- This topic has 66 replies, 7 voices, and was last updated 4 years, 1 month ago by
.
-
Posts
-
Gear Pitch
Ary wrote a terrific article on gear pitch 10 years ago that everyone should read: http://austinslotcarclub.com/forums/topic/gears-pitch-mesh-a-look-into-slot-it-variable-pitch-gears/
With the diameter of Slot.it pinions fixed, the pitch varies with the number of teeth, while all Slot.it crown gears have a fixed pitch of 48; their diameter changes. For that reason, the optimum Slot.it gear mesh is achieved with an 8 tooth Slot.it pinion. 9 tooth is OK too; 10 tooth is marginal, and 11 tooth should be avoided. I do not know the pitch of NSR pinions and crowns to know how they compare to the Slot.it gears. The pitch of the NSR gears can be calculated by using the formulas in Ary’s article.
This is a separate issue than allowing Slot.it gears in the NSR cars, but if anyone does so, the pitch should be calculated to see how well disparate gears will mesh.
Russell
The Pitch of the NSR Pinions, Crowns and Spurs are in the ’48’ range.
http://austinslotcarclub.com/nsr-gears-pitch-table-1/This is quite common in 1-32 scale gears. The tooth shape of the smaller Pinions is like a tulip or a vaulted-arch. As the tooth count increases, the shape morphs to an “I”. On the drive (Crowns, Spurs, Contrate) the tooth shape is mainly a straight sided Triangle. On Offset Crowns the teeth become slanted so they can mesh easier with the pinions non-angled teeth (similar to a 1×1 differential gear).
USELESS TRIVIA
Whereas in the current 1-24 world, “Coarse” gears are 48p, and “Fine” are 72p.
yet – the most popular in current 1-24 land is 64p (medium) since it has a finer-Lash than 48p but does not Shed as fast as 72p.
If the pitch gets “too fine” (e.g. thin “A” shaped spikey teeth with “V” valleys) they can strip very easily by gunning the motor or during a crash that impacts the tire/wheel assembly (e.g. the motor grinds the pinion into the plastic when the wheel stops after hitting another car or the Wall).Hence – in the 2021 NSR Catalog (pg27) you see a 8z(teeth) steel pinion (#7408) with a longer “hub” and 64-pitch rating. That pinion is designed to be soldered onto a 2mm motor shaft and meshed to a 64p Spur (flat or 5%-beveled); mounted in an Angle-winder orientation (pinion on left side; clockwise/righty rotation).
"... get on your bad motor scooter and ride!"
Sammy with MontroseI was a little slow to process the data. Since the Slot.it and NSR pinions have the same diameter, each pinion will have the same pitch as their counterpart in the other manufacturer. Eight and nine tooth pinions will have the best gear pitch; ten and eleven tooth pinions should be avoided.
Russell
I had forgotten about Ary’s followup on NSR gears. It just goes to show how much information is in ASCC files.
Russel
Russ – I had to double-check myself to make sure there were tables for both Slot.IT and NSR. And – to your point we have some Great assets; I always stumble across a reference to one of Ary’s How-To videos or one of our Forum posts when searching the interweb for slot-car 411 🙂
"... get on your bad motor scooter and ride!"
Sammy with MontroseDavid posted on the home page – I spent a lot of time Saturday running my F1 with new NSR gears had no problem it ran very smooth. NSR gears is what we will use for this race.
AS OF THE CLUB MEETING 9/25 – the members present voted Aye/for and David approved the use of the Slot.IT inline crown gears.
MANDATORY: Slot.IT crowns can only match the tooth-count(z-number) offered by NSR;
24, 25, 27
RPMs: using the stock 10z pinion: at 11v: 27/10= 7265 25/10 = 7847 24/10 = 8174
RECOMENDED: Brass/bronze vs. Alloy/aluminum // brass seems to wear less.
Important Note: NSR motors are setup to turn Counter-Clockwise (lefty) vs. Slot.ITs which turn CW/righty – looking at the motor from the pinion end. If you install a crown with the plastic gear bed on the right (looking at the pinion end) the car will run Backwards, and you’ll notice a slightly smaller/tighter open area in the gear box. DO NOT ‘fix’ the problem by swapping motor wires – you are now messing up the Advance (deg.) the motor has built into the Armature. You are also now running the armature backwards (from any break-in from the factory or when you prepp’ed it).
Some 4-40 grub screws are a little too long in the arbor/collar of the gear and can hit the motor or pinion.
/** To Series Manager Dave Cass and ASCC members; my sincere thanks for accepting the proposal to run Slot.it crown gears as an option to the NSR gears for the F1 series. These gears will make the F1 car smoother and more reliable. Ran over 200 laps today with no issues. Tip: Have added significant weight. These cars in the right hands are sub 3.8 possible. John/Lotus-JR **/
"... get on your bad motor scooter and ride!"
Sammy with MontroseGREEN CHASSIS WEIRDNESS
Using a green ultra-hard chassis, the holes for the top Axle-grubs were tight and useful – for M2 allen grubs.
BUT the Bottom holes were so loose, I had to carefully drill a hole large enough for a 4-40 (the typical NSR grub screw) and installed the brass upgrades. CAUTION there is barely enough ‘meat’ in this area to allow the 4-40s. This was only My experience and fix; “your mileage may vary”; “caution – coffee is hot and should not be placed between your thighs”; “don’t take stellara if you are allergic to stellara”.
ESSE TURN CLIMB – the climb-out likes to porpoise the car out of the slot when entering the back ‘straight’. A 1/2-mm to 1-mm flying gap with a slight bit of axle slop seems to prevent the Pop-out. 3/4 to 7/8 mm was the range my particular car seemed to “like”.
I also added a 3 gm lead disk behind the guide.
"... get on your bad motor scooter and ride!"
Sammy with MontroseI’m glad we decided on NSR. I also bought a Policar to test, but only swapped the chassis today, long after the decision was made to run NSR. The wires to the guide are quite a trial to get from inside the body to the guide due to tight clearance. Here is a picture of the two on the track today. Quite a possibel 1/32??? debate.
Attachments:
Front Axle Grub Screws
I had the issue with the lower front axle grub screws not holding in the chassis; the grub screws would just spin. I took several strands of copper guide braid (maybe 6 or 7 strands), twisted it together and put it in the grub screw hole, with the end of it sticking out, and screwed in the grub screw. This seemed to make it hold. It stayed firm through the race last week.
Russell
Russell and All – The NSR replacement chassis’ I received run two different grub screw sizes. The lower grub screw is the standard NSR sized grub screw while the upper one is a Slot.it sized grub screw. When installing the lower NSR grub screw it feels like it’s too big and will break the chassis but they do fit. The chassis will budge out a little but that is the correct grub screw to use. There are no issues with the upper grub screws.
I don’t know if this is consistent with all the chassis but it is for the three replacement chassis I received. Of the three chassis I purchased – one green and two white – the green one did not come with grub screws but both white ones did. The screws that came with the chassis were two different sizes.
So is the “standard NSR sized grub screw” the NSR 1238 M2.5 grub screw or the NSR 4809 M3 grub screw?
Russell
Officially, NSR intended these to be M2 (i.e. 2mm diameter) holes, hence the useless 2mmL x 2mmD (b/c they are Too Short) pack of M2s that should be included in your jewel case.
IMHO – this decision makes no sense from NSR (e.g. does not really make the chassis “uglier”, or lose performance, to make the uprights fat enough for their typical 4-40 screws).
My first black/medium chassis accepted the M2s and I have SCC 4mm Oval-heads on the Top and Bottom.
PER MY PREVIOUS POST #16963, on my Green/X-Hard chassis the top axle adjustment screw holes *were* tight enough for M2s, yet the Bottoms were loose, forcing me to use 4-40 brass grubs (very carefully).
NOTES My new LEB Hobbies car, has wide bottom holes (needs m2.5 or 4-40). Yet – I have another spare black chassis that Is Tight Enough for the M2s (WTH?)
For the bottom – if you have M2.5 grubs (from Thunderslot?) they *may* be the perfect solution.
Otherwise you may want to TRY USING 4-40s (i.e. normal NSR, i.e. use a 0.50 wrench).
The English bit size is: 7/64 (i.e. 0.1094) which is just small enough that the 4-40 (i.e. 0.1120) can Bite into the plastic and hold.
Using the 4-40, you will see the stretch-marks, but unless you are ham-fisted the risk of damaging the chassis is Moderate. Take it slow and careful, one side at a time.
"... get on your bad motor scooter and ride!"
Sammy with MontroseNew NSR F1 rule
A new rule has been added to the NSR F1 Race Rules Page. Maximum overall axle/tire width is 68mm. This will be the limit for both rear and front axle/tires. I hesitate calling it a track width because, usually, track width (at least on 1:1 cars) is defined as the width, wheel center to wheel center. For our purposes we measure the overall width, which will be sidewall to sidewall. There was no max width specified in the original rules.
With cars with enclosed bodies, the maximum width is limited to the width of the body (and adjustments made if a car’s body is out of scale). With open wheel cars, we should probably always have a max width specified.
This new rule will be implemented with NSR F1 race #3; the results of the first two races will stand, as they were raced with the rules at the time.
- You must be logged in to reply to this topic.