Taking Inventory

[Heavy Metal]

I'm resuming a project I put on hold 2 1/2 years ago. At the time I had accumulated most of the major components for the build. I'll start a build thread once I have a frame and four wheels. Wasn't sure where to put this post - I've had a post moved once already!

Here's what I am aspiring to build...a 1:14 scale JD 710J hoe loader:


The 1:12 Ertl in the pics below is not the project...that was just a means to experiment and learn how to assemble a working miniature hydraulic system. It has seen about 20 hours of run time over the last couple years with no maintenance required. The clippard cylinders haven't leaked a drop and everything runs perfect when I dust it off and fire it up. Here's a link to a quick test run back in May 2008.
http://www.youtube.com/watch?v=EZ4FLg9d6R4

Here is the Ertl test rig and everything I had stored in a bin in the garage. Leimbach hydraulic pump and spool valve with assorted fittings, Clippard cylinders, hose, fittings and clevis attachments, a 5-ch radio and reciever from an E-Flite helicopter and a pair of motors from Anaheim Automation. Also still have my notes, calculations and field measurements as well as the scale drawings I did to see if the pump and spool would fit. Sadly I cannot locate the files of the photos I took when I did the field measurements...might have to find a 710 and do another field trip.





Big ticket components I still need are:
8-ch radio and receiver
Leimbach 6 and 6 channel splitter
ESC
Wheels and tires
Everything else will be fabricated or take offs.

Even though I have all these parts already I feel like I'm stuck until I settle on the axle, wheels and tires. I'd like to hear some opinions on this and the motors but will start a different thread for those questions so they are aptly titled.

Joe

[Espeefan]

Hi Joe, I remember when you posted this project on Scale 4x4. I wouldn't be surprised if this thread gets moved the construction equipment section. You've got a really neat project going there and I'm looking forward to seeing it get back on the main burner. Really curious to see how you will fit everything inside the model to make it functional. I think you've got a lot of work ahead of you!

I think your best bet for the axles would be to pick up some gearhead motors, and then your hubs and wheels could bolt right to the output shaft. No other transmission would be necessary. You would only have to make an axle of some kind, or an axle tube, and mount the gearmotors inside that, or to it. If you are going for a 4wd front axle, then maybe you'd be better off with a single gearmotor and a transfer case with a center differential of some kind, which would allow for a speed difference because of the different sized tires front to rear. The more components you add, the less room you'll have inside for all the other important mechanics and electronics, so maybe it would be better to have the model be 2wd. A powered front axle would be real challenge, although in 1/12 scale, you might just be okay. There are a lot of 1/10 scale axles out there for trucks that would probably be a good fit. Tamiya's TLT-1 axle, Losi's 1/16 scale crawler axle, or in metal, RC Channel has a couple different axles with steering knuckles too. One is narrower and one is the same as the TLT-1 axle. Or head over to RC4WD's website and check out all the different axles they offer. I think you would easily find something that would be perfect. Another option, and I'm just brain storming here, would be to use the gearhead motor idea in the rear of the model, add a third gearhead motor for driving the front axle of your choice, and do the math so the ratios come out close. You might need something like a 20:1 gearhead motor on the front axle and a 40:1 set of gear motors for the rear axle, if the tires are twice the size. The front axle could always be engaged, or maybe disengaged electrically, but I'm not sure the front tires would free wheel, as it's not easy to backdrive a gearhead motor. It would better to have a shaft coupling that sides over a splined shaft to engage the front axle. I think it's kind of a horse a piece. With gearhead motors you'd have no transmission taking up valuable space inside the model, but then you'd need two or three motors. With a single motor, transmission, and transfer case, you add a lot of components. Perhaps a single gearhead motor in the center of the model, powering a transfer case, the rear axle, and a reduction box for the front axle would be in order?

[Heavy Metal]

More on my JD 710J project (is it really a project yet?). This is the part that really has me stuck. I think once I solve this I can get this project moving. I really want tires and wheels of correct scale height, width, rim size and tread pattern and made of nice soft grippy rubber.

I have accumulated maybe a dozen different tires and wheels from die cast, RC monster trucks and crawlers, etc. for this project and nothing is quite right. Either the rubber is hard like plastic or one of the measurements were not quite right (like, diameter perfect but way too wide).

At this point I'm not worried so much about the wheels - if push comes to shove I can turn these myself on my old 7x10 mini lathe or I believe there are one or two on this forum that might be interested in doing on a fee basis. It seems to me the tricky part is the tires. In my files from a couple years ago when I started this I found correpondence back and forth with a German manufacturer who would create rubber tires for RC trucks and tractors to custom spec. That company actually referred me back to PMD for order placement from the U.S. but I never followed through because the costs for two different custom sized tires would have been $500 or $600 total (additional tires were $20 each). This RC model is going to have cost a couple thousand or more upon completion so I'm not opposed to going this route if I have to (assuming it is still and option) but saving $600 would certainly be nice.

Here are the scale specs for the front and rear wheels and tires I am trying to locate:
Front:
Tire Outside Diameter: 2.71"" (69mm)
Tire Width: 1.07" (27mm)
Rim Diameter: 1.43" (36mm)
Rear:
Tire Outside Diameter: 4.14"" (105mm)
Tire Width: 1.5" (38mm)
Rim Diameter: 2" (51mm)

Any suggestions to help me find these would be greatly appreciated. I would be happy with +/- 1/4" (6mm) on any of these measurements. Posting the JD 710J picture yet again to show tread pattern and rim style I'm looking for.



Regards,

Joe.

[Espeefan]

Joe, I can't offer to much advice on tires. That will probably be the hardest part of building this model. I will mention, however, that a lot of the guys into rock crawling have sucessfully narrowed up tires for better performance. This might be something to consider, as Tamiya makes the V-treaded ag type tires for their monster trucks. The Clodbuster and TXT-1. I have seen guys cut these tires in half and narrow them up. They basically glue the tire back together and re-enforce the seam from the inside with a thin piece of rubber, like bicycle inner tube. It works very well, but I am not sure what the diameter is of the Clodbuster tires, right off hand. The same guys also narrow the plastic rims, just as easily, so that could be a very affordable option for rims as well. I know the tread doesn't quite match the industerial v-tread you would need, but it's a good stand in. Front tires might be a little harder, but there options out there as well. HPI makes the Wheelie King monster truck, and it uses smaller v-treaded tires, similar to the Tamiya ones. Pro-Line used to make a tire called the Masher and it's about as nice of a tire as you can find for tractors or construction equipment. They aren't available anymore, so it might be a challenge to find them. Not sure on the tire's over all diameter, but the inside rim is 2.2". There are many other 2.2 and 1.9 sized tire options to consider as well. Not many with v-treads, but if you are okay with a 2wd front tire you might be able to find something.

[Heavy Metal]

Thanks Espeefan. This helps a lot. I have four really nice tires...probably Clodbuster...that are perfect diameter outside and inside and nice rubber but are almost an inch too wide. And now that you mention it I do remember reading about guys cutting these down. Maybe I will give this a try. Do you remember if the tires manufactured in this way held up to real use? Like, if they were part of the Lil Giants construction fleet...would they last any length of time?

Any idea what technique is used to cut these cleanly and accurately? Maybe I can rig up a way to mount them to my lathe and use a razor...hmmm....

[Heavy Metal]

Espeefan: This will be 2WD so don't need to worry about driving front. I don't think it's possible (without extreme machining and expense) to make this 4WD.

I had same thought as you on gearhead motor (mount rear wheels directly to motor shaft) but I guess I miscalculated and the motors I bought are too long to mount back to back (see my other thread). Do you have a suggestion on where I might find suitable gearhead motors that have shorter overall body length (1 3/4" or less) and between 150:1 and 200:1 ratio? And still have good power for this?

And yes, I have heard a few times that 1:14 is too small...or at least an extreme challenge. But I have drawn it up and on paper and it seems to fit so forging ahead. The battery will have to go inside the cab.

[Hos1880]

search for Dakotah toys in Madison SD not sure if they still have there website but will try to find a phone number for you. they specialize in toy farm equipment and parts. (605) 256-6676 i do believe is there number they have a ton of 1/16th scale parts

merritt

[Espeefan]

Joe, perhaps another option would be to get yourself a regular truck axle, and get a new gearhead motor that could couple directly to the input shaft of the axle. If you bolted it right up to the axle and coupled the output shaft of the gearmotor to the input shaft of the axle, maybe that would work okay. The axle could be rotated or clocked straight up, and the motor could be standing on top of the axle, or layed the axle down flat and the motor could sit in the belly of the model. Just another idea!

[Heavy Metal]

Espeefan, excellent idea and actually drew it up that way at one time but had problems with the fit. Still a possibility. What is most common rear axle set to find and use? Tamiya 1:14 truck or something else? I think I read these are 3:1...is that correct?

[Heavy Metal]

Thanks Merritt. Will definitely give that a try on Monday.

[mtdriver]

As long as you have a tight seam and use good tire glue (I like Team Losi red) they will hold together even without reinforcement. I narrowed and reduced the diameter on some Proline Hammers and they held up to a Traxxas brushless on 3 cell lipo in one of my mud trucks. Was good for 40 mph easy.

[tracksntreadslou]

Hey Joe check the tire tread pattern on these tires ...Not sure about the diamater

[Espeefan]

Ahh, I forgot all about the Tamiya Blackfoot tires! Those might be perfect for the front tires, as I believe they are smaller then Clodbuster tires. Also consider Tamiya TLT-1 or Wild Willy V-treaded tires. They are about the same size as the Blackfoot tires, but standard V-treaded, like the Clod's. While I'm thinking about it, another company named Imex made a Clod tire that is more industerial treaded. Road Hawgs, I believe is the name. Sometimes called Imex Pullers. They are slightly smaller in diameter then the Tamiya chevron tires, but very close, with the proper tread, if not a bit wide spaced.



Also look at this page. The jumbo kongs could work for rear tires, and the chevron standard size for the fronts, maybe? http://www.imexrc.com/servlet/the-Ti...res/Categories

[Espeefan]

A Tamiya semi axle would be a great axle to go with. It's narrow enough for what you need, maybe a little more narrow then needed, but you could always make your wheel hubs a little wider to compensate. I'm not sure what the differential's ratio is. Been a long time since I had a set of these axles laying around. They have the same diff ratio as TLT-1 axles and use many of the same parts.

There are a lot of popular axles out there you could look at. Axial's SCX10 axles, or maybe their AX10 axles. Might be the same basic design even. Possibily you could consider Axial's XR10 axles too, but those are a motor on axle design, similar to what the Clodbuster uses, but narrower. These might be a little on the wide side, and the differential is non-existant. They have a spool so both tires turn together, regardless of traction. Otherwise, you could also browse RC4WD's axle section. They have a lot to choose from also. Take a peak - http://store.rc4wd.com/Scale-Crawler-Axle_c_12.html

I think bang for the buck, you'd be best with the Tamiya axles. And we know they are strong and very common, so getting them and parts would be easy.

Another crazy idea might be a gearhead motor that has a 90 degree bevel drive box on it. Two of those could probably fit in the rear of the model, although the motors would be intruding on some of the space in the belly area of the frame.

[Stepside]

I am so glad to see this one back up! I remember going back through pages on the Garden to find the build. Looking forward to some more progress!!!

I'm tuned in!

[Blender]

This is going to be an earth shattering project. It's one of those things everyone wants to build, but no one actually does. Any plans to deal with the high number of hydraulic lines in such a small space? I found they were larger in diameter and stiffer than expected.

How was Anaheim Automation to buy from? The lack of online store scared me off.

[ihbuilder]

Joe , I've been planning on building a cat 416 (the early 1's ) I would stick with the gear motors . Your going to need all the room you can get . check the gear motors on robot market place . I'll be watchin this 1

IHSteve

[Lil Giants]

If memory serves me correctly, the tam axle ratio is 2.73.

Have you considered the difference in using Leimbach's minature hydraulic system for space issues?







B - 44mm
H - 9mm
H (with servo added) - 37mm
T - 18mm


...we'll claim your thread to the construction equip forum to give your unique & original build a permanent home.

[Heavy Metal]

Lou: Blackfoot tread pattern right on the money but looks like these are 130mm so too big. Thanks though.

Espeefan: Thanks for link to Imex. Had not run across this yet. 1.9 series has right outside diameter but no chevron patterns! RC4WD axle sets are nice! Wow.

Originally Posted by Blender

This is going to be an earth shattering project. It's one of those things everyone wants to build, but no one actually does. Any plans to deal with the high number of hydraulic lines in such a small space? I found they were larger in diameter and stiffer than expected.

How was Anaheim Automation to buy from? The lack of online store scared me off.

Gee thanks Blender. No pressure. I hear you on the hydraulic lines...it will be a challenge. I'm using the smallest available clippard hose (1/8" O.D., 1/16" I.D.) on the Ertl test board and I was happy with the flexibility of these lines and the flow rate seemed okay. You have to really force them onto the smaller metric Leimbach nipples (2mm I think?) on the spool valve but they have been in place for 2 1/2 years without splitting and seem to work fine. So yes, I've considered the lines in all my measurements but haven't drawn detailed plans of the routing...sometimes you just have to size it up and say "I can make this work". Anaheim Automation was great....just had to call them up. They said they get quite a few orders from hobbiest.

Originally Posted by Lil Giants

Have you considered the difference in using Leimbach's minature hydraulic system for space issues?

You know I remember seeing these on the Leimbach website and I don't know why I didn't go this route. Probably because I was dealing w/ Ric at PMD and was getting in a hurry and just buying what he had in stock....seems funny being 2 1/2 years later and all.

I'm going to try and work with what I've got. Nice to know this option is in my back pocket (no pun intended $$ ha ha).

Joe

[Espeefan]

Originally Posted by Lil Giants

If memory serves me correctly, the tam axle ratio is 2.73.

Have you considered the difference in using Leimbach's minature hydraulic system for space issues?







B - 44mm
H - 9mm
H (with servo added) - 37mm
T - 18mm


...we'll claim your thread to the construction equip forum to give your unique & original build a permanent home.

Hmm, I've never seen that before, Joe! I could think of a couple uses for something that size. Any idea how much fluid that unit holds? Enough for a 4 or 5 stage dump box cylinder?