Grastens

Some time ago, I began the search for a comm lathe. It started with the revelation that I am neither possessing a brushless RC car setup nor close to owning one. I suppose I also found the brushed motor to hold more aesthetic appeal than their brushless counterparts, perhaps in the same way that some automotive enthusiasts prefer the appearance of carburetors under the hood to fuel-injector bodies... Whatever the case, I had a surfeit of brushed motors, and no way to satisfactorily service their commutators. With a comm lathe, I would not only secure my commitment to brushed motors, but also get more use out of those which I had. It should be noted that while I am not a millwright or machinist, I do have some experience with similarly-tedious tasks; I used to sharpen ice skates at the local sporting good store by hand. Getting the correct radius on a skate blade using a manually-adjustable holder and a grinding wheel took some practice and skill, as the shop could not sharpen every skate on its automatic machine (figure skates and ice hockey goalie skates were almost always hand-sharpened). I guess I came to embrace this skill, because the prospect of truing commutators no longer scared me after that! Several months later, I snapped up a used Hudy comm lathe for a discounted price (yet still over what I should have paid, but I can't argue now ). It arrived a few weeks later: This thread exists at the request of a few members on TamiyaClub who were well aware of my struggles to locate a comm lathe. Some were curious as to how one operates and functions, and so this will document my findings and thoughts. Initially, I had read that my Tenergy TB6B charger, in addition to charging batteries, could serve as a DC power source. With that in mind, I attempted to replace the alligator clips on the comm lathe with a Tamiya battery connector, as that was what I had at the time. What you see in the above photo is my second attempt, with the first one already removed from the cable I could not figure out if the Tenergy TB6B actually has that particular function (my investigation says no), so instead I soldered a male Tamiya connector onto the end so I could use a standard Ni-MH battery (which I also use to this day). While I do not like the resulting lack of a speed controller, at least I have a ready and simple source of power. For the uninitiated: a comm lathe uses another 540 motor and a high-tension rubber belt/band to spin a motor commutator, with little to no axial or lateral play. As a result, a fine blade can be used to "true" the commutator while it is spinning in this fashion. The blade is manipulated by two fine-adjustment dials which control axial and lateral location of the blade relative to the commutator, allowing precise passes of the blade against the comm. In this way, material can be removed from the comm, and a uniform finish can be achieved. The resulting clean comm surface gives the effect of a near-brand-new motor once reinstalled. Some adjustment was required to ensure I would not overshoot the commutator or else travel too far past or into it. Hudy comm lathes use standard hex screws to secure things; I was able to use a standard Tamiya mid-size hex driver from my RC Craft Tool Kit to tighten everything down: My research found that many who did/still true their own commutators preferred the hardened V-guides to the ball-bearing guides pictured on my comm lathe. I preferred the ball-bearing guides since I trusted bearings more than hardened guides for long-term use, although I have since found that replacing individual ball bearings in the guides is so tedious as to make purchasing new guides the better option. I do know a vendor who still sells those parts, so if I ever use this comm lathe to the point where the guides start wearing out, I can always either switch to the hardened type or stick with the ball-bearing units. After checking that my soldering work on the battery connector was in fact functional, and testing a 7.2 V battery successfully (I now understand why high-turn motors are required on comm lathes!), it was time to see if I could truly true!

... Wait, who's updating this thread?! Oh, right The first step: The cast-metal gearbox, with its solid final gear and mixture of plastic and metal, is the first item to be assembled. Memories of my first Buggy Champ had me recalling filling this up with molybdenum grease, being persuaded by my local hobby shop that it was "the same, if not better." Ah, youth! Metal-on-metal contact still benefits from the black grease, but the intervening years have since allowed me to choose the kit-supplied ceramic grease for this car. The gears in question: I might have run into that brass idler gear during my (mis)adventures with the vintage Audi Quattro... In any case, smooth-rolling ball bearings are a welcome improvement over metal bushings. Everything went together nicely: And the intervening years has also taught me that a thin coat of grease works just fine! A small collection of cap-head screws seals it up: Wherever my old Buggy Champ went off to, I am sure the new owner would be having quite a time prying loose the seized screws on its gearbox! I am not entirely looking forward to this development on my new buggy, though I won't have to worry about that for a while! The packaging of the parts is something else: To get through the first two steps, I needed to open almost all of the metal parts bags! They were all open before the build was halfway through. Such chaotic packaging might make sourcing spares a bit of an expensive proposition, although at least they are still available! With the universal joints added, the rear torsion bar linkages are next: I am surprised how effective this system is, though less surprised that it may not perform as efficiently as today's designs. It does speak to Tamiya's attention to full-scale detail that this was the solution envisaged for this chassis; as before, the actual Volkswagen Beetles in period used a similar configuration. It translates well to scale performance as well as authenticity, which is probably why racers were left wanting once newer designs came out... Rear arms and the motor are added: The first time around, I had tremendous difficulty with these steps. Since then, my dexterity has improved, and I am happy to report that this part of the build was fairly easy I can still hardly believe that the motor is not bolted onto the gearbox, though For the uninitiated (and it may be apparent in the shot of the manual visible in the above photo), the motor sits in notches cast in the right gearbox half, and is held in place by the clear motor cover on the left half. Using the larger pinion may also prevent the motor from backing out. It does give an appreciation for the fit of the parts, since generous tolerances in this area would definitely lead to premature drivetrain wear. The spur gear lives under a similar-style clear cover on the right side of the gearbox: To think I once used molybdenum grease here, too! I have come a long way since those (expensive) early days. These pieces: Secure the rear cage to the rollover bar: I did not realize that the rear dampers also fasten to the screws running through the pipe clamp halves. The plastic cage helps with the rear-end impacts; a metal part would stress the gearbox more under compression (and yet, I still ordered a metal front bumper!). And while I am not using a period receiver (and therefore do not require the rear aerial location), I decided to use the metal aerial mast anyway, for visual effect. It is my understanding that the full-scale racers used masts of their own for identification and visibility among the steep sand dunes - useful on an event like the Mint 400... Joining the torsion bars with a brass sleeve, the nature of the undampened rear suspension is quite evident: My scant background in materials engineering has me dubious of the reliability of torsion bars, but then, that's why it is only a scant background! For this RC car, I am sure it suffices - and replacements are easy to source/fashion, regardless. And with that concluding the rear gearbox, it can be attached to the chassis plate: I am glad I invested in an alloy chassis; I found the suspension to be much less effective with the more flexible stock FRP option. Front suspension and dampers are next! Are the latter as leak-prone as I remembered? Likely!

Presenting: Inspired by both Gran Turismo's Grand Valley Speedway and Autumn Ring, this circuit uses a slightly larger format to add some higher-speed sections. Mixing technical corners with slightly-longer straights, hopefully this track will allow some of the faster cars to approach their top end - although that first corner might have something to say about that Pending approval from @TurnipJF, we have Round 24! Good luck, everybody!

On it! Will have it ready soon Update: it will be posted here by June 6, EST!

I think they are close enough to the Tamiya Striker that even the purest of purists wouldn't mind I sure don't! I love my Striker, and find the FX10s to be quite neat. Besides, with a good-looking collection of them, you won't have a thing to worry about!

Interesting! And this really makes @nicksincrc's lap totals even more impressive - I do not intend to be patronizing, but I would being unable to use fine motor skills to drive these things is definitely an obstacle. Nicely done, sir I tried scaling up the track for my first entry in Round 17 - the mini Watkins Glen circuit. It was actually quite fun and more like driving the actual course, although the space required to do so was definitely generous! Think I will be dusting off my TamTech 1:24s

Magnificent track and artwork, @Ferruz! This should be a fun one *dials in 20 degrees of toe-out*

But the joke's on them, because now I am inspired

@Ferruz it would be my pleasure However, I look forward to seeing your circuit plan!

Aces! You did justice to a most-unusual subject. Great to see this mad GT1 racer done to such a high standard in scale

Hats off to you, KEV! Fine work on that cap! This is a fun build to follow

Whenever I was off Tamiya, I was onto Lego It seems this is a phenomenon!

A very inspiring build! Excellent work

The 19T pinion should work. I cooked a 13T brushed motor on a TA-02 on that amount, but a 20T brushed motor holds up nicely with a 21T pinion. There is some sort of conversion at work to determine the output of a brushless v. brushed motor for a given turn rating; it seems a 13.5T brushless motor may be equivalent to a 17T or so brushed motor. If that is correct, then your pinion should work for the 037! If not, there may be room for a motor fan, even with the cockpit set equipped...

Lovely presentation It looks great! I can hardly wait for 2 and 3

Bits and bobs do figure into my 037's engine bay, too, so be sure to keep that in your figurative back pocket Incidentally, a 3D-printed version of the Toyota 4A-GE for use in those engine bays is also available. I have one set aside for my next(!) 037, with the advantages being crisper detailing and ease of modification (i.e. I can sand off the valve cover text instead of covering it with half-effective tape ). I used the polycarbonate bay for the first one since I did not know that other option existed; hence, with the 3D-printed Toyota, you can have the best (or worst!) of all worlds! But, as bits and bobs go, the engine bay only looked partly-convincing on my 037 because I surrounded it with scratchbuilt pieces. For inspiration: a tube of 1150 plastic bearings became a supercharger body; and leftover kit sprues became a roll cage and inlet ducting, and so on... I look forward to seeing your work!

Denys Cherepinskyi is a dear friend of mine who, due to circumstances beyond his control, is fighting for his life in Ukraine There is little I can do for him, but should the unthinkable happen, at least there will be this little corner of the Internet where his name lives on... I also know he found RC cars interesting - I recall him asking questions about mine whenever I brought them in to bash around on break - so this is a bit of a tribute to him. Here's hoping we see him again! Anyway, I had no name for this circuit design, so the name also added some class, like Circuit Gilles Villeneuve. Apologies for the sombre tone of the explanation! I still have a feeling to be optimistic somehow.

That is correct. It was easy enough to do with a craft saw; the same hacksaw I used for the heat sink was a bit inconsistent with the rear bumper. From there, mud flaps are almost mandatory

Can confirm; I run mine with a brushed 20T motor, and it has a decent bit of pace... ... aided by this High-Speed Gear Set! I am presently using a 21T pinion with it, and the chassis has proven to handle quite nicely, even built stock. I used one to finish second at Round 19 of the Racing by Post challenge on TamiyaClub - not really a formal racing event, but still a result I am proud of, for what is essentially a rally car running on pavement! As for the rest of the build: There always seems to be issues with the front wheels rubbing on the body arches at full lock. On mine, I found I needed to remove about 2 mm of plastic from the front of the arch to clear the stock tires: Of course, you may need to remove even more if you run larger tires, i.e. rally block treads or the aftermarket Pirelli rally tires available online. Under extensive running, I have also found that the step screws holding the left rear upper suspension arm to the hub (and occasionally, the one holding the left rear damper to the suspension) have a tendency to loosen up. If unchecked, you may lose a dog-bone drive shaft and a rear differential cup as a result! I switched my 037 to rear universal drive shafts to address at least the former, while stocking up on spare diff cups for the latter (part number 53217, I believe). It appears to be an effect of the 'handedness' of the screws; a similar phenomenon can be observed on the front right corner, although I have had fewer problems with that. The dampers do call for internal spacers to be installed; I left them out of mine and played with spring lengths to facilitate off-road running. At present, my 037 uses the stock springs, but about 8 mm of spacers to take up the residual space on the damper bodies, as well as to add some pre-load. Dust and grit can get into the rear gearbox around the spur gear. I used a piece of tape, and then a thin line of grease around the perimeter of the gearbox, to mitigate the issue. I already had the displeasure of finding a shredded spur gear... I bought a metal motor mount, finding that the stock plastic part tends to flex. Since this adversely affects the gear mesh, a stiffer solution was welcomed. It was also advertised as a heat sink, but I took no chances and fitted a standard external finned sink on the motor. I did have to cut part of the heat sink to fit on the chassis, but the stock Tamiya part I used was easy to manage with a hacksaw. The only other bit of advice I would have is to enjoy it! These cars make fantastic-looking runners, and can play the part, too! P.S.: Should you ever decide to put an engine bay in the back: a lightly-modified Toyota 4A-GE does nicely I chose this for my 037 since there are numerous options available from the RC drift car scene, where that particular engine is a popular accessory. Additionally, it has the right number of cylinders - just be sure to hide the valve cover script if you use one Have fun with the build!

It is looking great so far! As an enthusiastic Lancia 037 owner (the Tamiya version, to be clear!), I am looking forward to seeing this build play out

Presenting: Round 21 will take place at Circuit Denys Cherepinskyi! (pending @TurnipJF approval) This track makes use of a slightly-smaller footprint (7 m x 4 m, compared to the previous 8 m x 5 m), which I hope should facilitate participation. The circuit does feature a crossover element, noted by the directional arrow around Corner Marker 6. Whether or not you make it the site of an overpass, underpass, or jump is at your discretion Though it may be tricky to stick the landing inbounds! Corner Marker 4 is intended as a chicane. It is a simple layout for this round, but hopefully one that is still entertaining!

@Busdriver my build thread may be out of date, but I should still have all my pictures and documentation if you require them for your project! I look forward to seeing it

On it!

Grastens Builds the: A memorable build of great personal significance begins! Overview (aka Grastens' Understanding of the Buggy Champ and its Predecessors) The Tamiya Buggy Champ was released in 2009, as a re-issue of the original Rough Rider that first appeared in 1979. Along with the Sand Scorcher, it played a role in the popularization of off-road RC buggy racing. The chassis featured full cast-metal independent suspension, which emulated the Volkswagen Beetles that was the basis for many dune buggies of the time. As such, the performance was also quite similar to the full-size subject, which at the time represented an improvement over the current state of off-road RC buggies. The Rough Rider in particular was based on the Bob Maynard Racing Funco SSII, and was set to become a properly-licenced version of his bright-orange racer. However, the deal fell through during the prototype stage, and as a result, the name was changed to “Rob Mitchell Racing” (Tamiyabase has some more information on this for further reading). If nothing else, this footnote reaffirms Tamiya’s attention to authenticity in those early days of their RC venture. The suspension was not the only factor influencing its scale performance: the use of a water-resistant mechanism box to protect the electrical components from moisture damage also allowed the buggy to tackle the elements. This opened up new possibilities for running, which contributed to the chassis’ popularity among more casual enthusiasts. The bodywork did require some deviation from the original Funco buggies to fit the mechanism box, but for all intents and purposes the Rough Rider was an authentic dune buggy at 1:10 scale – and a fraction of the price! The combination of scale aesthetics and performance was befitting the “Model Suitable for Radio Control” philosophy that Tamiya’s nascent RC department sought to embrace. With pronounced positive rear camber and no rear differential, the Rough Rider was really best suited for sandy beaches and dunes – again, like the real thing. As mentioned, the chassis was also used for the Sand Scorcher, which took the Beetle theme even further by introducing a modified Volkswagen-style shell over the original platform. Later, Tamiya would use the chassis underneath a Ford F-150 Ranger body as its own release. In response to the growing number of racers using these buggies, Tamiya would eventually develop the chassis further for the Super Champ (now around today as the Fighting Buggy). The chassis became known as the SRB (Special Racing Buggy), and for all its innovation, there were plenty of improvements that could be made to increase its performance. It has been written that the Rough Rider and Sand Scorcher may have created the “cottage industry” of aftermarket parts (think Team CRP, MIP, Thorp, etc.) as enterprising builders and racers sought to gain the edge on the track. Popular upgrades included items such as lightweight suspension arms, alloy chassis plates, parts to replace the mechanism box with a lighter solution (addressed later with the Super Champ), and an ever-increasing variety of wheel and tire combinations. The legacy of the Rough Rider (and Sand Scorcher) may be similar to that of the later Grasshopper and Hornet, which also brought off-road RC cars to a wider audience. As buggy design evolved into something quite different in the name of outright performance, the scale appearance and driving characteristics of the SRBs remain part of a past era, though revived in other genres such as trail driving! Grastens and the Buggy Champ I bought my Buggy Champ at the local hobby shop (back then, Advance Hobbies near Toronto, Ontario) for what was probably $350. I had been in the hobby for about one year, having started with another Tamiya: the Toyota GT-One on the F103RS. I enjoyed it immensely, and a whetted appetite was now eager to try off-road buggies. At the time, I had little clue as to what the Buggy Champ represented. I found myself living the experience of a Rough Rider enthusiast: once marvelling at its performance off-road, I sought to improve its overall handling by introducing new parts. The modifications I remember the most were the alloy chassis plate, the ball differential, and a succession of coil-spring dampers that replaced the leak-prone originals. I had even considered the RC Channel double-wishbone upgrade for the rear suspension, if only because I found the positive rear camber made handling tricky, and the wear on the outsides of the tires was not looking good… Life intervened, as it usually does, and for a period, the Buggy Champ sat along with my other cars on the shelf. Over time, it was joined by others, and as the on-off relationship with the hobby continued, the car saw less and less action – I would be too engrossed with other projects, like the Lancia Rally that I had taken on and with which I began my love affair with RC rally cars. Unfortunately, life then saw me sell the Buggy Champ (along with the shell for said Lancia Rally) when I needed the funds for a trip. I sold the car to another member on TamiyaClub, who, like me, had been looking for a fun and reliable runner. Perhaps it is best that I have since forgotten this member’s name (and I believe this member no longer frequents the forums), for it broke my heart to learn that this member decided it was not to his taste and sat it on the shelf. I had given him a bargain for it, too… It was at that moment that I came to realize my mistake, though it would take some more time to regret it (after all, it was a good trip!). The Intervening Years Over time, while moving a well-loved car for pocket change to someone who did not appreciate it still hurt, I could also understand that the Buggy Champ was a car best suited for a specific set of conditions. As I grew up and settled down, I would continue to waver between full and zero commitment to the hobby. I struggled with unemployment for an embarrassing amount of time, which definitely affected my ability to continue with my RC cars. Even when I did find full-time work, a diagnosis of clinical depression and the resulting medical struggles changed my life and threw it into turmoil… … And as if in the eye of a storm, I calmly picked up my RC cars again. This time, having finally moved in with my partner and being otherwise completely independent, I found I could focus more time, energy, and (most importantly) money on the hobby that I knew I still loved. The acquisition of a Tamiya Hotshot (courtesy of said partner!) rekindled my interest, and a succession of builds signalled my return to radio-controlled cars. And then: well, where I now live, there is a beach less than an hour’s drive away… Could I really be thinking…? Even with all of the other off-road buggies I have now? A Second Chance Everything pointed me towards another Buggy Champ. Remembering how much I have come to miss my first one, I made the decision to find one – and this time, not let go! Unfortunately, like pretty much everything, the Buggy Champs that were once plentiful online and beyond (namely, the ‘Metallic Editions’ in silver and gold) were now going for way more than I recalled. I had to remember that it had been several years since I last seriously sought one out, but this seemed ridiculous; the majority of them were asking $700 and beyond. The advent of coronavirus inspired me to turn ‘local,’ which is to say to the local online classified ads. There, I found a seller who had a new-in-sealed-box Buggy Champ for well under what everyone else wanted for theirs, out of Toronto. It was even somewhat near where I grew up… I wanted it, but my bank account did not! I made a deal to put down a deposit on it, following which I would come up with the rest of the money in two weeks’ time. I had it all paid for by the next week, and while perhaps I could have negotiated a better price, I felt grateful to have found a brand-new one in the country that did not cost me half a month’s pay! The other nice thing about buying within the country is that shipping is commensurately fast. By the following week, I had it in my hands! When I opened it up and set out the shrink-wrapped box, I just stood there, staring at it: while I may never find my original Buggy Champ again, I have been given another chance to experience it. With the experience I had accumulated with other models in that time, I would appreciate it more than I ever could have back then, and now know better than to part with this one – would you believe I embraced the box and told it I would never let go? I was unaware of the full extent of my emotions until the day it arrived. Maybe it will become a nice memory of mine in this hobby. The Kit Many of you have seen a Buggy Champ before, but for the Gamilans, Betelgeusians, generally-uninformed, and nostalgic types like me out there, I have some photos: Would you also believe I found the box smaller than I remembered? The beauty of a new-in-box example is that I can relive the build, too! That blister packaging brought back so many happy memories: Beneath the blister pack with the tires, there is a special box, decorated with photos of the Buggy Champ in action. The contents of that box: Essentially, it contains all the hardware and most of the main chassis pieces. Under the blister pack with the cast-metal suspension parts, we have the grey three-piece wheels. Sitting in the centre compartment in bags were the bodyshell, the rear bumper, body parts, mechanism box, and the kit-supplied ESC: At the very bottom are those famous box-art decals: And thus, the kit! It will go together in a manner unlike many modern offerings, which I look forward to! The Build The Rough Rider and Sand Scorcher were popular in their day, and the Buggy Champ and re-released Sand Scorcher also enjoyed a following. However, in over a decade since they were re-released, the supply of non-LiPo batteries compatible with the kit’s mechanism box had seemingly gone from small to infinitesimal… There are still several offset-hump Ni-MH batteries available in Europe, and I found myself importing three of them from the U.K. specifically for this model. With the first one, I had the local hobby shop (again, Advance Hobbies) produce some for me from two standard stick packs I supplied. Far away from them or any other suitable hobby shop this time, I went overseas. My experience with the first one showed me that I could not make good use of a ball differential in the back, but that the alloy chassis I had purchased was definitely useful. I found one online, and decided to pair that with a smaller metal bumper for this kit. The electronics I will be using: Pictured are an aftermarket Spektrum-compatible receiver, an old HPI SF-10W servo, an Axial RC LED module that will allow me to fit lights, and a Tamiya TBLE-02S ESC. The last-named is of great confusion to me. I clearly recall my first Buggy Champ being issued with the TEU-101BK, and thought that the original re-issue’s run (excluding Metallic Editions) predated the TBLE-02S completely. There is a thread on TamiyaClub stating that kits are not shrink-wrapped at the factory, so I have no illusions about that. However, is this really as the kit had arrived? While I was at it, I purchased some Sand Scorcher body accessories: The plan had been to use the exhaust pipe from this set on the back of the chassis, though it looks like the Buggy Champ was not issued one for good reason: it is likely not to fit with the shell on the chassis… The build will therefore make use of an aftermarket front bumper and metal chassis plate, but will otherwise be mechanically-stock. LEDs will be equipped using a leftover sprue full of light buckets and lenses from my Comical Avante build, which was a suggestion from Tamiya’s release of the sprue as its own hop-up part. At this juncture, I intend to use the kit-supplied decals, but will not use the suggested TS-12 Orange for the paint. For body colour, I actually have a few options that do not require more purchases: on hand, I have cans of TS-43 Racing Green (the colour I used for my first Buggy Champ, I think), TS-35 Park Green, TS-15 Blue, and TS-8 Italian Red. I even have enough TS-26 Pure White and TS-7 Racing White if I feel so inclined, but at present, I do not. The Racing Green would evoke my first buggy, though the possibilities of the other colours I have are compelling – a decision I am happy to mull over while I build the chassis. The rare revisit of a memory is the subject of this build thread. Onward!