Media blasting gears

[My68SS]

I note some cluster gears on ebay that have been fully blasted, teeth and all.
I'm not sure that this is a wise thing to do, for a few reasons.
Your thoughts appreciated.

[big iron]

Ron,
You did not describe the type of media used.
I would think that bead- blasting would not hurt the gears but if thourough cleaning was not used, the beads could get into the bearings and cause a disaster.
Bob

[My68SS]

Hi Bob,

Yes, I left the media question open as possible downsides may vary with media.
My main concern was with the disruption to the surface treatment of the teeth leading to premature wear and hence whining, or to even cause the teeth to whine more than they would otherwise.

Also, the possible embedding of particles of media in the surface of the gear leading to premature wear of not just the teeth, but the whole gearbox.
Heavy mineral media like garnet is terribly abrasive, even in it's finest powder form.

Certainly you would want to stay clear of bearing surfaces were needle rollers run.

The reason for asking this is because my nephew is building up a box which needs a cluster gear and also had concerns about the ebay offerings.

btw, Rob - not Ron 

[Stingr69]

Rob,
I just rebuilt my Muncie and used a brand new new cluster gear from Paul at 5speeds.com  My gearbox did not have a lot of miles but the cluster gear was damaged and had to be replaced.  I was concerned about the potential for noise but it did not become noisy after the overhaul.  Why don't you  just buy a new one?  There is way too much work involved in overhauling, installing, and "testing" someone elses used, media blasted, who knows how many eleventy thousand miles, 40+ year old PART to make it worth the risk in my opinion.

-Mark.

[My68SS]

Hi Mark, sorry for my sloooww response [nearly 12 months!!  ]
Not sure what my nephew came up with in the end, I think he found one locally [Australia] of the right ratio and reverse width [saginaw]
It's for a 1st gen GM-H Monaro [Aussie 'Camaro'  ]
I've been reading up on soda blasting and it seems a safe way to go if you want to blast trans parts.