Gear Materials - Compatability

[Jeri]

Hi Guys,

I was wondering if someone with a more mechanical engineering background might be able to explain the virtues and drawbacks of various metals used in gears – specifically pinion and main.

Main   Pinion
Brass   Brass
Brass   Stainless Steel
Stainless Steel   Brass
Stainless Steel   Stainless Steel
   

From a logical engineering point of view, I would have thought that having both gears the same material would have been more compatible as far as wear and maintenance goes, as the hardness and porousity factors would have been equal to the two gears.

However, we get a lot of reels where we are given dissimilar metal gears – and this is portrayed as a virtue?? As say a brass pinion gear working against a stainless steel main gear, might wear more.

A little background is that I have a load of pinion gears for a reel, made in stainless steel, and the current models are offered with a brass pinion gear, so will I enhance the performance of the reels by changing out the brass pinion gears for stainless ones – the main gear is stainless steel??

Cheers from sunny Africa


Jeri

[livinus]

Hi Jeri
I have seen pinion and main gear in all kinds of metal. Where i live (Belgium) most fishermen only use spinning reels in various sizes, even for rough sea-angling. As you can imagine, these reels take quite a beating, especially since over here many anglers seldom 'pump' their fish but instead use their reel as a crancking winch. My experience with spinning reels i serviced: in the better reels (Luxor/Crack/Mitchell...) we find a bronze main gear and steel pinion gear.
This makes sense: bronze is softer than steel but is very tough and it is good practise to make the pinion harder than the main.The pinion having fewer teeth works harder and the difference in hardness serves to equalize the rate of wear. Also this has a burnishing and cold-hardening effect on the teeth of the main gear, making those stronger with use.
Other reels often have a brass pinion and alu main, but these I found wanting in general strenght and durability.
Greetings from rainy Belgium
Livinus

[Alto Mare]

Hello Jeri.
I personally don't know much about steel , but have learned a few things along the way, by asking questions.
Here are some of the answers that I received:
1. in must cases the pinion needs to be stronger than the main gear...as livinus mentioned above.
The pinion works much harder just to get the main to turn one revolution. In some reels the pinion rotates 7 times to get the main gear to rotate one time.
2.some complain that stainless on stainless are too noisy...personally, I don't mind.

3.this is the one that makes sense to me, there is no need to have the main gear as the pinion.
Stainless steel pinion matched with brass gears should do just fine, the same goes with the heat treated stainless steel pinion (400 series) matched with non heat treated stainless steel main gear (300) series.

I would never purchase a reel that has a brass pinion and try to stay away from spinners with cast aluminum Main gears.

Sal

[Jeri]

Hi Guys,

A point of clarification - I'm not talking about 'spinners', but multipliers, and the reel in question has a brass pinion, and s/s main.

Cheers

Jeri

[livinus]

Hi Jeri
The principle remains the same: the same material for both pinion and main, or the stronger/harder material in the pinion.
Having a brass pinion and steel main is contradictory to sound engineering. I would replace the pinion with a steel one.
Greetings
Livinus

[Keta]

The piion rotates more times per crank and needs to be harder to keep it from wearing out.

Brass/Brass,  
Quiet but pinion wears out before the main gear and teeth can shear off under heavy load (bronze is a better choice).

Brass/Stainless Steel,
Probably as good as we have, strong enough and quiet.

Stainless Steel/Brass,
Not so good, pinion wears out long before the main gear but it's smooth and quiet.

Stainless Steel/Stainless Steel,  
Corrosion resistant (depending on alloy) can be rough & noisy and it tends to gall (again depending on alloy).

I will add a "dream" material.

Inconel/Iconel,
Highly corrosion and wear resistant, quiet/smooth, very strong, no galling but hard to machine.

[Jeri]

Hi Sal & Livinus,

Thanks for your replies. That all makes perfectly good sense, BUT!!!

Here's the issue – a perfectly good reel, one that we have been using for over 3 years down here in southern Africa, which has through that time developed a solid reputation as a fast casting, and robust reel that has no design issues or flaws after such a time of our hardworking environment – has a brass pinion and a stainless steel main.

To date, and we were the first in Namibia to start using these reels, we have never had any issue with pinion gears wearing – even as an authorised service centre for that marque. The reel was the Finnor OFC series, and while they had a slightly more expensive 'brother' off the same production line in the Quantum OFC, the slightly cheaper model excelled. The Quantum model for the few extra dollars had an end float bearing rather than a bush, and a stainless steel pinion gear – hence the price difference – but both superb reels.

Now we have the upgrade of the Finnor just hitting our shores, and on immediate inspection of our delivery – I find that while they have improved the spool bearing quality to ceramic hybrid, and added an end float bearing rather than the original bush – the entire component schedule remains exactly the same, including the brass pinion and stainless steel main gears.

These are the higher speed models so have a retrieve ratio of 6.2:1, hence the pinion is working seriously hard – so the question is – why haven't we had a problem?

It's not as if we aren't working them hard with heavy duty casting, wading and used fully submerged in the surf, and cranking in sharks well over 100kgs. Usually we find that our environment throws up the core defects in various models after a couple of years, but this has not been the case with these Finnors.

It does make you think, that while the logic of your observations is perfectly sound, perhaps we are not quite as smart as the designers??


Cheers from sunny Africa


Jeri

[Alto Mare]

Hello Jeri.
As I always say, the proof is in the pudding and looks like you guys are doing a good job at that, by really giving the brass pinions a workout.
As stated above, I'm not an expert on metal and I am going to step aside and let others smarter than I am answer.
As most of us know, the base metal for brass is copper.
When copper is mixed with zinc it becomes brass, now the percentage of zinc will determine the strength.
From what I've learned, the highest percentage of zinc added, the stronger the brass will become, but at the same time more prone to corrosion.
There are other metals that could be added including compounds to help with corrosion, but here is where I'll step aside and let someone else chime in.

A while back a machinist mentioned to me that brass gears could be just as strong as stainless steel gears, but it all depends on the serie/grade.
With that said, if you were to ask me to replace all of my heat treated stainless steel pinions, I would kindly tell you no, thank you.
The bottom line is that steel is much stronger than brass., what are they trying to achieve by using brass pinions? I don't know, but would love to learn.
Take care Jeri.
Sal

[Keta]

Jeri, Are you sure they are not bronze rather than brass?

[Alto Mare]

Are you sure they are not bronze rather than brass?

Lee, you're forcing me to learn more :
I just read a little about bronze, interesting that 65% of copper mixed with  30% of zinc and only 1% of tin would make it that much harder than brass, which is usually 65% copper and  35% zinc
Comparatively, brass is a very soft metal. For example, it is used for plumbing fixtures because it is easy to work with and easily tooled. Brass is not as hard as bronze.  Brass  is also prone to corrosion, so most plumbing fixtures are coated with another metal such as chrome to make it more durable.
Bronze on the other hand is very hard and can last forever.  In fact, there are several grades of bronze. A type called  admiralty bronze was used for cannons and is used for propellers on boats.  
I've also looked up the alloy ZT, way too much information...have fun with this guys, I'll be listening

[bluefish69]

Sal

If you would like to play with a Fin Nor OFC 20 4.3 Gears. I have one in good working condition that I would let you borrow. Box & all papers. I enjoyed this reel fishing in N.H. for Cod in up to 400' H2O.

[Alto Mare]

No Mike, but I thank you for the offer. If you like them, that says a lot.

[Jeri]

Hi Guys,

Now I'm really confused. Checked the Finnor web site, and on the OFC (original) the pinion is quoted as brass. Then on the latest LTC, it is quoted as bronze.

Went back to the workshop – took the LTC apart, and compared the new pinion gear to a brand new spare that I have for an OFC, and they look identical, colour, machining, everything. Sure I haven't the machinery to check the chemical content, but to the naked eye, they are identical.

Now it has me wondering whether the folks writing the sales spec information are honest. Bronze in the OFC would answer the original question of longevity, strength and lack of wear.

Cheers from sunny Africa


Jeri

[johndtuttle]

Hi Guys,

Now I'm really confused. Checked the Finnor web site, and on the OFC (original) the pinion is quoted as brass. Then on the latest LTC, it is quoted as bronze.

Went back to the workshop – took the LTC apart, and compared the new pinion gear to a brand new spare that I have for an OFC, and they look identical, colour, machining, everything. Sure I haven't the machinery to check the chemical content, but to the naked eye, they are identical.

Now it has me wondering whether the folks writing the sales spec information are honest. Bronze in the OFC would answer the original question of longevity, strength and lack of wear.

Cheers from sunny Africa


Jeri

I would say that your experience tells you they possibly got it right the second time?

Very likely that someone put in an error they were brass, but corrected it in subsequent literature, particularly as they have gotten some pushback on other sites from people with the same questions.

Depending on the alloys and treatment involved, Bronze can be harder than stainless. As well, as I understand it, having differing levels of hardness in the gears actually decreases wear as one "gives" (bends microscopically) rather than wears from contact with the other. When you hear gear noise it is wear though, hard stainless holds up very well of course.

[Islandgypsy]

In the marine industry we always use "Silicon Bronze" (?) fasteners. Very hard and durable in the marine enviroment...brass would melt away to green putty below the waterline.