12 replies to this topic

[Pablo]

If I were to use a Slot.it spur GA1630E (30 tooth/16mm OD) and a Slot.it 10T pinion, my choices appear to be:

 

-PI10  5.5mm

-PI6510E  6.5mm

-PS10  6.5mm

 

The "E" indicates "ergal" I guess but it seems ergal means possibly the cuts of the teeth as opposed to the set screw arrangement?

Does an "ergal" spur require an "ergal" pinion? If so the choice would be the PI6510E I guess.

 

Also, the PI6510E appears to be steel instead of brass in the catalog photo.

Is it a press-on like the others?

 

I'm experienced with the crowns but never used one of their spurs, until now. Thanks,

 

Pablo

[Pappy]

Pablo,

 

Use a ScaleAuto 17.5mm spur gear and a NSR Lightweight (6.5/6.75mm) brass pinion and you'll never have a problem with the gears.

[mickey thumbs]

Slot.it usually uses the brass 6.5mm 10T for SW and AW 1/32 applications. The 5.5mm is for their inline motor pods. They make pinions and spurs out of an aluminum alloy called ergal.

From a google search:

Ergal is the strongest aluminum alloy. Suitable for challenging and complex applications in aerospace, marine and industrial sectors. 
 

I stick with the brass and plastic because I find the ergal noisy and with the low torque and rpm motors commonly used in 1/32 scale (compared to 1/24) I don’t feel the need for the extra strength.

I think the noisiness of the ergal gears may be due to the slightly variable pitch used in 1/32 to enable different tooth combinations to work with a fixed diameter spur to accommodate the fixed motor shaft-axle distance. It seems less of a problem with the brass and plastic gears.

[Courtney S]

If youre using a 30 /16mm spur gear I strongly recommend you use the 6.5 pinion in brass. I agree with Pappy I like NSR pinions, but I also like NSR gears to match, but I have used scale auto slotting plus and slot it without any problems.

[Pappy]

Courtney,

 

I used an NSR aluminum spur gear, an NSR brass pinion in an NSR motor pod in an NSR chassis in a 6 hour endurance race and the spur gear chewed up the pinion "twice". Never gain.

[Pablo]

Thanks guys    Pappy, your 17.5 mm spur would be too big for this particular build, but thanks anyway 

I need 16.6 mm or smaller.

 

Thanks for the ergal info, etc. Mike and Courtney.

 

Plastic 16mm/30T non-ergal spur, and a 10T brass non-ergal 6.5 mm pinion it shall be 

[Dave Crevie]

The downside to the Slot-it, etc. spurs and crowns is the smaller set screw. They work fine for most home set cars because of the softer axles. With commercial axles you absolutely have to flat the axle. I used to re-thread the set screw holes for the bigger commercial set screws.

 

The gear pitch is metric, and the equivalent to english 50 pitch. 

[Pablo]

I can drill and tap it if I need to. I've done it on the crowns many times

[Ramcatlarry]

FYI: ALL metal on metal gears require some lubrication.  The softer one will usually fail without it.

[Bill from NH]

A thin grease like Lubriplate works well. We used that with Faas bronze spurs & steel pinions.

[Dave Crevie]

Again, using gears with matching tooth profiles is most important. Mixing gears with different pressure angles is death. You will be lucky to get a full race in, regardless of what lubricant is used. Stick with the same manufacturer for both gears.

 

This animation shows the interaction of the gear teeth as the pinion drives the larger spur gear.

 

https://geargenerato...,0,0,0,0,3,1114

 

 

Gear tooth geometry;

 

 

 

The pressure angle is the line drawn through the point of contact between the teeth when it intersects with the pitch diameter, and is 90⁰ to the  pitch base circle.

 

 

Kicking the motor over on an angle is never a good idea with straight cut gears. You need bevel gears for that, or live with the high wear on the gears.

[Pablo]

Thanks again everybody for the help. The Slot.it gears arrived and I did a mesh test before starting to build.

Tack soldered a jig motor into an old TFlex chassis using the gears, and spun it up.

 

 

Butter smooth. Incredibly, it drew slightly less amps @ 3V with the spur in place than without 

[Dave Crevie]

Angle spur. Good choice. You may find a slight variance in draw dependent on gear mesh. There is a sweet spot, and if you don't know the profile specs on the gear teeth, you can only find that by trial and error.