Front 2nd axle gear=have you seen worse?

[dfkrug]

Safety wiring is widely used in the aviation community.

....and to a lesser extent, in auto racing.

Here is a closeup of a MFWD beveled ring gear from a JD 4300. It is also sintered (or cast steel) like the OP's gear. It is made by Dana-Spicer, AFAIK, and I have not heard of tooth failures. The surface finish is a little disconcerting. The pinion bevel gear is similar.

Older Kubotas I have repaired have obviously machined gears in their axles. I don't know about current Kubs.

 

[LouNY]

Iwas told one time several years ago by a manufactures rep that the sintered material would hold the gear lube better.

 

[K5lwq]

Iwas told one time several years ago by a manufactures rep that the sintered material would hold the gear lube better.

Sounds good to me! So now I guess our gears are superior! :cool2:

 

[Cougsfan]

Back when I was an aircraft mechanic in the Air Force we used to have to safety wire almost everything. We had to take a class to learn proper safety wiring techniques. There are a lot of wrong ways to safety wire. After you do a few thousand, you can get to be fairly proficient and fast, with or without the twisting pliers.

 

[Cougsfan]

You are right Lou, sintered metal can be made in a manner that holds lubricant. Improved wear is often touted as an advantage of sintered machine parts due to this porosity and to their structural uniformity. Sintering is a common way to make a filter media (lightly compacting and heat fusing a powdered metal, ceramics or plastics). The degree of porosity can be controlled to a extremely high level of accuracy.

Depending on the exact process and particular material used, the final sintered item may have more or less shear strength compared to forging, casting or machining the same item from billet. In other words, there is a wider quality range available due to various sintering processes that can be used (higher quality> more expense). So for use in a gear, a sintered gear it is not necessarily better or worse than other manufacturing techniques based strictly on the fact it is sintered.

If you are making a lot of parts, sintering a part can be considerably less expensive than machining a part. If you are making just a few, it is far more expensive.

The fact that these gears shown by the op don't have machined mating surfaces may look bad while on the shelf, but with a few hours of use they will look like they have been machined and will work and last just fine. To call them inferior is a totally blind call.

 

[radios1]

you can't do THIS with unmachined gears. you'd have to let them run together a few hours, then check the settings.

 

[Cougsfan]

You make a good point Radio. However what you show in the illustration is a ring and pinion differential. This gear in question is after the front axle as part of the final drive to the wheel. Granted, there are similarities but it is not exactly an apples to apples comparison. Does this gear have the same set up requirements, adjustment capabilities, loads and even the need to adjust clearances so fine? I am not sure to be honest. No doubt it would be "better" if the mating surfaces were machined. But is it really necessary? Apparently not or they would do it. I go back to my original point made a while back: value engineering on details such as this is a very real thing that a company must do to stay competitive. The machining of this gear would undoubtedly be theoretically better, but if experience in the real world shows it is not really needed, they would just be adding cost to the machine for no real world benefit. If these gears were failing right and left all over the place, you would have a point. But they are not. So apparently the engineers at the factory knows what will work and what won't much better than do us guys on a forum.

 

[mikester]

The fact that these gears shown by the op don't have machined mating surfaces may look bad while on the shelf, but with a few hours of use they will look like they have been machined and will work and last just fine. To call them inferior is a totally blind call.

Im willing to suspend disbelief and sit on the fence about self grinding gears being as good as machined forged parts. If I start seeing high volume automotive manufacturers use these gears in their diffs and offering long warranties then I will concede. I would expect to see such parts on equipment sold at big box stores with tail light warranties.

Those first OP part photos looked pretty brutal for finish...much worse than the JD parts shown.

 

[FastEddieR]

Im willing to suspend disbelief and sit on the fence about self grinding gears being as good as machined forged parts. If I start seeing high volume automotive manufacturers use these gears in their diffs and offering long warranties then I will concede. I would expect to see such parts on equipment sold at big box stores with tail light warranties.

You make a good point, however you have to look at the purpose of the gear. You are using an apples/oranges argument with automotive use. Tractors are not designed nor do they need to go 65mph in high gear for hours on end. Automobiles are not designed nor do they need to pull heavy loads, need high torque, and travel in low gear for hours on end.

 

[radios1]

You make a good point, however you have to look at the purpose of the gear. You are using an apples/oranges argument with automotive use. Tractors are not designed nor do they need to go 65mph in high gear for hours on end. Automobiles are not designed nor do they need to pull heavy loads, need high torque, and travel in low gear for hours on end.

both speed and torque has a bearing on gear life. just like machine tools, if you have the rotational speed higher, OR have the feed rate higher, the tool WILL wear faster..