[rob_macca67]

Guys.....

Firstly, I know that R&P's usually only come as a "matched" set, but I was wondering "if" u can interchange between different sets?
I currently have a 5.12 R&P set that has a broken Pinion (usually has 8-tooth but mine has broken teeth) and the Ring (41-tooth) for this set is still good condition.
I also have a 4.625 R&P set that are both in good condition but 4.625 is no good to me (ATM). With the 4.625 set, the Ring has 37-tooth and the Pinion has "8"-tooth.
Now, here's the question to those in the know....... is it possible to take the Pinion (8-tooth) from the 4.625 set and use it with my good 5.12 ring(41-tooth) to make a complete 5.12 R&P set again?
Do I need to send it to a diff-lapping expert for them to lap the 2 together this to happen?

cheers...
rob

[mnemonix]

Even for identical ratio's, the pitch/bevel/curvature of the gears need to be reground to be used as a pair.
This is needed at a minimum to ensure the diff remains strong/silent with a proper contact pattern.

I'm unfamilar with the gears you're dealing with, but i'd be doing more than counting the gears. Compare the diameter of the pinion at the very least before finding a shop to lap them for you.

For what it's worth, I'd be getting a used pair and using them. It would most likely be the cheaper option as milling hypoid gears isn't something many workshops will be able to do.

[303zuke]

rob_macca67 wrote:

Guys.....

Firstly, I know that R&P's usually only come as a "matched" set, but I was wondering "if" u can interchange between different sets?

....... is it possible to take the Pinion (8-tooth) from the 4.625 set and use it with my good 5.12 ring(41-tooth) to make a complete 5.12 R&P set again?

cheers...
rob

The answer is a BIG NO! Even though both ratios have 8 gears on the pinion gear, they are cut at a different dimeter and angle to specifically match the teeth on the ring gear.

As you yourself have noted, the ring gears have 37 and 41 teeth. To fit this number of teeth on a ring gear of a certain dimeter and size, the teeth must be cut at a different pitch (the spacing between different teeth). This then involves changing the height of the teeth and the angle of the faces, and usually the thickness of the ring gear. All these differences mean that the gear teeth on the pinion gears will also have different forms and the "cone" shape of the pinion will also be different to suit the thickness of the ring gear.

As mnemonix said, even gears of identical ratios (and therefore design) need to be carefully lapped to ensure proper mesh and clearance for proper contact and long life, and it's best to keep them as matched sets even when in used condition.

[rob_macca67]

303zuke wrote:

The answer is a BIG NO! Even though both ratios have 8 gears on the pinion gear, they are cut at a different dimeter and angle to specifically match the teeth on the ring gear.

As you yourself have noted, the ring gears have 37 and 41 teeth. To fit this number of teeth on a ring gear of a certain dimeter and size, the teeth must be cut at a different pitch (the spacing between different teeth). This then involves changing the height of the teeth and the angle of the faces, and usually the thickness of the ring gear. All these differences mean that the gear teeth on the pinion gears will also have different forms and the "cone" shape of the pinion will also be different to suit the thickness of the ring gear.
As mnemonix said, even gears of identical ratios (and therefore design) need to be carefully lapped to ensure proper mesh and clearance for proper contact and long life, and it's best to keep them as matched sets even when in used condition.

Yeah... Thanks for that... I should have thought of that in regards to the number of teeth on the Ring gear would have a effect on the Pinion ......

rob