graemevw 821 Posted May 9, 2019 I just found a used steel pinion in my box. It must have come on a car or motor but ive no idea what. All my cars are 08, 06 or 05. Its smaller than 06. It seems to be almost exactly 05 but ive no idea why i would have another 05 pinion. If i roll it together with a new 05 pinion they seem to mesh well, but they dont look exactly the same. I dont have another 05 with the same tooth count though so hard to tell. Is there an imperial size that is super close to 05 which this could be? 1 Share this post Link to post Share on other sites
DK308 219 Posted May 9, 2019 It's probably Pd48. 48 is almost the same as Mod 0.5, but not exact. They will mesh when you put them together like that, but a 48 should not be run on a Mod 0.5 spur. Mod 0.8 is close enough to run with a 32 pitch setup, but that's about it. 48 pitch is a very common spec, and also used in Tamiya TRF and a few other rigs. it's probably the most common pitch in 1/10 scale racing. Next step down would be a 64 pitch but that would be significantly smaller and not mesh with the Mod 0.5 at all. 2 Share this post Link to post Share on other sites
graemevw 821 Posted May 9, 2019 Ok. No idea where it came from then! Ive never had anything 48dp and only recently got a 05 car and that had a ruined alloy pinion on it. Share this post Link to post Share on other sites
graemevw 821 Posted May 9, 2019 Its the front one in both pics. Slightly bigger than 05 Smaller than 06 Share this post Link to post Share on other sites
DK308 219 Posted May 9, 2019 Dp 48 is slightly larger than Mod 0.5. Mod 0.5 equals a dp 51 and a mod 0.6 equals a dp 42. If it's in between as it looks like, I can't see it being anything but a dp 48. 1 Share this post Link to post Share on other sites
markbt73 5290 Posted May 9, 2019 Yep, that's 48 pitch (48 teeth per inch). By far the most common gear size used in electric cars here in the USA. Standard equipment for Losi/Associated buggies, and nearly all pan cars. Also used in HPI (and other?) touring cars if I'm not mistaken. I'm actually surprised you haven't come across one yet. What's funny is that it's such a standard size over here that 0.6 mod is commonly referred to as a "metric 48." Which doesn't get confusing at all. Nope, not a bit. 2 Share this post Link to post Share on other sites
graemevw 821 Posted May 9, 2019 I once had the remains of a schumacher cougar, i guess it may have come from that. Ive had 2 vintage kyosho but never swapped a motor or pinion in one. Apart from that all the cars ive owned have been vintage tamiya. Tamiya never did anything 48 did they? Ive never even acquired random boxes of bits. Ill mark it so i remember and put it back in the box. Thanks. Share this post Link to post Share on other sites
markbt73 5290 Posted May 9, 2019 So you've never had the "fun" of trying to sort out a pile of mixed 4-40, 5-40, 3mm and 2.6mm screws then, either? You're missing out... Share this post Link to post Share on other sites
graemevw 821 Posted May 9, 2019 Well, no, but i play with classic/vintage cars and motorbikes so metric/imperial mixed bags arent completely unknown. Share this post Link to post Share on other sites
Juggular 4914 Posted May 9, 2019 3 hours ago, graemevw said: Tamiya never did anything 48 did they? DN01 Zahhak uses 48 pitch. Tamiya uses all kinds of gears. Getting a pinion gets quite confusing at times. 1 Share this post Link to post Share on other sites
DK308 219 Posted May 9, 2019 3 hours ago, graemevw said: Tamiya never did anything 48 did they? I As I said in my first post, all the Tamiya race stuff, aka TRF as well as other of their higher end race inspired models such as the DB01RRR, DN01 as mentioned etc, use dp48. Dp48 is probably the most common 1/10 scale pitch world wide. 2 Share this post Link to post Share on other sites
a.w.k. 664 Posted May 10, 2019 The definition for pitch and modul is reciprocal to each other, pitch is teeth per diameter and modul is diameter per teeth. this and the conversion from mm to inch leads to the following conversion formula: pitch = 25,4 / modul, is the same as modul = 25,4 / pitch. 32pitch is 0,79375modul, 48pitch is 0,52916modul and 64pitch is 0,39687modul. So you see 32 and 64pitch are a close match to 0,8 and 0,4modul whereas 48pitch is a poor match to 0,6modul, it is closer to 0.5modul but still not good. 2 Share this post Link to post Share on other sites
DK308 219 Posted May 10, 2019 1 hour ago, a.w.k. said: The definition for pitch and modul is reciprocal to each other, pitch is teeth per diameter and modul is diameter per teeth. this and the conversion from mm to inch leads to the following conversion formula: pitch = 25,4 / modul, is the same as modul = 25,4 / pitch. 32pitch is 0,79375modul, 48pitch is 0,52916modul and 64pitch is 0,39687modul. So you see 32 and 64pitch are a close match to 0,8 and 0,4modul whereas 48pitch is a poor match to 0,6modul, it is closer to 0.5modul but still not good. You are mostly correct. But for imperial gears, pitch is teeth per inch of circumference, not diameter, measured at the pressure angle point of the teeth. When talking about gear diameter, we are dealing with three values. Root diameter, pressure angle point diameter and tip diameter. Share this post Link to post Share on other sites
a.w.k. 664 Posted May 13, 2019 On 5/10/2019 at 2:04 PM, DK308 said: You are mostly correct. But for imperial gears, pitch is teeth per inch of circumference, not diameter, measured at the pressure angle point of the teeth. When talking about gear diameter, we are dealing with three values. Root diameter, pressure angle point diameter and tip diameter. Thanks, I think I confound that, I'm not an imperial guy, i am a native metric guy Share this post Link to post Share on other sites