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I need to vent for a moment.:angry:

I've spent way too much time lately looking for 0.8mod pinions for use in Tamiya and Kyosho vintage cars.  Seems most manufacturers group 0.8mod with 32p calling them "the same".   They are close.  Very close in fact, but THEY ARE NOT EXACTLY THE SAME.  And when you are talking about mechanical tolerances measured in 0.1mm variances, it makes a difference.  You can have PERFECT gear mesh between the pinion and spur, but if they are not the exact same gear pitch, you will have extra noise and extra wear compared to when both gears are the exact same pitch.

32p = 0.7938mod

0.8mod = 31.75p

Practically speaking, DOES THIS MATTER?  For the most part, no it doesn't.  You can use 32p pinions with 0.8mod spurs and not have any trouble.  Many, many people will attest to this, including racers that really push their cars.  I'm sure there will be replies this post confirming that using 32p with 0.8mod spurs is perfectly fine.  But, if you categorize yourself as a perfectionist, anal, or autistic, it will bother you that you are mixing 32p with 0.8mod.  It bothers me.  I won't say which category I fall into.

I wish manufacturers were honest and factual when representing their products.  If the pinion is machined as 32p, say so.  It if is machined as 0.8mod, say so.  Do not say 32p/0.8mod.  It is false advertising.  The math proves this.  It cannot be both at the same time.  The machining setup required to grind the gear teeth is different between 32p and 0.8mod.  It is one, or the other.

From my research it looks like the choices for true 0.8mod pinions for 1/8" shaft motors are few and far between:

  • You can buy the butter-soft Tamiya aluminum stock pinions.  Too many to list, but they are cheap at least.  But you risk stripping out the spur once the pinion has worn down enough.  If you keep track of wear, you can avoid spur damage in most cases.

These do not last very long as most of us on this forum know.  That's why switching to a steel pinion is one of the most common recommendations to make to someone that asks "I'm about to build ______.  What hop-ups should I add to my car?"

  • You can buy the Tamiya steel pinions:
    • Tamiya 54628 Steel Pinion 17T 0.8mod
    • Tamiya 54629 Steel Pinion 19T 0.8mod

But as you can see, there are only 17T and 19T choices.

  • You can buy Kyosho vintage pinions:
    • W-5009 - Hard Pinion 9T 0.8mod
    • W-5010 - Hard Pinion 10T 0.8mod
    • W-5011 - Hard Pinion 11T 0.8mod
    • OT-23 - Aluminum Pinion 12T 0.8mod
    • OT-50 - Aluminum Pinion 13T 0.8mod
    • OT-51 - Aluminum Pinion 14T 0.8mod
    • OT-24 - Aluminum Pinion 15T 0.8mod
    • OT-52 - Aluminum Pinion 16T 0.8mod
    • OT-53 - Aluminum Pinion 17T 0.8mod
    • UM-24 - Aluminum Pinion 19T 0.8mod

Since these are vintage, they are usually a bit more expensive and harder to find.  And the aluminum ones are butter-soft like Tamiya stock so you don't want them anyway.

  • You can buy the Carson steel pinions:
    • 500013400 - Steel Pinion 10T 0.8mod
    • 500013401 - Steel Pinion 11T 0.8mod
    • 500013403 - Steel Pinion 13T 0.8mod
    • 500013439 - Steel Pinion 14T 0.8mod   <--- Yes, part # is correct.  500013404 appears to be some Audi Quattro S1 1/10 scale body.
    • 500013405 - Steel Pinion 15T 0.8mod
    • 500013406 - Steel Pinion 16T 0.8mod
    • 500013407 - Steel Pinion 17T 0.8mod
    • 500013408 - Steel Pinion 18T 0.8mod
    • 500013409 - Steel Pinion 19T 0.8mod

 

  • For 5mm motor shafts, Robinson Racing makes some high carbon steel 0.8mod pinions.
    • Their website is broken, so you can't see the part numbers for them and I don't care enough to look it up somewhere else because I don't use 5mm motor shafts.

 

So far I have not been successful in finding any Chinese manufacturers of 0.8mod pinions for 1/8" motor shafts.

I've just placed a ridiculous order ($$$) with Tony's Tamiya Parts for Carson 0.8mod pinions because there is literally no other choice, which is rather frustrating.  I live in the USA, so Carson is generally not available here except through sellers like Tony's.

Thanks for listening to my rant.  I feel a little bit better.  :wacko:

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I’ve not built anything other than stock re-re’s If you have time can you put some background in to help me follow? Playing with gears might be something I do in the future and I want to see what pain is coming...

What is the centre distance you are using and the required teeth ratio?

Is it a a single gear pair?

Is one size already fixed for size/teeth?

Is the centre distance adjustable? 

Are you re-producing original with new parts or changing the mesh for more speed?

Initial thoughts are that if by 32p you’re referring to pitch diameter, then 0.8 mod gives 25.6 teeth.. it’s that extra 0.6 tooth that makes this a Precision engineered winner :).. but in seriousness, this gear size (rounded up or down) doesn’t match the parts you’ve listed as available so I must be missing something.

Do all these manufacturers of RC parts use the same pressure angle in gears and tooth form?

Sorry for the question overload, just trying to learn a bit more about the side of the hobby that isn’t painting body shells!

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@Lee76 If im not mistaken .8 is tamiya road cars and .6 is tamiya buggy, there is also a .4 i think that tamiya uses but not sure. Althought he higher end buggies use 48 pitch pinions, DN01, DB01,TRF201....

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@Lee76  I'm really talking about the pinion to spur.  The center distance is variable because the motor can be moved closer or further away from the spur in most cases to accommodate different pinion tooth counts.

Keep in mind that gear pitch or mod has nothing to do with the number of teeth, but rather the size of the teeth.   The number of teeth, combined with the size of the teeth determines the diameter of the gear.

Here is a thread on RCCrawler forums that has a nice picture a few posts down.  You can see the difference between a 16T 32p and 16T 48p pinion.   Same number of teeth, different tooth size and diameter of pinion.

 

@Finnsllc  With "mod" sizes the smaller the mod number the smaller the teeth.  0.8mod is approximately 32p.   0.6mod is approximately 42.33p and 0.4mod is approximately 63.5p.

@E28_M5 You are correct. The Bigwig uses 0.8mod pinions.  Tony's Tamiya Parts even lists the Hotshot in the eBay description for some of the 0.8mod pinions he sells. https://www.ebay.com/itm/Carson-500013406-16T-Steel-Pinion-Gear-0-8-08-Module-Tamiya-Hot-Shot-NIP/293644659838

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According to tamiyabase most of the earlier buggies are .8 mod. It seems they changed to .6 around madcap/mantaray time.

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30 minutes ago, Champ85 said:

Keep in mind that gear pitch or mod has nothing to do with the number of teeth, but rather the size of the teeth.

I see, the 32p is an equivalent to teeth per inch.. I’ve normally specified gears with the module and pitch diameter which I thought was the pitch you’re referring to..  So if i wanted a 16 tooth gear with a 0.8 mod, its pitch diameter must be 12.8mm (mod=PD/number of teeth)  But if I bought a 16 tooth gear using the size 12.8mm in inches (0.503937‘“) is a tooth thickness pitch of 31.75 which as you say.. isn’t 32p.. click, it all falls into place. Thanks for clearing that up.. So... is this just a compatibility issue with American standard units of pitch and European convention of module? Or is the issue deeper? 

Some manufactures will provide a tooth of lets say the 0.8m 16 tooth gear but will adjust the position of the tooth radially, so the tooth thickness increases but for the same quoted module and OD, this has the advantage of increasing the tooth strength as its thickness increases. So even sticking with the same units (SI metric, sorry America) You might get different manufactures using a different modification depending on where the stresses lay or being cynical so their gears don’t Mesh properly with another manufacturer.

So I’m assuming if you’re dealing with different international standards its safe to assume the tooth forms might be different too? So measuring over pins of the various manufacturers would probably give different sizes too..

I have another question.. sorry to take up your thread.. my first build was the avante that had adjustment in the motor position. I  tried to install the motor with minimal backlash But by feel and the experience of only one build, but is there a Proper way of doing this? Do people run slight interference or go by how they sound when running? It’s something I’m never likely to experiment with with numerous re-builds.. I’ll never find out if I’m losing power or increasing tooth wear..

I think, to wrap this up.. If I ever decide to experiment with alternate gearing on anything.. I’ll just put a post on here asking exactly what I should buy...This is a very helpful place!

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6 hours ago, Lee76 said:

So... is this just a compatibility issue with American standard units of pitch and European convention of module?

Basically.  Metric vs Imperial kind of thing.   Japanese kits always used metric, American kits always used Imperial.

Kyosho used 0.8mod for their vintage racing buggies (Optima, Javelin, Ultima, etc.) until the Triumph (2WD) and Lazer ZXR (4WD) when they switched to 48p for the better spur and pinion selection for the racing circuit I guess.

Actually, I think the original Scorpion used mod 1 gears - the teeth were quite large compared to what we normally see these days.

Tamiya used 0.8mod in lots of vintage kits and still uses 0.8mod for many of their re-releases, though there is a smattering of 0.6mod as @Silver-Can said, and maybe even 48p is used for the high-end racing buggies (not sure).

I use Robinson Racing 0.6mod 23T (which are sometimes confusingly named "metric 48p") pinions in my Madcaps.  They work great.  Seriously though - "metric 48p"?  You can't make this stuff up.  It's just 0.6mod!

6 hours ago, Lee76 said:

I have another question.. sorry to take up your thread.. my first build was the avante that had adjustment in the motor position. I  tried to install the motor with minimal backlash But by feel and the experience of only one build, but is there a Proper way of doing this? Do people run slight interference or go by how they sound when running? It’s something I’m never likely to experiment with with numerous re-builds.. I’ll never find out if I’m losing power or increasing tooth wear.

Some people use a piece of paper between the pinion and spur when tightening the motor down.  Personally, I've never had good luck doing that.  What thickness paper?  There are many choices. 

I do it by eye and feel and sound.  I push the pinion to the spur until I can see and feel only a little bit of backlash between them.  The spur can visibly rock back and forth a tiny amount without moving the pinion.  I check the backlash at various rotational positions of the spur just in case it is out-of-round; the pinion might touch the spur on one side and have some space between on the other - I adjust so the tightest mesh point has a tiny amount of play to prevent binding. 

I like to try to minimize the backlash, but if the pinion gets too close to the spur the gear noise can get annoyingly loud with a high-pitch squeal type noise at various speeds when driving.  If that happens, I move the pinion away ever so slightly and try again.  It's one of those things that you will get better at with experience, but even with experience, you'll find some pinion/spur combinations that make excessive noise.  It could be due to previous wear patterns on the pinion or spur if they are used.  If the mesh backlash setting wasn't great before, the gears may have worn down at that backlash setting. Then you come along and set the backlash differently (perhaps "better"), but now the teeth are hitting each other differently, causing new noises due to the new wear pattern.  It may get better over time as things wear in.

How it sounds is perhaps a subjective thing as one person might call the gear noise "loud" while another might call the same noise "quiet".   The noise may not have anything to do with your backlash setting, either.  A great example of this for me is the Grasshopper.  The stock RS380 motor pinion to spur backlash isn't adjustable at all because the motor mount is fixed via through-hole mounts, but mine makes quite a bit of noise, at least in my opinion.  It is probably making the correct amount of noise, but I like quiet gearboxes, so I find it a tad on the loud side.  It could be due to the pinion having so few teeth that the pitch angle of the teeth just can't mesh well with the spur.

So at its simplest, I try to minimize backlash to get maximum tooth engagement, but I also try to minimize the noise.  I always grease the gears, too.  I use Tamiya Ceramic Grease for metal pinion to plastic spur or plastic to plastic gears and Tamiya Molybdenum Grease for metal-to-metal gears such as gear diffs.

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Thanks for taking the time to explain that, I have a grasshopper arriving soon, I’ll see how loud it chirps :)

 

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18 hours ago, Finnsllc said:

@Lee76 If im not mistaken .8 is tamiya road cars and .6 is tamiya buggy, there is also a .4 i think that tamiya uses but not sure. Althought he higher end buggies use 48 pitch pinions, DN01, DB01,TRF201....

I'm almost certain that most of the re re's use 0.8 mod. A few like the df01 buggys use .6 mod. However the hotshots etc of the world are .8 so I believe

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You know, I'm not sure about where you all live... But in the SW United States, we have the same problem with .6 Mod. 

I laugh under my breath when the only 2 Hobby Shops in a City of 1.2 Million People, tell me with authority "Mod .6 and 48P are the SAME exact thing". 😠😠😠😠 

OH REALLY? One will debate me till I'm blue. 

Yes, I can mail order, and there's Evilbay... But my only choice for a Steel Mod .6 is Robinson Racing. NOT that it's a bad thing... But there's shipping costs and the wait - up to a WEEK, depending on how slow these guys are.

Nearly everyone here sells the Aluminium Pinion Gears.... But I don't want a Gearbox full of Aluminium dust!!!  That's my rant on the subject.

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I just interchange them willy nilly to be honest and never had an issue although now and then they sound a bit noisy.

I've honestly had as much variation between different brand 0.8 and different brand 32dp as I have between 0.8 and 32dp though. They dont all have the same profile/pressure angle etc even though they are the same pitch.

I can well understand it driving a perfectionist crazy though, two different pitches just spits in the face of uniformity lol

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20 hours ago, Carmine A said:

I laugh under my breath when the only 2 Hobby Shops in a City of 1.2 Million People, tell me with authority "Mod .6 and 48P are the SAME exact thing". 😠😠😠😠 

OH REALLY? One will debate me till I'm blue. 

Oh really?

IMG_4628-1024-edit.thumb.jpg.5a13d266c39a908961ae1b7d263b89e0.jpg

 

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9 hours ago, Champ85 said:

Oh really?

IMG_4628-1024-edit.thumb.jpg.5a13d266c39a908961ae1b7d263b89e0.jpg

 

Oh nononono I draw the line there. I'm not some kind of sadist lol

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31 minutes ago, nowinaminute said:

Oh nononono I draw the line there. I'm not not some kind of sadist lol

:D

To be fair, that pic is 0.6mod compared with 48p not 0.8 mod that I started this thread about.   It's kind of evolved into general pitch/mod discussions and that's fine by me.

As for 0.6mod vs 48p, they are quite different and definitely DO NOT interchange with each other.  Maybe the above pic isn't a good view, but those two pinions are very different from each other.  That 48p pinion was actually installed on the motor of the Lazer ZX when I got it from the seller.  Just spinning the pinion manually on the spur made my skin crawl.  It was SO OBVIOUS that the pinion was totally wrong for that spur.  Thankfully, the spur only suffered very minor damage to the tips of the teeth and the edges as the pic shows.  I cannot imagine what it must have sounded like.  I didn't even try.  Those spur gears are expensive and I did not want to risk damaging it further!

The difference between 0.8mod and 32p is much smaller to the point that to the naked eye you cannot tell the difference.  Right now, I'm 99% sure I've got a few Kyosho vehicles with 32p pinions mounted when they should be 0.8mod.  My excuse is that at the time I thought Kyosho was using 32p and I didn't know about 0.8mod.  Plus, it worked.

Now I'm just an old fogy that likes to complain about minutia on forums.   I was really just mad that hardly anybody manufactures 0.8mod pinions for 1/8" motor shafts any longer and needed to vent about it.

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6 hours ago, Champ85 said:

Oh really?

IMG_4628-1024-edit.thumb.jpg.5a13d266c39a908961ae1b7d263b89e0.jpg

 

You'd THINK this would be obvious enough to someone who is supposed to be a TRUSTED Person... The guy who runs the Shop! 

Sadly, that isn't always the case. On your subject of 0.8/32p... They ARE much closer to the naked eye..... However, run the wrong one for at least 10 packs - and you'll SEE why. 😖

Ignorant People really ******* me off!! It's quite alright to say "I'm sorry, I don't know that" or "I don't know, but I'll find out that information for you". I can respect that.

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I remember this being and issue in the US when the Madcap/Astute/King Cab hit (I didn't know anybody with an Avante as they were too pricey). Everyone just assumed they were 48 pitch. The sounds a 48 pitch pinion gear made in a Madcap were not "pleasant". Savvy hobby shop owners were aware of what Robinson Racing called "metric 48 pitch" and would set people straight.

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12 minutes ago, Saito2 said:

I remember this being and issue in the US when the Madcap/Astute/King Cab hit (I didn't know anybody with an Avante as they were too pricey). Everyone just assumed they were 48 pitch. The sounds a 48 pitch pinion gear made in a Madcap were not "pleasant". Savvy hobby shop owners were aware of what Robinson Racing called "metric 48 pitch" and would set people straight.

That's EXACTLY where/when I learned about 0.6 Mod for the first time, over 30 years ago!! I had the Madcap and King Cab - and would give ANYTHING to have them again. I had to sell them, along with my 1988 Avante, Clodbuster, and 20 others, because we lost everything. 💔😭

But yes, the Hobby Shop owners HERE are anything BUT savvy.....

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Does anyone have experience with reducer sleeves that allow 5mm bore pinions to be used on 3mm motor shafts? I have seen them on Tower Hobbies but was hesitant to use them because I feared they may not run perfectly true. That and I can't stand making a mechanical system more complicated by adding unnecessary small parts.

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18 minutes ago, Otis311 said:

Does anyone have experience with reducer sleeves that allow 5mm bore pinions to be used on 3mm motor shafts? I have seen them on Tower Hobbies but was hesitant to use them because I feared they may not run perfectly true. That and I can't stand making a mechanical system more complicated by adding unnecessary small parts.

I've used them PLENTY of times. They don't really add that much complexity, and they're reliable. Plus, they act like a Bushing, helping to keep the Pinion Gear spinning true!! Sometimes I even use them on purpose! 😉

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23 minutes ago, Carmine A said:

I've used them PLENTY of times. They don't really add that much complexity, and they're reliable. Plus, they act like a Bushing, helping to keep the Pinion Gear spinning true!! Sometimes I even use them on purpose! 😉

Good to hear. So that would open a world of 0.8mod pinions. Seems like many of the high power 1/10 trucks and 1/8 scale in general are using 5mm 0.8mod pinions.

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1 hour ago, Otis311 said:

Good to hear. So that would open a world of 0.8mod pinions. Seems like many of the high power 1/10 trucks and 1/8 scale in general are using 5mm 0.8mod pinions.

Not only that, but if you wanted to go NUTZ, and fit, say a 3560 or 3570 Brushless Motor in a 1/10th Buggy or small Car... You can do that too!

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