TH407C Telehandler 1:14 scale
 

This project has been on and off for over a decade. It's closer than ever, but in a way i'm starting over. Original chassis in 2014 was brazed together. It worked well, but was not very square. My fabrication tools and abilities have improved a lot. The hand built models on the larger forums are always interesting to follow. I present my own build to you all. I hope this thread will keep me motivated as to not disappoint you all.

In the last incarnation I was able to operate the basic functions of the model. Lift tilt, drive and steer all functioned, but not to full ability. The 4WD was never connected and the hydraulic pump would run pretty hot. Body was only partially done.

https://i.ibb.co/3FrGp6X/IMG-0690.jpg
https://i.ibb.co/h2VR72w/IMG-0689.jpg

That Machine still exists and many parts will be stolen from it. I split a solder seam on the boom years ago which was unrepairable since it was fully painted. The boom was rebuilt, but that showed how wonky the original chassis was. New chassis is slightly thinner material (1.5mm) and now stainless to prevent rust in hard to paint areas. CAD design was adjusted and reordered. Tiny welder did its job well. This time I was ultra careful to ensure components are placed perpendicularly using a machinists square. A few internal plates were added to ease cable routing and prevent a messy look when the boom is lifted. Rear steering was entirely redesigned to help fitment and serviceability. A little lower steer force is the cost when switching to a much smaller servo. Drive was originally N20 gearmotors 1 per wheel. This is preserved, but i will use a left and right ESC channel to allow mixing to slow the inner wheels.

Previous Losi Mini Rock Crawler CVD axles were used, but sadly no longer available. I do have 2 pairs on hand, but fear any kind of breakage. Instead Mini-T CVD shaft might be a viable substitution. Steering knuckles will be redesigned to incorporate. Lastly, The Magom HRC pump produced good pressure, but ran too hot. Start-stop pump operation was difficult because motor torque was too low with the alternate required for fitment. A larger diameter outrunner was sourced: Gartt ML3508 415kv. This is the smaller brother to the Garrt outrunner in my Metal Hobi excavator. It handles low idle very well and build very little heat. I hope for similar results in this machine.

Last generation I hit a roadblock with how to build the tubular cage of the cabin. I want it to be metal despite styrene being much easier. A simple techique used in full scale tube bending was applied to 4mm stainless steel tube. A simple tube bender and a end clamp produced favorable results. Once again the small welder will be used to assemble this structure.

https://i.ibb.co/7zRQGTx/aa-sunbelt-paint.png
Will be painted in Sunbelt rentals scheme.

https://i.ibb.co/vLN8YLx/stainless-chassis-2.jpg
Building 2 identical machines.

https://i.ibb.co/zX3hXZ5/stainless-chassis-3.jpg
Tiny welder did good work. Central tabs will be body worked before paint

https://i.ibb.co/fYC99CZ/welded-boom-as-steel-2.jpg
Boom which was rebuilt 2 years ago. May rebuilt yet again to make incremental improvements.

https://i.ibb.co/mNhBr7c/Hydaulic-pump-motor-Gartt.jpg
Larger Gartt outrunner. Every bit of space was used to fit this. Hole in chassis plate will be sealed from below via access cover.

https://i.ibb.co/8jHQfjh/Chassis-mockup-2.jpg
https://i.ibb.co/HBJzxNT/Chassis-mockup-1.jpg
Current status. Reprinted engine cover with slight geometry change. Shows one tube of the cabin guard. Need to rework CAD model of cabin to allow battery acces via small door. Battery is on order now 2S 4000mah transmitter lipo.

Re: TH407C Telehandler 1:14 scale
 

On to the breakthrough of how to fabricate small tube: I used 4mm annealed stainless steel tube. It's very thick wall ~1mm. Comically expensive so i am looking for alternate sources. This should weld very well and not rust while i work slowly. Cuts ok with a jewler's saw or hand file, but certainly work hardens along the way.

First order of business was to add a clamp to the Dubro style bender. I 3D printed a resin block. It holds tight enough once clamped down with M3 screws.

https://i.ibb.co/KFy2b1N/Bends-1.jpg
Block installed on an aliexpress 4mm tube bender. Likely identical to the Dubro5/32" model. This allows an index point that is repeatable shown as red on the tube

https://i.ibb.co/sv7JtvB/Bends-4.jpg
Print a 1:1 scale pattern of the part to build. Use a test bend scrap bend which the index point was marked before hand. Line up the one leg and as much of the bend as possible. Mark the tube's index point onto the paper template. Repeat for all bend locations.

https://i.ibb.co/K5j4v0n/Bends-2.jpg
Transfer each index point onto the tube one at a time before each bend. Keeping everything in-plane needed a little bit more attention than i gave it.

https://i.ibb.co/jv6QcHt/Bends-3.jpg
End result is cut to length and laid over template. A little hand forming was needed to dial it in. Not bad for a first attempt. Slightly out of plane on the second bend, but workable.

This is reassuring that the tubular body that held me back for so many years can be built afterall. This is starting to light a fire so to speak.

Re: TH407C Telehandler 1:14 scale
 

Don't worry about disappointing us, most of us have at LEAST one or more of those long term projects.

I'm guessing that you had the parts laser cut, is that expensive? A couple of years ago one of the fabrication outfits that I used to work with bought themselves an industrial laser. The presented everybody in the Engineering department at the plant where I was working with their own personalized laser cut and engraved Stainless Steel nametag for their desk, as a way of showing what they could now do.

It's REAL easy to screw up when you're doing multiple bends in a piece of tubing. Years ago I went through a LOT of SS hydraulic tubing when making repairs on hydraulic lines. You don't really notice that you got your bender out of alignment until a couple of bends later. You might want to clamp a reference block onto your tube someplace while you're bending it. That would give you a reference surface to check against when setting up the next bend. If you are doing in-plane bends like that, a couple of 3D printed jigs to hold the tubing and bender in the correct orientation might make things go a little easier.

Don

Re: TH407C Telehandler 1:14 scale
 

Laser cut isn't too bad cost wise. Both chassis were $180 shipped from Send Cut Send. Carbon steel is less, quantity discount starts at qty 2. Used to use a local water jet shop which was a bit cheaper, but an hour drive each way to pick up parts. Started looking at Osh Cut aswell. They have more thin material options around 0.5mm, but look to be a hair more per part.

A reference block on the tail end of the tube is a great idea. Simple and gets me some multiplied accuracy depending how big it is. All my bends will be in plane which makes it as simple as I can.

Re: TH407C Telehandler 1:14 scale
 

Very cool build. I will be closely watching as you progress. Really nice to see a new project being documented like there used to be on this site.

Re: TH407C Telehandler 1:14 scale
 

I know what you mean, it seems like there's only a handful of us that are regularly checking in on the site anymore.

Re: TH407C Telehandler 1:14 scale
 

Great looking chassis! That looks like it'll be a really solid machine

If the stainless tubing doesn't work well, brass might be easier to work with

Re: TH407C Telehandler 1:14 scale
 

Brass is easier to work with, but Blender uses a jewelry welder to stick things together. You can solder brass, but it's crap to try and weld - the zinc boils off.

Steel brake line might work though. It's cheaper, available in a lot of sizes, just about every auto parts store will carry it, and it doesn't work harden as easily as some flavors of stainless will. It won't polish up as nice as stainless though.

Re: TH407C Telehandler 1:14 scale
 

Thanks frizzen

Agreed brass is way easier to work with. Been able to weld a couple parts as brass. Was way tougher. The soot ddmckee brings up is for real. Stainless is a pain to shape. Some specialty hand files work pretty well. Welds like a dream though
https://i.ibb.co/wdcpW01/brass-welded-exhaust.jpg
Best bead I could get on brass exhaust pipe for the zx245.

I'm out of town visiting family for thanksgiving brought the parts with to paint. The green is so thin it barely covers. Too messy to do at home.
https://i.ibb.co/ThvpK5X/painted-chassis-2.jpg

https://i.ibb.co/VCxQPMx/painted-chassis-3.jpg
Nothing is wetsanded or polished. Straight from the can. It'll certainly get scratched up during future build steps. Facets from the stl are visible.

Next step is a more CAD work to add the battery door for the cab and a few metal brackets for the cage. Then lots more parts will be ready to assemble.

Re: TH407C Telehandler 1:14 scale
 

Always wondered how well those little tig machines could do brass. I use a lot of brass but have always silver soldered it. Have you ever tried it with aluminum? Happy holidays.

Re: TH407C Telehandler 1:14 scale
 

Best result with brass would be some weld beads to fixture, then flow the solder over it for more strength imo. Decorative welded brass has been fine.

I had terrible results with aluminum. Tried all kinds of alloys and a couple filler materials. Dialed settings every which way. It has a setting for aluminum so I figured it would be easy. I gave up all together.

Brass and silver solder is tried and true. In a way the nice solder wicking and resulting shape is the most scale result. Fixturing was always hard for me, so I swapped to carbon steel so I could use magnets to align. Worked fine, but I'd usually accidentally solder the magnets to me workpiece. So much time spent waiting for things to cool after one joint made.

Re: TH407C Telehandler 1:14 scale
 

https://i.ibb.co/hBm33sx/outrunner-machined-face-1.jpg
Nothing like cutting up a new motor. Had to skim cut the back face and the outer edge to fit the chassis

https://i.ibb.co/dPssZpd/outrunner-machined-face-2.jpg
Pressed out the shaft using the lathe and adjusted the length of both sides. Ran true once reassembled, but did take a few tries to knock out the metal shavings tangled in the windings/magnets. Silky smooth now

https://i.ibb.co/zxrzqBp/chassis-boom-4.jpg
Smaller motor coupler lets it all fit. Test run had the motor starting up smooth and stayed cool. Bad news is I need another pump for the second machine and the latest models are slightly different.

https://i.ibb.co/vh0yyqd/chassis-boom-2.jpg
Welded up two new booms. Now they're stainless so in inside in raw, but won't rust. Previous Gen boom had weld through primer inside, but it didn't slide smoothly enough for my liking. Also added the continuous surround on the end. First soldered boom split right there when I was wrestling with the telescope. Should be much improved.

https://i.ibb.co/3NJnZRv/chassis-noom-3.jpg
Experimented with some adhesive backed strips of UHMW plastic as a guide face. Works well on the raw inner faces.

https://i.ibb.co/9WgSb6X/chassis-boom-5.jpg
Second set of tires were originally destine for another project, but they may get used here. Shorter but wider with a really nice tread. Wheel fitment will be critical.

Cab cage is waiting on a printed cab shell welding jig.

Re: TH407C Telehandler 1:14 scale
 

Looking like really nice progress!

I like that your setting up the rental machines differently to help meet customer needs. Floatation tires vs High clearance AG tires.

Re: TH407C Telehandler 1:14 scaleto get into a dumore
 

https://i.ibb.co/QdG3rY2/steering-servo-installed.jpg
Rear servo actually fits. Based the chassis of listed dimensions, which was a gamble. Rear servo has way less torque than before in order to improve fitment. Should drive okay since the back end is pretty light. 50-60 oz-in should be plenty.


https://i.ibb.co/6X5F5Dc/axle-shaft-couplers.jpg
Made a set of couplers to attach each wheel's gearmotor to the CVD joint. Previously the bores were just cut with a twist drill. Results were OK. These were brought to ID with a proper reamer. Day and night difference. It's like the right tool matters. Set screws are M2 such that they fit within the 6mm OD. These couplers nearly fit in the axle housing so the exterior must be smooth. Normally I'd mill a flat and drill on my tiny mill. I left it at my folks place since I don't use it much. Instead these were made on a tiny drill press. I've been using the stand up machine at work, but it has too much runout for 1.6mm holes. My sherline mill is too cumbersome to use as a drillpress. For about a year I've been looking for something a little nicer than the harbor freight or home depot grade drill press. The price gap is huge to get into a Dumore or similar. Proxxon was interesting, but I'm not totally sold. For awhile I even planned on another identical sherline mill, but keep it manual to let it function as a drill press and simple mill operations. Decided not to. Instead, the China special. I'm pleasantly surprised with it. Baseplate is just about the size of my hand print. Spindle runs true, motor/belt will be easy to modify later. $80. Anything bigger than 4mm is best done on a fullsize machine. It's a timing belt, so it does not slip if a drill grabs the workpiece. Grabbed the optical centerpunch I've been lusting for from McMaster. Should have done that years ago.
https://i.ibb.co/N2bNMQn/drill-press-1.jpg

https://i.ibb.co/ZGCVGK2/cab-fitment-5.jpg
Cab's overhead protection is coming together well. Did have to re make the slightly out of plane main tube. It just wouldn't fit right. The plastic bottom structure and the little roof were used as jigs to weld it all together. The 1mm anti-intrusion bars ended up being assembled a little differently than I planned. Final 4mm round tube will get welded in underneath them. The square sections are solid stainless. Total pain to work with, but I got it eventually.

Seat steering wheel and driver figure will be added. Thought I had one more Tamiya driver figure, but I can't find it. I'll build the seat to match that figure. Cabin will be open style with not much detail beyond some basic faux controls and guage stickers. No door, or windows. Tail lights will be installed, although headlights are a maybe. Roof rotary beacon provision is already integrated into the tiny roof.

https://i.ibb.co/0BCQddw/cab-fitment-3.jpg
https://i.ibb.co/x22dcsj/cab-fitment-4.jpg
https://i.ibb.co/M731krP/cab-fitment-2.jpg
https://i.ibb.co/T8hc1D4/cabfitment-7.jpg
Boom and telescope both have plenty of travel remaining

https://i.ibb.co/KzdJ6cJ/cab-fitment-6.jpg
No extra room. Receiver will sit on the gray shelf. All the ESCs will need to be in the cabin voids.

Been operating the hydraulics with the big motor. Runs well, but the system is weak. Pressure was 175psi and can be bumped up to an even 200 psi, but is still way weaker than it was last time it ran. Before it would do 250 psi and the lift capacity was way beyond what it could stabilize. I need to pull it all out and bench test it. Off the hip I'm thinking the pressure relief spring is to blame. Teardown will tell.

Re: TH407C Telehandler 1:14 scale
 

Spent some time troubleshooting the hydraulics. Pump would deadhead at 200psi. Valve block would deadhead at 75 psi. One of the unused spools wasn't zeroed. Fixed that and get 100 psi at the cylinder port. Not much change in terms of lift force. I did disassemble this valve block to mill one face for fitment. Maybe I put it together wrong. Dug out my old leimbach 2 spool valve. Same results. Lastly connected a new lesu 4 spool. That reads 125 psi at the port. I do expect some pressure drop in the valve, but not that much. Machine ran well before being boxed up with same hardware except for motor. Cylinders don't leak down. Pulled up old images to confirm I was using small 2mm line to each cylinder with good performance. No foaming of the oil in the tank. Clear lines show no air in the system.

I'm still suspicious of the pump. PRV spring measures at 5.5mm free length. Replacements state 10mm, but the design might be different. They also updated the gears to steel from brass. Mine are dark on the backside of each tooth, but no other damage. Don't have a an alternate pump to test with right now, but is on order. Fumotec valves will kind of fit with some work.

Plenty to do on the body, drive and steering in the meantime.

https://i.ibb.co/Mh5cxrM/hydraulic-valves.jpg
https://i.ibb.co/pJXtWQc/rear-light-brackets.jpg
Made tail light mounts
https://i.ibb.co/RBZ2rjQ/boom-down.jpg
Seat is a high back out of a semi truck for mockup. Looks really good with the boom down.

Re: TH407C Telehandler 1:14 scale
 

Back on the drive line:

Losi MRC shafts are no longer available. Instead of having each machine use a different axle I'll rebuild them both to use MIP MiniT CVD. Stub axle is longer than previous so I'll hide it in a dummy hub. Gives an excuse to swap to lug nut mounted wheels while also tightening up the wheel fitment. Will get a cap over the giant M3 nut

One aluminum hub took me way too long to cut myself, so I farmed it out for a reasonable rate. 12 hubs are in hand. Nicer than i expected.

https://i.ibb.co/Yf5FL8Z/hubs-1.jpg
https://i.ibb.co/SrLtjKC/drive-hub-redesign.jpg
https://i.ibb.co/kxhpd3V/hubs-5.jpg
https://i.ibb.co/YpxTfhS/hubs-6.jpg
https://i.ibb.co/0fgqQZg/hubs-2.jpg
https://i.ibb.co/VTmHSnR/hubs-3.jpg
https://i.ibb.co/8N16GCZ/hubs-4.jpg

https://i.ibb.co/Ltrtf1q/Cylinders-2.jpg
https://i.ibb.co/5BV3jqN/Pump-compar...s-Leimbach.jpg
Magom cylinders + Pump arrived. My previous pump is just worn out. New pump (upper) is a totally different design and not well suited to swapping the motor. Motor shaft has a detent pressed in to drive the pump pinion. Low parts count, but too much effort for me to mess with. May revisit Leimbach pumps or maybe a premium Kampshoff. The Leimbach motor attachment is pretty slick as shown. Would be easy to cut down their mounting adapter or make a fresh one to minimize OAL.

Focus is getting the 4WD and steering connected up. That will remain no matter what the hydraulic end up morphing into. I have to re-cut all the axle motor couplers since the new CVD are 2.5mm instead of 3mm like the previous.

Re: TH407C Telehandler 1:14 scale
 

Looking good, I like the axles. What kind of plastic are you printing those parts from? Nice thing about these machines is that you don't have to make some kind of suspension system for them.

Re: TH407C Telehandler 1:14 scale
 

The white parts are SLA Accura 25. Supposed to be similar to an injection molded polypropylene. The grey parts are also SLA but Accura Xtreme Grey which is similar to an injected molded ABS. Both are from Xometry.com

I'm happy to avoid any such suspension. Much simpler this way with just a pendulum rear.

Re: TH407C Telehandler 1:14 scale
 

Ah, that makes sense. Looking at your parts they looked to be too smooth and shiny for fdm unless you post-processed the heck out of them and I couldn't see resin parts being strong enough for that application. Hadn't heard of those materials before but will keep them in mind for the future. How is Xometry to work with? I used Shapeways a few times until they went under. Supposed to be making a come back but we'll see.

Re: TH407C Telehandler 1:14 scale
 

Blender:

Any chance you could give us family picture, as an exploded view, of the parts in that axle? I currently don't have any plans for a 6x6 version of my Frankendiff axle, but... I'm not above "borrowing" a good idea when one comes along. Your use of that Losi axle as a starting point certainly qualifies it as a good idea.

Ya know.... I never REALLY was happy with my N20 gearbox solution for the axles when I was working on my Bruder Manitou conversion. Maybe I need to pull that guy out of the box where it's been "resting" for a while, and take a fresh look at it.

Don

Re: TH407C Telehandler 1:14 scale
 

Modern Resin parts are not too bad. They make a chalky dust when drilled/ filed. Some print vendors only offer generic version of the above material. I can't really tell a difference in practical use.

I was also a die hard Shapeways user. Their stainless steel sintered bronze and lost wax cast brass parts were amazing. I used the brass to fix the hinge on my ZX245 with great results. I was sad to see them go, but was disappointed how they handled the bankruptcy. That is what brought me to Xometry. They have similar capabilities in terms of printing and their machined parts now use the same quoting template. Printed part cost is similar to shapeways, but lead time is faster at Xometry.

Used to use Hubs.com for machine parts for my full size 4x4. They got bought by protolabs and are not as well priced anymore. I still have them quote stuff once in a while

I also use Autotiv to print parts. Their pricing is hit or miss. Sometimes very affordable, other times it's a go-away price. They make nice pieces and are responsive via email. Their machined part lead times are long. They are East coast based which isn't great for me.

Machined parts at Xometry are made overseas, but have a 7 day lead time. Add ~3 days for international shipping (included). Not bad.

I've driven it around in a past incarnation. It's workable. Not really a machine that will travel across a large course. That's what trailers are for. In tight spaces unloading jersey barriers I think it will be OK. Won't be able to dig or load a dump truck. The Lesu MCL8 is only slightly better in term of drivetrain. No room in there to swap parts out, so it stays stock.

https://i.ibb.co/rdJrFFp/Axle-Exploded-View.jpg

I didn't include the hardware, drive pins, etc since I didn't model it. I'm not making a production-quality drawing package here. Originally i was reusing the Losi MRC steering knuckles. They have a different drive pin location than the MiniT CVD stubs. That's why the picture a few posts up shows the grey printed steering knuckles are deeper. Also lets the bearing space out a bit.

Re: TH407C Telehandler 1:14 scale
 

while i'm here I did rough in the front steering. Not really fan of how it looks. Works OK, but the M2 rod ends are very sloppy.
https://i.ibb.co/X7yhGDh/steering-linkages.jpg

This got me thinking.... can i make the steering more scale. Full size machine uses full hydro steering. I won't like the way that drives, so I need to keep servos. Looking at swapping in rack and pinion steering to kind of mimic full hydro look. Rack gears can be bought at SDP-SI. Their metric flavors are lacking, but English size is OK. Might as well build a scale inner tie rod to omit the sloppy rod end. Had to test this part out to verify I can do it. Pinion will mount to a servo horn and be cut down to a sector gear.

https://i.ibb.co/hB2LLXV/steering-rack-and-pinion.jpg
https://i.ibb.co/sjzs99H/Steering-ra...5-dia-rack.jpg
https://i.ibb.co/M7Ln2TC/inner-tie-r...of-concept.jpg

3mm ball bearing drilled/reamed to 1.5mm at ~2.2mm depth in the lathe. Welded to a stub of stainless rod. Sits in a socket cut using a 3mm ball ended endmill. Makes a nice fit. Rack is 0.25in diameter. The have smaller diameter, but it doesn't play nice with the 3mm ball size. I'm not sure i can go any smaller than 3mm. Rear will be improved a lot with this. Less bump steer and easier to assemble.

Will need a chassis rebuild to fit. Need to recut the chassis to get the Leimbach pump bolted down anyway. Will make a couple other tweaks at the same time. Nothing like almost starting over :o

Re: TH407C Telehandler 1:14 scale
 

Thanks for the exploded view. One more question. What's the OD of the Losi axle stub that goes into the coupling which connects it to the N20 gearbox?

Thanks,
Don

Re: TH407C Telehandler 1:14 scale
 

The MIP CVD losi axle where it goes into the coupler is 2.40-2.62mm diameter. It's a bit smaller near each end and largest at the center. Must have deflected while MIP machined it. 2.5mm nominal. That's the bummer since i made my couplers 3mm to fit the MRC parts

For comparison the losi LMT18 axle is less consistent diameter in the same region which was my main reasoning for not using them despite being less expensive.

Re: TH407C Telehandler 1:14 scale
 

Thanks Blender, you've given me an idea for modifying the axles in my Frankendiff. Now that I've got the remote readouts installed on my Sherline I can get back to working on the diff.

I will still need to shorten each axle by about 30-ish mm, but my new idea cuts the required machining steps in half.

Plus, thanks to your input, I've now got a handle on making a powered front axle.

Re: TH407C Telehandler 1:14 scale
 

Shapeways is apparently back in business with a couple of it's original investors now back and running the show. Their web site is back up and running. They seem to have everything except the store where you could buy designs. All that data was apparently destroyed/lost in the bankruptcy. They did buy up another site similar to thingiverse and pritables called Thangs.com though.

Re: TH407C Telehandler 1:14 scale
 

Blender:

FYI - I got some of the front axles for the WLtoys 12428 1/10 scale 4WD crawler. I wanted to see what they looked like, and also to determine if using them would make it possible to build a powered front axle. They have a slight taper from the inboard end at about 2.5mm to about 3.1mm at the outboard end next to the joint. (They look very similar to the Losi axle.)

Now that I finally figured out the secret to getting the screw loose that was holding the gear on the donor rear axle shaft, 10 minutes in a 300 degree F oven, making a powered front axle is very do-able. It will require some minor redesign of the axle housing, but that will just keep me off the streets and out of trouble a little longer.

Re: TH407C Telehandler 1:14 scale
 

Blender:

Got a couple of questions for you. What are you using for the steering knuckle pivots on your axles? It looks like a socket head cap screw of some sort? Do those pivots just thread into the resin housings, or do you have some type of insert in there?

Don

Re: TH407C Telehandler 1:14 scale
 

FANTASTIC build!

Re: TH407C Telehandler 1:14 scale
 

Stock losi mini rock crawler hardware is a flanged metal bushing and a unique socket head cap screw with M2 threads, but a 3mm diameter shank. The screw cinches the flanged bushing to the housing and the knuckle swings on the bushing. Bolt does these into the housing. No insert. Works fine, but I can't get replacement parts anymore. Grabbed some bronze rod to turn some spares, but haven't started.

Anything that keeps us out of trouble is time well spent.

https://i.ibb.co/HTGDp6nd/steering-close-up.jpg
Can kind of see the bushing under the screw head and the flange near the axle housing.

Thanks skeeter. I've been slacking the last few weeks, but I am still going, at a slow pace.


Got the gears on the servo horns. Took a few tries to drill/tap the first one :o
https://i.ibb.co/qLQJMg18/steering-parts.jpg

The 2mm stainless steel tie rods are a bit too hard to thread. Thought I bought annealed, but maybe not. I need to remake the batch in 2mm carbon steel since I have some on hand.

Also cut down the leimbach motor mount. I like their design, but it wastes a long of length. I think I cut 6mm from it. Now it's limited only by a different shaft coupler inside.

https://i.ibb.co/ccvPtcjv/hydraulic-...pler-short.jpg

Re: TH407C Telehandler 1:14 scale
 

Blender:

Thanks, I was thinking about using a small shoulder screw for the pivot. They are available in thread sizes down to M2, usually made of 304 stainless. The M2 shoulder screws have a 2.5mm OD shoulder, and the M2.5's have a 3.0mm shoulder OD.

Re: TH407C Telehandler 1:14 scale
 

That's some a long way since I saw it last. Good to see your making some pretty good headway on this little unit.

Re: TH407C Telehandler 1:14 scale
 

Thanks! I've lost a little of my momentum, but I am making progress still.

Latest task was redesigning the chassis to fit the rack and pinion steering. While I was in there I made room for a leimbach pump/custom reservoir and upsized the lift cylinder from 10mm to 13mm to account for the possible lower pressure. Boom had to be rebuild to change one part that I can't easily cut out for the bigger cylinder.

I also made a little tweak to fit lesu MCL8/skidsteer implements. Forks are my only plan, but technically I could attach anything. No aux hydraulics so the fun will be limited. I may try to get some wires routed to run electric accessories.

Axles, body, cab will all bolt on with no changes. Despite how it looks it closer than ever to running. Front steering works great. Rear needs a little tweaking, but nothing major.

https://i.ibb.co/RTnv7wcg/chassis-re...steering-1.jpg
https://i.ibb.co/d811HTj/chassis-rebuild-steering-2.jpg
https://i.ibb.co/3Lfkb51/steering-1.gif
https://i.ibb.co/jmzsYpm/steering-2.gif

Re: TH407C Telehandler 1:14 scale
 

That is really looking good. Love the rack and pinion steering setup. Can't tell for sure from the short videos, you have limit switches on the pinion drive motor to protect it? Odd looking plate on front of pinion gear.

Re: TH407C Telehandler 1:14 scale
 

Thanks Zabco

Pinion is actually driven by a servo so it has all the built in limits and self centering. Front of it is an aluminum servo horn. OD was cut down a little and there are a few extra holes in the face from me measuring wrong repeatedly :o

Re: TH407C Telehandler 1:14 scale
 

Blender:

The extra holes are un-documented features. If Microsoft can get away with it so can we.

Don

Re: TH407C Telehandler 1:14 scale
 

Ok, now I fully understand what you've done. Great idea to save for future reference.

Re: TH407C Telehandler 1:14 scale
 

Sorted out the binding at the rear servo and that tightened up some of the freeplay in the splines. Assembled the steering to try it out. Rear knuckles need higher mounting point to prevent binding when acticulated. Easy fix. Inner tie rods will need threadlock for final assembly.

Ackerman geometry was only mediocre in CAD, but looks to function pretty well. Neither tire scrubs when rolling through a turn. I like it. 2S lipo on the drive is justright speed wise. Good control. Slow if running on the "road" with trucks.

https://i.ibb.co/B5zDd4zv/milling-servo-horn.jpg

https://i.ibb.co/Gf3h4RFP/steer-test.gif

https://i.ibb.co/JRjbZKVR/drive-test.gif

Couplers on the axle shaft are a press fit, but do spin under high torque. Pinned one pair with a 1mm stainless steel rod. Buggered up the ends with the welder to retain them. Need to do the other pair.

Also got my sherline mill out of storage and freshened up. Nice to have a capability again. Been eyeing DRO systems after reading ddmckee's conversion.

Re: TH407C Telehandler 1:14 scale
 

Also removed the counterbore of another Leimbach valve set. These are the mini sized. Way smaller, but not enough to fit a 4th spool. The factory counterbore at the pump and tank connection don't work with my SMC 90 deg fittings, so I machined a little pocket.

https://i.ibb.co/KxP3335v/valves-mini.jpg

Will use the stock pump tank for first run, but will try to build my own out of welded stainless. If that leaks I'll have the tank printed as MJF nylon.

Boom is coming along tacked together, but need to turn some spacers to (re)build the tilt mechanism.

Re: TH407C Telehandler 1:14 scale
 

Since you have a gearmotor for each wheel are you doing any mixing to get some differential action?