How to make Aluminum and steel gears work together?

[Losmosis]

I am faced with a problem of using an aluminum pinion gear and a steel spur gear. This project is time sensative. In other words I have no time for Hard coating the aluminum gear.
Can anyone suggest how to prolong the life of the Aluminum gear.
These gears have a fair amount of torque on them and move at a relatively hi RPM. I can't give exact #'s to rpm and torque because I simply do not know.

As of now I can get somewhere around 12 minutes of use from the aluminum gear and need to extend life to 35 minutes at least.

I hope someone can give me some information to make this possible.
Thank you.

 

[sreid]

Possibly oil with high pressure additivies (like 90W automotive differential oil). Possibly Molybdenum Disulphide additives. It you have to end up using a surface treatment, consider General Magnaplate Tufram.

http://www.magnaplate.com/pdf/engineeringdataguide9.pdf

 

[israelkk]

What happens after 12 minutes?

 

[diamondjim]

Have you tried adding graphite to the lube.
It may seal the pores in the aluminum.
Why can't you tuff coat the pinions?
12 minutes even to 35 is really a short
life. Must be very expensive.
How high of an rpm? Relatively high means
nothing to anyone as it is a subjective
statement.

 

[Losmosis]

After 12 minutes the gear is worn out. beyond futher usage.

I have thought about the graphite lube, just have not tried it yet.
These gears are exposed to dust and dirt. They are not sealed inside any casing.

I can't tuff coat the pinions because I have to have everything done by this thursday, and I get my second batch of new gears on Wed. no time to have it done.

The RMP's are varied, at idel 10,000 at full throttle 33,000.

I plan on having the gears cut from steel in the future but for now time just doesn't allow me to do it.

Expensive? a little but not bad the aluminum gears are $4.75 a piece and I use 2 at a time. So I have 4 sets to use for the weekend of racing.

This is in a R/C application however don't be fooled into thinking that these gears don't see a lot of RPM and stress.
They are driven by a Nitromethane engine producing around 3.5 HP and pulling a 13.6 lbs vehicle. with on throttle jump landing, bumps etc. This drive train really takes a beating. We often break Titaninum turnbuckles, ball studs etc.
The final race will be 30 minutes long with a 5 minute warm up so 1 set of gears will have to last 35 minutes.

 

[unclesyd]

Checkout this product, Molykote 106, a bake on material. See if you have a distributer in your area and if not contact the nearest one and UPS Red the material. The techical people at Molykote used to be very helpful and of all things nice.
Once this material is applied to both gears still use a high EP Oil even though you want get much lubrication at your RPM.

http://www.dowcorning.com/applicati...sp?L1=003&L2=00000792&L3=&L4=&L5=&PG=00001016

 

[Losmosis]

Thanks I will give it a try.

 

[Losmosis]

Then again at $75 a quart. It's a little pricey for the application.