Another Structo Dump Truck Conversion

[Rvjimd]

I got a good start on my first dump truck yesterday. I'm try to use some of the drivetrain and suspension parts from a donor short course truck I had.

Just checking the edit function, I still need to find a new place to host and link my photos AND try to download all my photos from Photobucket...


Jim

[Rvjimd]

Starting on the front end, this might be harder than the read end, I'm going to try and make it a 4x4. :confused:

I thought this shot was worth the tall part in the mill vise clamping solution...

http://i1291.photobucket.com/albums/b554/Slotcarjim/66590dc279efdc32c9700ba1d9e22769_zpsvtvd2nms.jpg

Jim

[rc_farmer]

I remember that truck with the pneumatic cylinder, good conversion

[frizzen]

That's looking like a really good start.. It'll be really interesting to see how your truck comes together.

What was the short course donor?

[Rvjimd]

Friz, the donor is a dromida. I'm not convinced it will be the best donor, but it is what I had on hand. It is pretty cheap and mostly plastic parts like all the diff and shafts and stuff. It will be interesting to see how it holds up if I get it going!

Here is a related video I just posted about the gear head motor I am using in the truck. I screwed up and used a mounting screw just a bit long and it busted a tooth off one gear in the motor.

http://youtu.be/HsCEJ2fIEKM

Jim

[Rvjimd]

Got some more done this weekend. I am going to have to fine tune the chain drive/transfer mechanism. It doesn't line up well enough the way I have it and the chain binds up on the sprockets more that I want. I also need to come up with a descent tensioner for the chain. Problem is, I'm using the same mounting screws from underneath that attach the steering cross link and Bellcrank system.

http://i1291.photobucket.com/albums/b554/Slotcarjim/99F2EB52-CA31-4424-AE98-F27E0FC35F2D_zpsyw577syz.jpg

Jim

[modelman]

Good start jim!! Where do you find these metal toys?

[Rvjimd]

Tom, thanks.

I found one dump truck at the pike steam show a few years ago and I found one local here at a antique/consignment shop. My dragline came from a local diecast toy store, it was a lucky find.

I'm hoping to find something at the steam show this weekend.

Jim

[Rvjimd]

Going a different direction with the drive train and suspension on the truck. Here is the proto rear axel ready for milling hex on the ends to fit my wheels.

http://i1291.photobucket.com/albums/b554/Slotcarjim/8BCF93DF-42A9-41E9-BE95-3AD6A936E90A_zpsabg43rdz.jpg

Jim

[modelman]

Jim-what,s your plan on milling the hexes on the ends? I have been thinking about doing this on my dragline walking system but I don't know how to do it and keep the ends matching without an indexer. (I think that is what I need), but I am just in the thinking part right now. May never happen.

[Rvjimd]

Tom, I found two hex nuts that fit close onto the shaft. I drilled through the flat of the nuts and taped them for set screws on opposite side of each nut so I can attempt to evenly tighten the nuts just to try and keep them reasonably centered on the shaft.

I laid the assembly on the surface plate as I tightened the nuts to keep them parallel, although for my case I don't think it would really matter that the hex on one end is in the same plane as the other end.

Then I simply laid the shaft with nuts attached into the mill vise and milled one flat, then rotated to the next flat on the nut.

http://i1291.photobucket.com/albums/b554/Slotcarjim/e12bf3cc0a0762d33db97b08bccf93a3_zpsygcmez79.jpg


Jim

[Rvjimd]

Once I figured out how to do the hex I decided to go big. So, I'm making hubs for the wheel with the hex and a flange that looks like a brake rotor. That pulls up against the inside spokes of the wheel with a 6-32 cap screw to keep it parallel with the wheel. Then I drill the inside of the hub to fit a 1/4" steel axel.

Hex milled on the mill using a slip fit nut attached to the round. Then moved to the lathe to turn the rest.

http://i1291.photobucket.com/albums/b554/Slotcarjim/97D0CD3F-2949-4A28-AF9C-866FAE2310DC_zpsv23karoj.jpg

Turned down and parting it off here.

http://i1291.photobucket.com/albums/b554/Slotcarjim/FC0048FD-2FCF-437E-8D2F-189C1756A110_zpspxy0hqlm.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/B68D4044-1AC1-42C6-8061-2C01D50C6FE1_zpsrzdvycma.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/DF9E1F51-5ABC-44B1-87F8-7CA85F705071_zps7uupldal.jpg

Jim

[frizzen]

Independant suspension, coilovers, alloy super-singles, brake disks... somebodys building a Sports Dump Truck!

Looking really cool so far. I can't wait to see how it turns out.

[Rvjimd]

:p ya, you might get that impression huh? :p the coils and independent suspension is going away and the disc brakes which probably aren't typical are mostly for my machining experience/practice and to try and give support to the plastic wheel. I plan to make my own rims if I ever get this sucker powered up and working with the "borrowed" plastic.;)

Jim

[Rvjimd]

Here is my version 2 prototype rear axel. Thinking about how to do the halves from the gear cover out to each wheel. I want to do a "typical" style solid axel with leaf springs. :rolleyes:

http://i1291.photobucket.com/albums/b554/Slotcarjim/D979D0DA-FFD0-435A-950A-051F11E6DAA0_zpscng4iwkc.jpg

Jim

[modelman]

Jim-looks like you, the mill and lathe are getting along nicely. They can be lots of enjoyment and you can make about anything your mind can come up with. However, after cranking those handles for a long time it can get boring. That's why new projects are important. Truck is coming along good!!

[Rvjimd]

Trying to figure out how to make the mesh a bit more/easier to adjust.

http://i1291.photobucket.com/albums/b554/Slotcarjim/D6B659B8-C731-4DE2-BAD0-75392361B08D_zpskucx2md0.jpg

Jim

[frizzen]

Without knowing your plan for that axle, but thinking about gear mesh. It looks like you're thinking both bushing and bearings.

Would it work to thread half of the axle shaft so that you could run 2 thin plain nuts in a jam configuration on the right of that picture where the bearing is currently, to pull the mesh tight. Maybe do that on both sides for an easy adjustment of mesh and backlash.

Or a more difficult but much cleaner install could be milling a flat inside the pumpkin where the base of the crown gear sits, so that you can just shim the crown gears together. It'd be more annoying to set up, but your axle tubes could be thinner and it won't weaken the shaft like threading would.

[Rvjimd]

Dump Truck Conversion Take Two!

Got myself a donor with solid diff/axels and started over on the dump truck.

Here are the leaf springs and shackle so far. Leaves are made from steel strap and shackle parts are plastic chain links and aluminum channel.

Springs are about 3.5" eyes, might change once I get further into it and see how it sits.
http://i1291.photobucket.com/albums/b554/Slotcarjim/87F6CD47-25AE-474C-B9AE-C3F4DAB5DC63_zpsd30v9fix.jpg

Planning to use brass tube for the pivots
http://i1291.photobucket.com/albums/b554/Slotcarjim/7657B489-1DF6-44F8-B84D-4E41BCD5D6B1_zpsi26vrup1.jpg

One shackle...
http://i1291.photobucket.com/albums/b554/Slotcarjim/66344B26-BD8F-4E18-8C1C-32A1E0964E66_zps4iluenuo.jpg

Stay tuned.... :rolleyes:

Jim

[Rvjimd]

Going to try a single helper and using heat shrink as a keeper
http://i1291.photobucket.com/albums/b554/Slotcarjim/08F4382A-BAD4-4E49-9221-4B59BF31CB89_zpsngjsgkuc.jpg

Axel mounted
http://i1291.photobucket.com/albums/b554/Slotcarjim/3B53DAAD-F888-49F5-B8FF-7C3B11C40B3F_zpsjgwb05dr.jpg

Now I need to figure out how to solve the wheel and hex size mismatch. I have some wheels I plan to try but the hex is smaller than this one here.
http://i1291.photobucket.com/albums/b554/Slotcarjim/DCC684F0-D30F-491B-8F50-4EC9E393C712_zpsjbrvzqzk.jpg

Jim

[frizzen]

Aww, no more sports dump truck?. Looks like a good restart!

I like the spring hangars, but that shackle may limit the suspension movement. If you want more suspension articulation later, you can often swap the brass leaf bushings for a piece of silicone fuel tube/aquarium air line.

The rear pinion angle looks good, how does everything feel with some weight on it?

What size hexes do your new wheels have?

[Rvjimd]

The wheels I want to use are smaller than the redcat hex. My wheels are from a dromida sct, and the size, tread and wheel style are all pretty good look for a dump truck.

I remember seeing fuel line bushings, is that so there is some give and flex? My brass bushings are pretty loose.

The springs seem okay, but haven't really tested it yet...

[frizzen]

Brass bushing gives you vertical travel as the leaf moves, but binds when tolerances close with off axis movement. With a solid axle say left wheel is on bump, right is drooped, the shackles pinch leaf and stop travel. Sloppy tolerances let it rattle around and flex a lot. Soft bushing gives more travel, some damping. It's more of a rock crawler trick, like tapering the leaf eyes so you may not even want or need it.

Looks like your rim uses 8mm hex. So maybe... thttps://www.amazon.com/gp/aw/d/B01NBASGBG/ref=mp_s_a_1_9?ie=UTF8&qid=1493598059&sr=8-9&pi=AC_SX236_SY340_FMwebp_QL65&keywords=8mm+hex+wheel+rc

[Rvjimd]

I made adapters for the hex, I'm not sure I saw anything off the shelf to go from big to small? Got the rear axel mounted, I think I'm gona need another helper and a tweak to get it right. Now to the front and mount the transfer case.

http://i1291.photobucket.com/albums/b554/Slotcarjim/90B09516-D900-4300-9614-F44FE57981E3_zpshue6itzn.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/516737C3-87EC-460B-B24A-73890B0C0B11_zpsxyaszgoi.jpg


Jim

[frizzen]

They usually don't do big to small hex adapters, you just replace the big hex with one your new size that fits the shaft and cross pin.

Looking good, but I might move the aft spring hangar back a little, the shackle looks like it doesn't have too much travel before maxing out that spring. I had issues with shackle flip on some big bumps like that.

[Cooper]

Hey Jim, thanks for sharing that idea you had with the nuts to mill the hex sides. Pretty good idea. I've been wanting to get some 5c collets just so I could have the collet blocks for hex and square sides but that bolt idea is clever.

[Rvjimd]

Cooper, the hex nuts worked better than I expected, but the size was a good match for the stock so it helped center the round stock. The set screws keeps the stock from rotating inside the nuts. And, since you have to release from the vice and rotate, you have to use a stop or something to index the part for the subsequent operations.

Short version of this story, I ended up buying a spin indexer and 5C collet set! ;)
It is much quicker since you don't have the vice issues to deal with.

Jim

[Rvjimd]

Got the motor/transfer case mounted, but I think I'm gona move it back about half an inch to make the front drive shaft fit easier. The front springs are ready.

http://i1291.photobucket.com/albums/b554/Slotcarjim/D8902BEE-C496-405F-BA19-D0643FE77FF3_zps2gqzjdnc.jpg

Jim

[frizzen]

Looks like yours is this the 1964-65 version.
http://www.tnttoytrucks.com/Structo603.html

Ane you hanging the trans below the chassis?

[Rvjimd]

Ya, that's where it is for now. Doesn't leave much clearance but helps with the angle of the drive shafts.

[Rvjimd]

Finally got back to the dump truck project. Decided to move the motor/transfer case up a bit to improve the ground clearance. Now I have to figure out what to do with the front drive shaft? It is pretty short and has a pretty steep angle.

http://i1291.photobucket.com/albums/b554/Slotcarjim/5ce308d420acb161298b766006dd00e2_zpsdjw27h0b.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/b681a3747168836aceca9e36302564d8_zps42umlel5.jpg

Jim

[frizzen]

Looks like it's coming along well.

Got a pic of the front driveshaft angles? You might be able rotate the trans off center to stretch the front shaft some.
What does your breakover angle look like with the trans that low?
Does the spur gear interfere with the cab? I ran mine spur fwd for a little more clearance.

[Rvjimd]

I checked the cab clearance several times and I think I'm okay, got it as far aft as possible. If the power comes back on tomorrow I'll be back in the shop...

[Rvjimd]

Making a few U joint parts, gona be able to make a new simple drive shaft that will use a pin and slot to allow it to float.

http://i1291.photobucket.com/albums/b554/Slotcarjim/68FCA2CD-D024-410D-B721-790004F17615_zpsuuk0fviu.jpg

Jim

[Rvjimd]

I'm getting close to having an actual operating dump truck! It goes and steers, I don't have the front drive shaft hooked up yet, need to make a drive shaft.

Got the lift mechanism working, need to tidy up a few bits and test it with some weight. Looks to me like the speed is about right, got lucky with a motor I had on hand.

https://youtu.be/b-pTdpjsn_M

Jim

[Rvjimd]

Here are a couple close up pictures of my dump bed lift actuator. The screw is 10-24 all thread about 1.5" long. The push tube is made from 3/8" delrin solid round. I drilled and taped the first 3/8" to be driven by the all thread screw and the rest of it is clearance drilled to reduce the friction load on the motor since the entire tube doesn't need to be threaded. The motor is from servo city and the mount is a piece of square stock that I milled to allow the motor to fit out the top and there is a slot at the front that keeps the assembly from rotating. There is a screw/pin at the front that keys into a hole in the truck frame to keep the assembly from sliding back when the box is up past the balance point where it wants to pull on the screw and motor pod. I used a set screw on each side to hold the motor in the mount. The coupler is made from 3/8" aluminum with two set screws to hold the screw shaft and lock to the motor shaft.

http://i1291.photobucket.com/albums/b554/Slotcarjim/91ADEC0A-E6F7-42E2-BB38-4D7D1B883A14_zps30ej3pmw.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/7C186DF7-DDA7-4720-A1CF-FF71BB303E16_zpsvrvxb4gd.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/F95EE9A8-152A-44A1-9200-D4EBDF026470_zpseyvqroc4.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/C8E047FD-27E2-4FAC-AD39-BA5095948DA0_zpszizewth5.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/0F83D895-1503-4FF1-A59B-0D24BDE669F6_zpskcafkupt.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/65E1C3EA-BB55-4378-BDF8-AF69F47B06A3_zpsvirqjczy.jpg

Jim

[frizzen]

Pretty slick bed actuator.

[Rvjimd]

I made a little details video of the actuator on the truck.

https://youtu.be/XSUyETpCy9M

Jim