Offshoreonly.com - What steel to use

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- Drives and Lower Units (https://www.offshoreonly.com/forums/drives-lower-units-217/)

- - What steel to use (https://www.offshoreonly.com/forums/drives-lower-units/353689-what-steel-use.html)

If you have another oem gear take it to a place that does steel analysis (search chiarpy v notch testing). They can tell you what it is and the hardness . In Canada it costs about $125 for this.

All the stuff I have read say near nap forged gears but it doesn’t say what type of steel or treatments used. I know you don’t want to hard of steel cause it was just shatter and you don’t want to use soft either . I do have original set I did get them tested for Rockwell I believe it was 65 Rockwell. I’m getting the program made out right now to make the gears just have to decide what kind of steel to use

Aermet 100 is my go to material choice if I keep braking other things inside a transmission. It aint cheap but it seems to hold up to the abuse.

from what I understand is Richmond Gear used to make them back in the day and they were solid
then new owner didn’t want to pay the price tag on them and went to Israel for gears ??
now u got problems!!!

I ordered 9310 steel we’ll see how turns out

I will call Richmond gear and see what they know about stern powr

I'm not a metallurgist but I've been around material testing for more than 40 years, so I know a little.

I think a lot of this will be about your manafacturing and finishing process and how you want the gear structured. For example; a more ductile base with a hard surface, etc. Base metal selection is important, process, and treatment/finish process such as heat treat, cryo, quench etc is just as important, you'll again need to consider your manufacturing process, are you going to forge the blanks then cut them, is it a block and CNC'd, and how your physical manf process will effect the metal vs the end product you want.

You might want to talk to a metallurgist as it gets complicated quick.

Heat treating aligns the grains of the metal but different heat treat processes create different results. A lot of the time heat treat is used to relieve stress created in Manf due to localized heating such as welding so even just the heat treat needs to be spec'd and checked to make sure the process is yielding the desired results. Some times the heat treated cuts corners and gives you back an interior result.

Why don't you start with what the problem is your trying to solve is by making gears out of different base metal?
1 ) Is it cracking, sheering, excessive wear, etc
2) I assume your making no design changes to the gear itself, just remaking the exact same part?
3) Are there others gears that mesh with this gear(s) and what metals are they made out of and finished and how will the two interact.

You might be creating more problems than your solving or you could just make em, run em and see what happens.

Either way good luck, post up the results.

You could also call big silver cats company and see what they say about the gears for you.
https://www.offshoreonly.com/forums/general-boating-discussion/335303-start-finish-building-our-50-skater.html

Did y’all get the gear thing figured out ?

If you are still interested, my neighbor just had a batch made for Bravo drives and did a ton of research on the subject, they will be getting installed this week for some real world testing.
PM me your name and number and I will have him give you a call.

Have you looked at using S7? I talked to several people who would know about their opinion on toughest most durable steel and consensus is that S7 is the way to go. If you are already making gears, you need to talk to George at AADS (517) 858-1123. He does a lot of high performance drive builds, he is an expert on the subject.