M-9 45 Ton Trailer Build

[Chariots of Fire]

Work has started on building the trailer for the M-20 Prime Mover.  First thing up is to do all of the tires and wheels that are needed.  24 in all.  8 in the front steering section and 16 under the rear of the trailer.  I'm using 1/32 scale metal castings for the wheel masters and a set of Goodyear rubber kit tires for the tire master.  They work out to be about right for 8:25 x 15 tires that were used on the M-9.

IN the background is a mold for the wheels and with the rubber tire masters set up on a pair of the cast wheels that came from the rear mold.  In the foreground is the tire mold with the cured resin tire castings still to be removed.  

All 24 tires and 12 wheels have been cast.  The wheels are sufficient to mount two tires on.  The backs won't be seen at all once they are mounted on the axles.  The wheel centers need to be drilled out for brass bushings.  That will come a little later once I have figured out how each axle is going to be made.  

The frame has been started.  The Tankograd photo publication has some specs with it for the overall length and width of the trailer.  The towbar is an additional 6 scale feet above and beyond the full trailer length of 290 scale inches.  There is an additional scale 40" in length to be added to the front of the trailer side beams.  All of the work so far has been done with 0.030" Evergreen sheet plastic and 0.030" and 0.020" Evergreen strip stock.

A look at the side view with the wheel placement.  The front 8 tires will pivot with a separate plate that the axles are mounted on.  It is a box type detail that fits under what is shown beyond the side frame.

Here's the bottom side.  Still incomplete but well on its way.  The two open sections are where the spare tires will be stored.  Additional longitudinal bracing has to be added as well.  All of this work is held together with CA glue.  It was very flimsy to start with but it got stronger with every added piece of plastic stock.  The two driving surface plates on top really made a difference.

The two raised sections on the left are the stops which keep a tank or other piece of equipment from rolling off the front of the trailer.  There will be plenty more to come before this build is finished.

[Jürgen M.]

Wow! That's gonna be a nice build! I'm watching! 

[The Brush]

Nice moulding of wheels & tyres. I built one a few years back using the techniques, Good build to follow.

[Rockford]

Absolutely fantastic stuff. 

[yh70]

thats looking Great.

[Ace-Garageguy]

Always a treat to follow along on these builds of yours.  

[hct728(Bob)]

I see where that big Prime Mover was about the only thing strong enough to haul this beast, LOL!

Edited October 17, 2024 by hct728(Bob)

[Chariots of Fire]

Got a bit more done on the trailer.  The front axles and frame have been quite a bit of work.  The more I studied the photos the more I saw.  There is still more to go but this is where we are as of today.

I made a master for the front axle supports from strip stock.  First was to make a template for the web which was made solid.  The flanges were then glued to the top and bottom edges.  Then the interior braces were cut from strip stock and glued to the web.  Once that was done holes were drilled in the web to create the open spaces.  Tubing was added to each end and at the center bottom.  It was enough to make just one but to make a second one that looked the same and had the same dimensions would have been a challenge.  So back to the mold again to make two copies.  Once cured, the thin flash was easy to remove from the openings.

Here are the two axle frames mounted on strip stock and sheet stock platform that will form the pivot for the front set of tires.  Details were built up with strip stock, some small springs and additional sheet stock.

This is what the bottom side looks like.

The tires and wheels go on each side of the axle frame.  The hard part is going to be getting the inside tires in place and secured.  I first tried holding them on to the axles with screws but it is impossible to get the inside screws in place due to the close spacing of the inner tires.  Got to get the thinking cap on and the little gray cells working.

The front tires and assembly in place on the trailer.  The platform of the trailer is supposed to be about 38 scale inches above the ground.  It came out about right.

The brackets for the tow bar will be attached to the box that is just above the tires.  There will be two brake wheels; one in the front center of the box and one sitting upright on the small platform on the front left.  There are sixteen tires and wheels left to make axles for in the rear.  There are two tandem axles to construct and get mounted.

That's it for now.  Back to the study session to see what's next.

Sooner than I thought, the axle problem is solved!  Since I can't get the inside wheels in place and tighten a screw on the hub to hold the wheel in place I substituted a different solution.  The axle consists of the bushing or sleeve that is in the wheel, the axle itself in two pieces and an inner rod that with be epoxied to both ends of the two part axle.  I'm using telescoping tubing so I can slide these pieces inside the wheel easily with a good fit.  The axle on the inside wheel has an outside soldered hub that will secure the wheel in place.  The rod will be epoxied to it.  If I use a small amount of two part epoxy on the rod and slide it back and forth inside the axle, I can bond the two pieces of the axle together.  The outer axle half has a similar hub on it to hold it in place with a dab of epoxy.  All of the wheel sets will still be able to turn.

Edited October 25, 2024 by Chariots of Fire
added comments

[BK9300]

I agree with Bill - a pleasure to follow along with, as well as demonstrations of skills I could do well to learn.

[Biggu]

Another EPIC build. !

[hct728(Bob)]

I'm amazed at the precision molding and assembly of the suspension and wheels! From the front it's really looking like the prototype. That said, it must have made a bit of noise going making a turn on pavement with all that rubber squealing in distress, LOL!

Great progress, save some work for the shut-in winter months too!

[Chariots of Fire]

2 hours ago, hct728(Bob) said:

I'm amazed at the precision molding and assembly of the suspension and wheels! From the front it's really looking like the prototype. That said, it must have made a bit of noise going making a turn on pavement with all that rubber squealing in distress, LOL!

Great progress, save some work for the shut-in winter months too!

These rigs were not very fast, Bob.  23 mph was top speed for the prime mover.  They probably did wear out a lot of tires though.  Tire pressure was noted on one photo I saw as 115 lb!!

[Gary Chastain]

Your skills are top notch, impressive 

[Randy D]

Always lessons to learn from your builds Charles!

Wonderful work,

Randy

 

[Chariots of Fire]

The trailer is now up on wheels.  Was able to complete the basics of the rear trunnion and axle assembly for the 16 tires and wheels.  The information was a bit sparse but when the trailer is finished most of the work won't even be seen unless the trailer is turned upside down.  Still plenty to do but a but part of the build is now behind me.  Now on to some of the other details!

The two brake wheels and assemblies need to be made for the front.  Also the sheaves and rollers for the cable are needed.  Spare tire racks to underneath in the center opening of the frame.

Brake rods and air cans are installed on the back of the front axle bracket.  The rear tires float in both directions so that there is always pressure on each tire, even on uneven ground.  The trunnion allows movement from front to back and the swivel axles allow rotation of the four sets of tires from side to side.

Rotation is obvious here with the front set out of apparent alignment.  The tires are not on the wheels yet and won't be until after they are painted.  I can still separate all of the parts for painting the under side of the trailer and all of the axle parts.

The tow bar was made of brass.  Each one of the small lifting handles was soldered in place.

The prime mover and trailer.  The trailer is wider than the truck and is longer.  Makes for a long display shelf when all is said and done!?

[Biggu]

Wow this is a real tutorial in engineering and scratch building. This is fabulous and the bar is raised once again. Terrific update…… incredible workmanship. 

[hct728(Bob)]

Neat work on the tow bar, takes some skill to solder the many elements! Trying to think of the term for the rear suspension, "freedom of motion in three planes" or something similar, and you've done it, impressive!

[Chariots of Fire]

Got a little bit more done on the front end.  The underside of the trailer is now painted but the top won't be done until I've figured out all of the stuff that needs to be included.  Brake lines and levers, the spare tire rack, all need to be put in place.  Anyway here is what the front end is beginning to look like.  Some things are just set in place until final painting of the trailer itself.

[BK9300]

I really like the brass work and all your detailing is very meticulous!

[Rockford]

Very realistic work. Well done. 

[hct728(Bob)]

Looks like that mail-order watchmaking course in Popular Science paid off! (remember those?) LOL

Same skills, anyway! Such neat work, and no detail missed, well done!

[Chariots of Fire]

Work continues on the front of the trailer.  Two air lines have been added and the front portion has now been painted.  Latest project was to make to double sheaves that will rest behind the air filters on the bed.  They have turned aluminum pulleys and brass work for the rest.  The brackets need to be added to the trailer bed to secure them in place, although they were intended to be removed for recovery operations.  Still needed are two lifting handles for each one.  The real ones are heavy!!

[Biggu]

What talent ! How do you make the sheaves so clean and accurate ? Incredible. Absolutely beautiful fine detailed work. Real eye candy ! 
 

Jeff

[Chariots of Fire]

14 hours ago, Biggu said:

What talent ! How do you make the sheaves so clean and accurate ? Incredible. Absolutely beautiful fine detailed work. Real eye candy ! 
 

Jeff

I started with a pattern which I taped to some brass sheet.  Then cut each piece using a dremel and cutting disc.  Before cutting, holes were drilled in the center, at the base and top in the first one so that it could be used as a pattern for aligning the holes in the other pieces.  When pins were inserted in the center hole and one of the other holes, it served to secure both pieces so the remaining holes could be drilled with some precision.  When this was done three pieces of brass were held together by the pins and then clamped in a vice grip and the edges of the pieces smoothed up to be the same.  It was a bit tedious, but the results speak for themselves.

[Biggu]

Precision is the word on this build. And yes the results more than speak, they scream. Beautiful craftsmanship and it takes a real craftsman to make such excellent pieces …. More than a joy and pleasure to watch come together. 
 

Jeff