isotropic finishing with tumbler, how to

[samtgallagher]

anyone have info on how to do an isotropic finish on gears or other small parts?

I seen a few articles online but can't get any substance out of them, as of the process and what is needed.

thanks

[samtgallagher]

40 views, no replies? surely some of the more experienced guys on here has some info on it

[CarWiz]

anyone have info on how to do an isotropic finish on gears or other small parts?

I seen a few articles online but can't get any substance out of them, as of the process and what is needed.

thanks

Personally, I think it's a crock but it seems to be supported by "engineering" data. All it means is the gear or whatever is surface finished with a random pattern instead of ground, etched or plated. It involves tumbling the item in media along with proprietary chemicals. The word proprietary is probably why you can't find much info on the process. But.... if you dig hard enough, the methods and processes are documented in detail.

I doubt that anyone on this forum is using the process but I could be wrong. The process can be expensive and as I noted, seems more myth than fact.

[CarWiz]

Here's a snippet of one article about the process.

"Vibratory bowls are commonly used in metal finishing for genetic deburring. But by using nonabrasive, high-density media in conjunction with an isotropic superfinishing chemistry, vibratory bowl finishing can be used to superfinish the surfaces of complementary components to an isotropic (random) finish. This improved surface increases energy/motion transfer efficiency in the metal-to-metal contact area by reducing friction and providing an additional number of engineering advantages."

It may be beneficial to NASA but I fail to see an advantage over lapped gear faces.

[samtgallagher]

It may be beneficial to NASA but I fail to see an advantage over lapped gear faces.

actually it is very beneficial to people that are pushing the mechanical limits of their equipment.for two gears to be able to run against each other with not even less resistance, just smooth resistance would result in less chance of damage. running motorcycles at 80hp+ per cylinder is pretty extreme.

[CarWiz]

That may be true if you are running the gears dry but no amount of micro finishing is going to project above an oil film. The finish could cause turbulence or resistance in the oil film thus causing drag. That's why they still polish crank journals. The pressure point (pitch diameter) between two gears is very small and it moves in shear. Unless your gears are made of diamond, no micro finish will stay for very long. But hey, give it try. It's only money.

80hp/cyl is no big deal unless the piston is the size of a Pecan. Big horsepower happens a lot around here.

Ken

[samtgallagher]

That may be true if you are running the gears dry but no amount of micro finishing is going to project above an oil film. The finish could cause turbulence or resistance in the oil film thus causing drag. That's why they still polish crank journals. The pressure point (pitch diameter) between two gears is very small and it moves in shear. Unless your gears are made of diamond, no micro finish will stay for very long. But hey, give it try. It's only money.

80hp/cyl is no big deal unless the piston is the size of a Pecan. Big horsepower happens a lot around here.

Ken

i don't think you understand the process by making that first statement. this finishing replaces gear lapping, which is an extremely long process and a PITA.

and 80hp per cylinder on a motorcycle is a big deal. we're working with under 1000cc motors here. I know it's easy to make big power with a little bit of displacement. my 7mgte block here is 3L and it seen 648whp last year, I just got it refreshed and plan on spraying it this season, so we should be in the neighborhood of 725-750whp on 24psi so i'm not a complete dumby when it comes to making decent power with a car engine either.

actually just got the block back yesterday