Mack 45 ton switcher

[peteski]

I'm never gonna be able to blacken like a Kato wheel.

You do have a point there.  I'm also surprised that this tiny loco has 40" (or is it 42"?) diameter wheels.

[mmagliaro]

Sorry I don't want shiny treads. I really dislike those wheels. Kato wheels are already in the mail. Just need to make a few tweaks to my chassis to fit those wheels.

Have a bunch of Kato wheels, but their gear is offset to the side and I doubt they are 0.2 mod.

Toma Model Works makes the same type of wheelsets with 0.2 gears and blacked wheels, but he doesn't list them separately.

The Kato wheels for their "mid production" SD40-2 have a mod 0.2 20 tooth gear centered on the axle tube. 

[Chris333]

So I have a little bit of time to design the chassis. Lets work on just how big this thing was.

This is the only drawing I have


Mack only made 21 locomotives ever and very few were 6 wheeled. The above drawing doesn't match anything I've seen a photo of. There are a few perfect side shots though.


And this one that I "traced"


Just using the 3 above photos. What is the length of the locomotive and what is the wheelbase? If I size the photo so it is 21'2" long then the wheelbase doesn't match. If I size the photo to the wheelbase the locomotive ends up about 4' longer than the drawing lists.

Any ideas?

[mmagliaro]

Given that the size of the wheels agrees with the wheelbase if I scale between the two, and also given that the drawing shows the body shape a little differently than the actual photos, and further given that the measurement between wheels 1-2 and 2-3 is almost dead-on the same (implying that there isn't much perspective distortion from the photo), I am inclined to believe the wheelbase measurement, and then conclude that the actual engine was built a little longer than the drawing.

[u18b]

I would say the photo and the loco are clearly two different locos.
Remember, the drawing loco may never have been built- lots of examples of that.

At any rate, it is probably a safe bet the TRUCK is the same as the drawing.  So scale your drawing and photo to match the 13' from outer wheel to outer wheel.
Then just go by the photo for the shell dimensions.

I encountered some of this confusion with the Tractive Power TP56 series.
Even to this day, the "drawing" that TPC has on their website is NOT the TP56 that they build- the drawing is shorter and reflects the first (or prototype) that they built.
It took me a while to realize that the unit I wanted to build was NOT the loco in the drawing.

edit:  Max beat me to the same conclusion.

[davefoxx]

I agree with Max and Ron.  It looks to me like there is more distance between the edge of the wheel and the pilot in the photo than in the drawing, making up most, if not all, of the four feet of increase in the length of the carbody.

DFF

[JeffB]

Chris...

Doesn't the Polish company we buy our gears from have 0.2Mod 15t worm gear/worm gear sets?  Using those on the axles, with the 12t set up off the motor would lower your overall ratio down to 180:1.  Enough of a reduction to matter, but probably not as much as you'd like.

Jeff

[u18b]

Chris....  I would also extend the center section with the headlight a bit.

Remember, because farther things are rendered smaller.... and because the central section is farther than the outer edge, then in the photo the central section appears smaller than it really is.
How much?  It's a guess, but I would fudge it a little bigger.



In fact, your drawing extends on the right side.  I assume that you drew the left side perfectly, copied and pasted and flipped for the mirror image on the right side.   But since the drawing does not match the photo on the right side..... that shows...
the photographer was not standing dead center to the center wheel, but was standing slightly to the right of center (and you can sort of see that).   That small change in positioning made a significant effect in the appearance in the photo.

As another proof... look at the bottom edge of the pilot and how angled it appears.

[Chris333]

Few more photos:
http://www.northeast.railfan.net/images/lv111.jpg
https://www.bigmacktrucks.com/uploads/monthly_11_2013/post-16320-0-20023000-1385536064.jpg
http://members.trainweb.com/bedt/indloco/bxtlv50.jpg
https://rrmuseumpa.andornot.com/media/Images/GenNeg/GenNeg-16500-16999/GenNeg-16869-cat.jpg?maxheight=1000&maxwidth=1000&watermark=wmk
https://rrmuseumpa.andornot.com/media/Images/GenNeg/GenNeg-16500-16999/GenNeg-16871-cat.jpg?maxheight=1000&maxwidth=1000&watermark=wmk

Post this 4 wheel one because it uses the same type of body:
http://www.northeast.railfan.net/images/cbq100.jpg
http://www.northeast.railfan.net/images/pot2.jpg

[Chris333]

Chris....  I would also extend the center section with the headlight a bit.

Remember, because farther things are rendered smaller.... and because the central section is farther than the outer edge, then in the photo the central section appears smaller than it really is.
How much?  It's a guess, but I would fudge it a little bigger.



In fact, your drawing extends on the right side.  I assume that you drew the left side perfectly, copied and pasted and flipped for the mirror image on the right side.   But since the drawing does not match the photo on the right side..... that shows...
the photographer was not standing dead center to the center wheel, but was standing slightly to the right of center (and you can sort of see that).   That small change in positioning made a significant effect in the appearance in the photo.

As another proof... look at the bottom edge of the pilot and how angled it appears.

I know the photo isn't perfect and the tracing I did was just the starting point. Once I got it into 3D I would position the 3D model with the same perspective as various photos and toggle back and forth between the two. Then make tiny changes to anything that didn't look right. Even used a Youtube video to get the cab end radiator openings to look right. The radiators are on the roof and looks like a water tank down the center.

I will be OK if every scale inch is not correct considering how little info is available, but just wanted to make sure I wasn't wasting my time with what I had. I did resize one print so that is was 21'2" long and it just looked way too tiny. More the size of a GE 25 tonner. I know size is different than weight, but this is a 45 ton locomotive.

[Chris333]

Guess I'm set on the size. I scaled it down a hair more so they body is now 23.64' long and the wheelbase will be 6.1'. Here is what that looks like next to a Bmann 44T.


And you may notice on my original prints there was a ripple right above the bottom of the side window seen here.


I tried a bunch of stuff to get rid of that. It is there because of the flat surface on top of the hoods. Nothing worked to get rid of it so I just deleted the hood tops and that worked. Now the tops will be printed separately and glued on. This is the newest print.

I also changed the cab end windows to better match.


Please send help!   

I just ordered another 2 liters of resin.

[Chris333]

Sideframes mocked up and the correct diameter wheels shown




With all the resizing I now need to push the motor back about .040".

[Kentuckian]

Really cool! How do I order? 

[JMaurer1]

Isn't that why so many people print things at an angle? To keep the surface tension from large flat areas from causing lines?

[Chris333]

Isn't that why so many people print things at an angle? To keep the surface tension from large flat areas from causing lines?

Yes that is correct. But printing at an angle creates other problems. Like if I tilted it up the main point would be the very thin footboards on the pilots. And there would probably be supports attached to parts you'd see. The way I did it printing flat all the supports are under it and when I literally rip them off the tiny dimples will never be seen leaving all the areas you see nice and crisp. When I print a steam locomotive at an angle I build in a tab at the lower rear of the cab to be a big foot contact area that will later get cut off.

The only possible way I see to print this at an angle would be to split it in half, print 2 ends, and glue it together. But then the ends at the splice might bulge out a little and make the joint look wonky.

There is nothing set in stone with printing. You just know how it works and try to guess the best way to go.