Gauge for measuring bearing preload.

[dawesy]

A little help guys.
I'm currently rebuilding my MR2 transmission and need to set the bearing preload.
It's a max of 3Nm so a normal torque wrench doesn't really have the resolution.
Does any one know of a suitable tool / method for this?
TIA

[BillTodd]

3Nm is not much at all (my torque wrench starts at 5Nm) 

You could use a simple spring balance (e.g. luggage scale) and a spanner of known length

3Nm = 2.2ft/lb   so a 6" spanner would need a force of 4.4lb to give about 3Nm

[dawesy]

Ahhh cool idea. Thinking outside the box?
That sounds like a plan. I did see a torque screwdriver but £40 for one job is a bit much.

[steampunkpete]

3Nm = 2.2ft/lb   so a 6" spanner would need a force of 4.4lb to give about 3Nm

I haven't looked the numbers up, but quick sanity check in my head makes this about right (although the words "sanity" and "my head" do not normally appear in the same sentence).

Luggage scales I think are possibly too inaccurate for your purposes. I would use two 1kg bags of sugar / flour hanging by a length of string myself; I would check them on a set of digital kitchen scales first.

This is probably teaching you to suck eggs, but remember to make sure that the force applied is at right angles to the spanner, e.g. if you are using a weight the spanner must be horizontal. The string holding the weight has to be six inches from the centre of the bolt.

[dawesy]

Well just picked this up from eBay
http://pages.ebay.com/link/?nav=item.view&alt=web&id=181672621827
Worth a punt I thought.