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Discussion Starter · #1 ·
the new black arrow car has a conical pinion and gear set up. is it like the old brass setups or is it to get perfect gear mesh with a normal toothed crown gear. or move it off centre. is there an advantage over the old brass setups, where you have a lot of contact area. john
 

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Hi john.
The idea has been around a long time!
They appear to be using a conical pinion, with a conventional looking crown gear. The theory is; You can perfect the mesh by simply moving the pinion up or down the motor shaft. Its another way of getting around the various TPI that the plastic Slot car makers use with their gears. The most popular way to acheive this, with inline set ups is the Crown gear and motor shaft spigot being 2 parts, as per the latest Scaleauto offerings and MB Slot have been making there crowns this way for a while.
Going back a few years, Ninco did a similar thing with its first series Pro Race A/Winder gears, a conical shape pinion was supplied with each gear set.
Regards Bill.
 

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Bevel gears can be made with the centres in line or with off set centres. (The off set ones are also known as hypoid )

Theoretically a crown gear and parallel pinion isn't a very satisfactory gear arrangement because the teeth on the crown have to get closer together as they get nearer the axle, the teeth on a parallel pinion don't. That means the pinion teeth can only be the correct size for the crown at one diameter. Making both gears conical means they can be made so the teeth match properly across their complete width.

Bevels should be better and if you look inside how 1:1 car transmission turns the drive through 90 degrees and you'll find they almost always uses some variation on bevels.
Bevels have been used many times before on slot cars. Getting the length ways position of both axle and pinion correct is important to getting bevels working correctly, where as it doesn't matter much with parallel pinions. Crown gear and parallel pinion set ups seem to work well enough on slot cars whatever the theoretical disadvantages.

How well a particular make of slot car gear works largely depends on the quality of design, manufacture and materials rather than the basic type. Anybody like to offer any experience of Black Arrow

EDIT Looks like Bill and I were typing replies at the same time - fortunately we don't seem to conflict
 

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Discussion Starter · #4 ·
hy, ive got a hypoid crown gear thats running with a 3/16 offset and a paralell pinion, and its whisper quiet. using the old *** paper to set the backlash. i,ve also got a brand new o/s 3-1 bevel gear and pinion with a 3/32 bore and 2mm pinion. that i,ll use on an indy offy body that i,ve got. 300, i dont get the bit where you say" that means the pinion teeth can only be the correct size for the crown at one diameter". you,ve lost me a bit there. could you elaborate for me. i know slot it crowns arn,t strictly speaking a 48 pitch, but with clever engineering to allow different tooth pinions in the 5.5mm dia to mesh perfectly well. i believe that a conical pinion on a normal crown, allows you to run a certain amount of offset, is that right?. john
 

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Hi John
I'll have a go at explaining what I meant.
Imagine a crown with a 60 mm outside circumference and 30 teeth. The teeth are 2mm apart.
Imagine the teeth go in for 10% of the diameter, The circumference of the inner end of the teeth is 54mm but there are still 30 teeth. So the teeth are now 1.8mm apart.
The best you can do with a straight pinion is to mesh with teeth 1.9mm apart, that's not quite right at the outside where the teeth are 2mm apart nor at the inside edge where the teeth are 1.8mm apart.

Did that make it clearer or leave more confusion?
 

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Discussion Starter · #6 ·
HY 300, IF YOUR TALKING STRAIGHT PINION MESHING WITH CONICAL GEAR I UNDERSTAND,IF NOT I,M REALLY CONFUSED! does anyone know about using a conical pinion to offset the crown gear john
 

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Please learn the difference between a comma & an apostrophe; comma's look like this, & are on the bottom row of keys, next to the "m" on a "qwerty" keyboard.
Comma
The apostrophe is next to the "enter" key, & has very different uses.
Apostrophe
It may be confusing because they look similar, but they are very different in application & it is very confusing to read your posts when you use one for the other.
Thank You.
 

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Mike Newns
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QUOTE (martini917k @ 21 Aug 2012, 12:01) <{POST_SNAPBACK}>Please learn the difference between a comma & an apostrophe; comma's look like this, & are on the bottom row of keys, next to the "m" on a "qwerty" keyboard.
Comma
The apostrophe is next to the "enter" key, & has very different uses.
Apostrophe
It may be confusing because they look similar, but they are very different in application & it is very confusing to read your posts when you use one for the other.
Thank You.

I,M instead of I'm - you are easily confused.

Mike
 

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1 hp Trabant is not my real car
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QUOTE (martini917k @ 21 Aug 2012, 14:01) <{POST_SNAPBACK}>Please learn the difference between a comma & an apostrophe; comma's look like this, & are on the bottom row of keys, next to the "m" on a "qwerty" keyboard.
Comma
The apostrophe is next to the "enter" key, & has very different uses.
Apostrophe
It may be confusing because they look similar, but they are very different in application & it is very confusing to read your posts when you use one for the other.
Thank You.

Martini - we are here to talk about slot cars, not nit pick grammar.
But while you are in your glass house...comma's denotes the possessive of comma. (i.e. comma's usage, the usage of a comma).
the plural of comma is commas.

Now, back to gear teeth,

Tom.
 

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Discussion Starter · #10 ·
Its a bit sad really. anyway! does someone know the answer about using a conical pinion to run an offset on a standard crown gear. john
 

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1 hp Trabant is not my real car
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John, if by offset, you mean the shaft of the pinion is not on the same plane as the shaft of the crownwheel - not intersecting, then you will need hypoid gears. Straight cut gears, conical or not, would not mesh.
Tom.
 

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Russell Sheldon
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There has been an interesting discussion on this topic on Slotblog. When I asked the question: "Could someone please explain the benefit of using tapered pinions with an inline set-up?", the reply I got from some of the world's foremost slot racers was rather vague, to say the least. But they all use tapered pinions with their offset inline set-ups, with excellent results.

Here's the link to the discussion: http://slotblog.net/topic/33675-hypoid-vs-non-hypoid/

Now, if anyone can tell me why the Eurosport racers all use 72DP pinions with 64DP gears, that would enlighten me further!

Kind regards,

Russell
 

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Tony
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They also us 72dp pinions with 80dp gears and it does work as that is what I have on my GP12 saloon. Why it works I don't know
 

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QUOTE (stoner @ 21 Aug 2012, 09:21) <{POST_SNAPBACK}>HY 300, IF YOUR TALKING STRAIGHT PINION MESHING WITH CONICAL GEAR I UNDERSTAND,IF NOT I,M REALLY CONFUSED!
I was talking about crown gears (Not conical gears) and straight pinions.
Sorry if the description doesn't help - guess a drawing would make it clearer, unfortunately my drawing skills would need some honing.
 

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QUOTE (Russell Sheldon @ 21 Aug 2012, 16:10) <{POST_SNAPBACK}>Now, if anyone can tell me why the Eurosport racers all use 72DP pinions with 64DP gears, that would enlighten me further!
All the Eurosports tech charts I've seen recently shows the finalists using 80 pitch spurs and pinions.
Where do they use a 72 / 64 mix?
 

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Dennis Samson
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My experience in Retro racing is that the tapered pinions are more accurately machined than most of the straight pinions, and therefore give a better mesh. There may also be some benefit when running the large amount of hypoid offset that many of us do (around 1.3mm). Certainly I can get much smoother, quieter mesh with a tapered pinion.

What I haev found when using a 72DP pinion with a 64DP gear is also in inline racing with large hypoid offsets. I have used the aluminium Sonic drag gears (64DP) with straight cut Sonic 72DP pinions, and that also gives a nice smooth mesh. The reason I think is that the effective pitch of the gear as it meshes with the pinion in a hypoid setup is smaller than true 64DP. I think the guys running 1/32 F1 Eurosports do the same for the same reason.

I have not seen anyone running 80DP pinions on 72 DP gears in an anglewinder setup, but I would think that if there is a combination of a big angle and a fair amount of offset of the pinion below the gear, the same theory would apply.
 

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What's 1/32 F1 Eurosports?
Internationally, Eurosport is a sports car class for unlimited motors, although the motor position is unlimited they are almost always low angle angelwinders
Most but not all 1/32 F1 rules require inline motor position. Different rules have different motor limitations.
 

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Discussion Starter · #19 ·
hy Eddie. the link to abslotsport was exactly what i meant and also answered my question. thanks. even the gear sellers recomend different pitch matching. bit beyond me, that one. but i,ll tell you what doesn,t match, an 8t 48p pinion to a 50t 50m pitch sidewinder gear as i tried that combo with a 46000rpm king motor in a carrera 1/24 hot rod. john
 
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