12/13/2008
| FLEXICOIL TRUCK MODELING THE ONE UP/ ONE DOWN BRAKE CYLINDER SETUP |
When I first embarked on this project I thought "building these truck side frames would be a piece of cake. Just
take a low mount, cut out the brake cylinder and mount a brake cylinder up high". WOW, was I wrong!!!!!!!!!
To build this type of truck requires the modeler to completely rebuild the entire brake rigging area. Cut
everything out and start from scratch and that is not the half of it either. There is another little known tid bit that
makes this conversion even more tedious. Let me just say, fat fingers will be a hindrance. I will get into all that
very shortly.
The truck set you see pictured above is for my CONRAIL ex-CNJ SD40. The gear box is Kato and the
sideframes are from Athearn.
BILL OF MATERIAL:
- Kato SD40 or SD45 truck set. Can be high mount or low mount, does not matter since all teh brake rigging will
be cut out
- Athearn low mount side frame set #40066
- Athearn high mount side frame set #40070
You get the brake cylinders in the high mount set.
New pins will need to be built to mount the Athearn side frames into the Kato gear box. I'll explain that in this
article. Also to allow the trucks to swivel inside the Kato step well, 0.020" needs to be taken off the leading edge
(edge facing step well) of each side frame. As you can see in the photo above, you cannot see thatl this was
done. In fact if I did not say anything, you would not be able to notice it, but it needs to be said in order for this
truck set to work properly.
There is one big advantage of using the Athearn side frames. They look SO MUCH better than the Kato side
frames. You can't see it here, but when the truck is mounted under the model, you can really see the
difference. When I build my SD45 with all low mounts, I am still going to put the Athearn side frames on it as
well. They really look that much better!
take a low mount, cut out the brake cylinder and mount a brake cylinder up high". WOW, was I wrong!!!!!!!!!
To build this type of truck requires the modeler to completely rebuild the entire brake rigging area. Cut
everything out and start from scratch and that is not the half of it either. There is another little known tid bit that
makes this conversion even more tedious. Let me just say, fat fingers will be a hindrance. I will get into all that
very shortly.
The truck set you see pictured above is for my CONRAIL ex-CNJ SD40. The gear box is Kato and the
sideframes are from Athearn.
BILL OF MATERIAL:
- Kato SD40 or SD45 truck set. Can be high mount or low mount, does not matter since all teh brake rigging will
be cut out
- Athearn low mount side frame set #40066
- Athearn high mount side frame set #40070
You get the brake cylinders in the high mount set.
New pins will need to be built to mount the Athearn side frames into the Kato gear box. I'll explain that in this
article. Also to allow the trucks to swivel inside the Kato step well, 0.020" needs to be taken off the leading edge
(edge facing step well) of each side frame. As you can see in the photo above, you cannot see thatl this was
done. In fact if I did not say anything, you would not be able to notice it, but it needs to be said in order for this
truck set to work properly.
There is one big advantage of using the Athearn side frames. They look SO MUCH better than the Kato side
frames. You can't see it here, but when the truck is mounted under the model, you can really see the
difference. When I build my SD45 with all low mounts, I am still going to put the Athearn side frames on it as
well. They really look that much better!
Here I am simply showing the as modeled Athearn low mount side frame. It has some good depth of detail to it.
There are some problems with it. Some have to be overlooked while others will need to be changed. The one you
have to overlook is the casting EMD stamp and the circled C stamp on the side frame. Athearn only made one of
these frames. On the prototype, the stamp is not in the same place on both sides. Check your prototype and you
will see this.
The next problem needs to be fixed and is very easy. You see the brake clasp bracket that runs between the
journal castings. It is much to low. This bracket needs to be about center on the journals and at about the top of
the brake cylinder.
There are some problems with it. Some have to be overlooked while others will need to be changed. The one you
have to overlook is the casting EMD stamp and the circled C stamp on the side frame. Athearn only made one of
these frames. On the prototype, the stamp is not in the same place on both sides. Check your prototype and you
will see this.
The next problem needs to be fixed and is very easy. You see the brake clasp bracket that runs between the
journal castings. It is much to low. This bracket needs to be about center on the journals and at about the top of
the brake cylinder.
STEP #1:
This step is the easiest of all. Clean all the brake rigging off and clean up the frame. It is very possible to
remove the brake cylinder/caliper/braket without braking it. I use a small chisel blade and wiggle it under where
the calipers are attached to the back of the frame. The pins will brake off which is fine, but the rest of the part
will come off in one piece.
Just wiggle a little at a time around the pin and it will all come off.
Cut the mounting pins off (see note above). The spacer pin attached to the bolster bracket can be cleaned all
the way off and flush with the back of the side frame. If you look at the photo closely, you will see the image of
the mounting pin circle still there. You want to see this circle because you need it to locate the center of your
new pin. There is another feature you want to keep. Look closely at where the pin circle is. You will see a raised
rectangle under it. You want to keep this as well.
remove the brake cylinder/caliper/braket without braking it. I use a small chisel blade and wiggle it under where
the calipers are attached to the back of the frame. The pins will brake off which is fine, but the rest of the part
will come off in one piece.
Just wiggle a little at a time around the pin and it will all come off.
Cut the mounting pins off (see note above). The spacer pin attached to the bolster bracket can be cleaned all
the way off and flush with the back of the side frame. If you look at the photo closely, you will see the image of
the mounting pin circle still there. You want to see this circle because you need it to locate the center of your
new pin. There is another feature you want to keep. Look closely at where the pin circle is. You will see a raised
rectangle under it. You want to keep this as well.
NOTE: Only cut the mounting pins off if you are using this frame on a Kato gear box.
STEP #2:
Locate the center of the mounting pin. The way I did it was to mark the four quadrants of the circle and then
using a knife connect the two opposite quadrants. I then used a pencil in order for it to show up better in the
photo.
using a knife connect the two opposite quadrants. I then used a pencil in order for it to show up better in the
photo.
I chose to make the new pin a snug fit inside the Kato gear case. It is larger than the pin on the Kato side
frame. The pins were made 0.066" thick x 0.152" wide. Length from back of frame is the same as the Kato pin.
From the bottom of the frame I measured up to the pin centerline 0.096". I took half of the pin thickness and
added to that to get the upper extents of the pin cavity. To get the lower extents of the pin cavity I took half the
pin thickness away from the 0.096". The width of the cavity is the same as the raised rectangular area you see
the cavity box drawn on.
One thing I forgot to do before this photo was taken is to fill the brake cylinder mounting pin holes. You will not
be able to reuse these. I blind drilled them 0.080" diameter and filled them with styrene rod. After the glue dried
I trimmed them flush to the back of the frame.
frame. The pins were made 0.066" thick x 0.152" wide. Length from back of frame is the same as the Kato pin.
From the bottom of the frame I measured up to the pin centerline 0.096". I took half of the pin thickness and
added to that to get the upper extents of the pin cavity. To get the lower extents of the pin cavity I took half the
pin thickness away from the 0.096". The width of the cavity is the same as the raised rectangular area you see
the cavity box drawn on.
One thing I forgot to do before this photo was taken is to fill the brake cylinder mounting pin holes. You will not
be able to reuse these. I blind drilled them 0.080" diameter and filled them with styrene rod. After the glue dried
I trimmed them flush to the back of the frame.
Since I use whatever tools I have at my disposal to make my modeling easier, I used my mill to make the
cavities. I cut them 0.030" deep to get plenty of holding power for the new pins. After milling, I used a very small
chisel blade and finished the holes to square off the corners. The frame is now ready for the pins to be
installed.
cavities. I cut them 0.030" deep to get plenty of holding power for the new pins. After milling, I used a very small
chisel blade and finished the holes to square off the corners. The frame is now ready for the pins to be
installed.
STEP #3:
The pins were made from a strip of styrene. As mentioned above, they measure 0.151" wide x 0.066" thick. The
length is the same as the Kato pin from the back of the frame plus 0.030" to be inserted into the cavity. The
holes were made by measuring the Kato hole and duplicating it on the new pin so it is in the same place in
relation to the end of the pin as it is on the Kato pin.
length is the same as the Kato pin from the back of the frame plus 0.030" to be inserted into the cavity. The
holes were made by measuring the Kato hole and duplicating it on the new pin so it is in the same place in
relation to the end of the pin as it is on the Kato pin.
Install the new pins into the cavities. Make sure the pins are perfectly perpendicular to the frame. To make sure
they stay perpendicular through the drying process, I put the copper pickup strip on and insert the frames into
the gear case with the wheels in place as well. I do not put the bottom clip in yet.
Also in this photo you can see that I have filled the brake cylinder mounting pin holes.
The Athearn frames are the same thickness as the Kato frames except the Athearn frames have much better
looking depth of detail. Because of this, you do not need to make any provisones to sink the copper pickup
strip into the back of the frame. The strip fits up exactly like it does on the Kato side frame. You do have to trim
the copper pickup strip in a couple small strategic areas to hide it. This is not a major task though. Simply install
the strip, scribe a line around the area that is visible, remove the strip and grind off the offending area.
That is all the steps needed to modify the Athearn High or low mount brake cylinder trucks and fit them to the
Kato SD40/SD45 gear case. The Athearn high mount side frames are the same thickness as the low mounts.
they stay perpendicular through the drying process, I put the copper pickup strip on and insert the frames into
the gear case with the wheels in place as well. I do not put the bottom clip in yet.
Also in this photo you can see that I have filled the brake cylinder mounting pin holes.
The Athearn frames are the same thickness as the Kato frames except the Athearn frames have much better
looking depth of detail. Because of this, you do not need to make any provisones to sink the copper pickup
strip into the back of the frame. The strip fits up exactly like it does on the Kato side frame. You do have to trim
the copper pickup strip in a couple small strategic areas to hide it. This is not a major task though. Simply install
the strip, scribe a line around the area that is visible, remove the strip and grind off the offending area.
That is all the steps needed to modify the Athearn High or low mount brake cylinder trucks and fit them to the
Kato SD40/SD45 gear case. The Athearn high mount side frames are the same thickness as the low mounts.