:
AGHRMatt posted:

I really like this -- cleaner than cutting down the die cast pilot and merging it to a spacer. I especially like that the coupler mounts to the steel chassis as opposed to the body. Are these going to be available for sale? I have a pair of SD9043's that would really look nice with these in place.

I have an odd mix of MTH (FP45, SD45, SD60, GP9, GP20, GP30, FT, SW1500, H10-44, SD9, SD24, C40-8) and Atlas (B40-8, B40-8W) locomotives I don't run that often if you need to borrow some Guinea pigs for prototyping. My recollection is that the SD60 and SD45 have the same pilot structure; the SD9 and SD24 are virtually the same locomotive).

Yep, my plan is to throw them up on a Shapeways shop, after I've checked out the finished product myself. It looks like the cost will be about $45 to $55 per set, for the frosted ultra detail acrylic, which worked well for the GP9 set. I still need to set that up, but once I figure it out, I should be able to post pics, detailed dimensions, and so on right on the shop.

Definitely appreciate the offer of some guinea pigs, but it will be be a little while before I get to that point, lol!

Following the thread, so my order for three pairs will probably go in about five minutes after I open the E-mail notification. Keep us posted. Given EMD's habit of re-using existing components, I suspect the pilots will be a close fit for other modern "M" series engines.

richtrowrichtrowOGR Forum Member

Glad to hear the design has the coupler screws going up into the frame. I would be concerned about the load on the plastic alone.

So what is Shapeways Frosted Ultra Detail Acrylic like?  Is it flexible?  Brittle?   I wonder how it would hold up in an accident or derailment, especially since it's bonded to the frame.  Mounting it with screws would allow you to swap out a replacement if it was damaged, where as the glue-mount might be a real mess to do a second time.

I'm not trying to be critical, just wondering what you think seeing as how you've actually done what I've only thought about.

Oh yeah and here's my order...
MTH GP38s and GP40's
MTH SD70M

suzukovichsuzukovichOGR Forum Member
AGHRMatt posted:

I really like this -- cleaner than cutting down the die cast pilot and merging it to a spacer. I especially like that the coupler mounts to the steel chassis as opposed to the body. Are these going to be available for sale? I have a pair of SD9043's that would really look nice with these in place.

I have an odd mix of MTH (FP45, SD45, SD60, GP9, GP20, GP30, FT, SW1500, H10-44, SD9, SD24, C40-8) and Atlas (B40-8, B40-8W) locomotives I don't run that often if you need to borrow some Guinea pigs for prototyping. My recollection is that the SD60 and SD45 have the same pilot structure; the SD9 and SD24 are virtually the same locomotive).

They maybe in real life but there is a difference between the MTH SD9 and SD24 if you look in my thread on the SD24 and the SD45 it will show you what I had to do for a kadee conversion. https://ogrforum.com/t...73#61965511445937073  . The MTH RK SD9  pilot is the same for the RK Scale SD45.   The Premier SD45 2/3R is the same pilot used in the Premier 2/3R SD24. The RK use a different powered truck .  The RK coupler mount is farther back then the premier which has the 2/3R powered truck assembly and it is also longer then the RK version. The older Premier SD45/SD9 use the same Powered truck assembly as the RK. So it is important to know the difference between the premier line. For the new premiers SD24/45 (2/3R) and the Older Premier SD24, I would recommend using the 743s. Also if your going to bolt the Kadee mount directly to the frame. You will need to use a plastic draft gear box to keep the coupler isolated from the frame when you screw them down. This will prevent the coupler from frying the components in the event of a derailment and the coupler makes contact with the third rail. .  

Last edited by suzukovich
AGHRMattAGHRMattOGR Forum Member SUPPORTING MEMBERMEMORIAL SUPPORTER
suzukovich posted:
AGHRMatt posted:

I really like this -- cleaner than cutting down the die cast pilot and merging it to a spacer. I especially like that the coupler mounts to the steel chassis as opposed to the body. Are these going to be available for sale? I have a pair of SD9043's that would really look nice with these in place.

I have an odd mix of MTH (FP45, SD45, SD60, GP9, GP20, GP30, FT, SW1500, H10-44, SD9, SD24, C40-8) and Atlas (B40-8, B40-8W) locomotives I don't run that often if you need to borrow some Guinea pigs for prototyping. My recollection is that the SD60 and SD45 have the same pilot structure; the SD9 and SD24 are virtually the same locomotive).

They maybe in real life but there is a difference between the MTH SD9 and SD24 if you look in my thread on the SD24 and the SD45 it will show you what I had to do for a kadee conversion. https://ogrforum.com/t...73#61965511445937073  . The MTH RK SD9  pilot is the same for the RK Scale SD45.   The Premier SD45 2/3R is the same pilot used in the Premier 2/3R SD24. The RK use a different powered truck .  The RK coupler mount is farther back then the premier which has the 2/3R powered truck assembly and it is also longer then the RK version. The older Premier SD45/SD9 use the same Powered truck assembly as the RK. So it is important to know the difference between the premier line. For the new premiers SD24/45 (2/3R) and the Older Premier SD24, I would recommend using the 743s. Also if your going to bolt the Kadee mount directly to the frame. You will need to use a plastic draft gear box to keep the coupler isolated from the frame when you screw them down. This will prevent the coupler from frying the components in the event of a derailment and the coupler makes contact with the third rail. .  

Forgot about the updates in the Premier line. Good advice on using plastic coupler boxes with the 3/2 engines. My SD24's are the original Premier and used the same truck blocks as the SD9's.

Rich MontagueRich MontagueOGR Forum Member

Wow! Very nice. I also like your concept for mounting everything. Kudos especially for modeling the actual prototype pilot (unique to the SD 80s and 90s) and not simply fabricating a "full" version of the pilot supplied with the model (a re-used SD 60 pilot).  Consider making the holes for the handrails smaller, maybe 0.20. Some of use finer wire for full handrails, and newer MTH models are closer to that. The modeler can enlarge them if heavier wire is used. I dabble in UP and broke down and bought an SD90/43 from the last run to upgrade, but haven't gotten around to it. This makes it a more appealing project.

RM

suzukovichsuzukovichOGR Forum Member
AGHRMatt posted:
suzukovich posted:
AGHRMatt posted:

I really like this -- cleaner than cutting down the die cast pilot and merging it to a spacer. I especially like that the coupler mounts to the steel chassis as opposed to the body. Are these going to be available for sale? I have a pair of SD9043's that would really look nice with these in place.

I have an odd mix of MTH (FP45, SD45, SD60, GP9, GP20, GP30, FT, SW1500, H10-44, SD9, SD24, C40-8) and Atlas (B40-8, B40-8W) locomotives I don't run that often if you need to borrow some Guinea pigs for prototyping. My recollection is that the SD60 and SD45 have the same pilot structure; the SD9 and SD24 are virtually the same locomotive).

They maybe in real life but there is a difference between the MTH SD9 and SD24 if you look in my thread on the SD24 and the SD45 it will show you what I had to do for a kadee conversion. https://ogrforum.com/t...73#61965511445937073  . The MTH RK SD9  pilot is the same for the RK Scale SD45.   The Premier SD45 2/3R is the same pilot used in the Premier 2/3R SD24. The RK use a different powered truck .  The RK coupler mount is farther back then the premier which has the 2/3R powered truck assembly and it is also longer then the RK version. The older Premier SD45/SD9 use the same Powered truck assembly as the RK. So it is important to know the difference between the premier line. For the new premiers SD24/45 (2/3R) and the Older Premier SD24, I would recommend using the 743s. Also if your going to bolt the Kadee mount directly to the frame. You will need to use a plastic draft gear box to keep the coupler isolated from the frame when you screw them down. This will prevent the coupler from frying the components in the event of a derailment and the coupler makes contact with the third rail. .  

Forgot about the updates in the Premier line. Good advice on using plastic coupler boxes with the 3/2 engines. My SD24's are the original Premier and used the same truck blocks as the SD9's.

Just updated my thread for older Premier SD24. I also covered the SD9/45 which share the same pilots. To be honest. If he can do MTH SD9s/24/45, Alco C628/630, and GP30/9 that would make life easier.  I defintly like the idea of body mounted Kadees.

https://ogrforum.com/t...73#61965511445937073

1-DSCF51311-DSCF5132

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suzukovichsuzukovichOGR Forum Member
CentralFan1976 posted:

Awesome. 

What I really need are the Lionel ALCo RS-11 and FM H16-44 pilots, with steps... 

The Lionel ones just aren't up to task. I can add my own cut levers. 

image

imageimage

Funny with that I took a look at my Weaver RS11. The pilot turns out although less detailed,  did have a correct pilot as in the above pics.

T thor73OGR Forum Member

Thanks for the suggestions, everyone. I had a little time to play with the model this morning, and I've incorporated most of them, along with a few other tweaks. Here's the latest:

front3rear3



I also added some real estate on the coupler mount to allow the use of screws in lieu of adhesive, if desired. The mount will have reference marks on it for suggested locations that avoid some features in the original body shell. There is enough room to allow up to five screws.

couplermount2

I should clarify that the coupler screws do not go all the way through the coupler mount into the chassis. I did not want the position of the coupler to be driven by features on the chassis. Most importantly, with the coupler in the correct position the row of three coupler screws overhangs the edge of the chassis.

couplerscrews

I'm ready to call it done at this point, so I'll let you know in a week or two how it turns out!

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AGHRMattAGHRMattOGR Forum Member SUPPORTING MEMBERMEMORIAL SUPPORTER
Mike DeBerg posted:

Eric,

Really great work!     

Definitely looking forward to getting a couple of these to test them out!   Will be waiting to hear/see about your initial results!

I have a couple Indiana Railroad SD9043's!

I can hardly wait. I'll be able to do this consist again (sold the hi-rail Bush 41 when I bought the scale-wheeled Proto-3 version):

Picture 002

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T thor73OGR Forum Member

Hey, if anyone has the newer SD90 models, could you post a couple pics of the underside and chassis? Here is what mine looks like:

IMG_5626IMG_5619

I noticed as I was taking measurements on my ES44AC that the chassis and shell have features that I assume are there to accommodate mounting of the 2-rail pilot:

IMG_5717IMG_5759

Just curious if the newer SD90 models are set up like that as well.

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T thor73OGR Forum Member
Mike DeBerg posted:

Hi Eric,

Any updates from the first run of these conversion pilots?

Yep, the parts arrived while I was on vacation last week. I haven't had a chance to go over them in detail, but a quick fit check looked promising:

IMG_5885[1]

BTW, if you are ever in the Denver area, be sure to check out the Georgetown Loop Railroad. They have an operating Shay locomotive as well as a few diesels. http://georgetownlooprr.com/

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Tags: MTH, Kadee Conversion, pilot, coupler, SD90MAC
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