Finding Center distances for surplus Spiral Bevel Gearset

[Archimedes62]

I'm building a prototype using a re-purposed spiral bevel gearset from an angle grinder.
I'd like some advice on the best methods to:
A) determine the center distances
B) estimate the torque capacity

No, I don't have the original angle grinder that the gearset was designed for, and specs from the manufacturer are not available.
I don't really want to go through a full reverse engineering or digitizing to determine the PD, tooth form, etc. At this stage I want only to design and build a quick but durable proof of concept prototype.

To find the center distance I've considered making an adjustable bearing block (3D Printed) and then running it at a range of speeds under no load to experimentally determine the center distance that seems smoothest / quietest.

Is there a rule of thumb for engagement / offset between gears from their fully contacted meshed position

Suggestions?

 

[gearcutter]

Ensure that you know the mounting angle at which the set was designed to mesh at, eg 90 degrees.
Also make sure that the mounting distance that you chose allows for backlash and a contact mark that favours the toe (when not under load).

You would need to reverse engineer the set to determine the load capacity.
Having said that; go to a hardware store and look at all the similar gearboxes there. Chose the one that closely resembles yours. Look at the tool's speed and power ratings.
That should give you a very, very rough idea.

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[Archimedes62]

Thanks Ron - very helpful!