Chipper blade nut torque change if zinc plated?

[mrrly]

The manual for our 2nd gen. Bandit 65 chipper says blade bolt nut to be torqued to 80 foot-pounds. The grade 8 1/2 x 13 USA-made nyloc type lock nuts I have have a yellow zinc coating. I've read the torque for zince plated nuts is different that for plain steel nuts. Should I use a different torque value? Thanks.

 

[flushcut]

I hadn’t heard that. Does the torque value go up or down with zinc? I know dry torque values are much higher than lubed values to achieve the same clamping pressure. Or just get the same nut as factory and not worry about it.

 

[Cobleskill]

Google Search

It looks like slightly more torque is needed for zinc plated.

 

[mrrly]

A little more torque is what the best chart I've found so far says. But most charts just refer to plated components as if both the bolt and nut were plated, whereas many circumstances, like mine, are with a plain bolt and plated nut. Maybe I'll go 90 ft-lb at most. Factory bolts are quite expensive. Bolts should be changed out every 5 blade changes , but I don't know if that includes changing the nuts.

 

[SeanKroll]

The dealer will know best.

There might be a manual available through the dealer.

Vermeer has free online manuals for their products. Maybe BB, too.

 

[mrrly]

The manual says 70-80 for authorized hardware, which I believe is plain steel. Just their special (proprietary?) nuts are $6 each x 6 for every hardware change. They don't get into hardware specs for anything other than what they sell.

 

[mrrly]

Well, I just read that zinc plating acts slightly as a lubricant, so that would mean I would not tighten the nuts as much as bare steel ones. I'll figure this out. Fortunately, I think whatever adjustments need to be made are not great.

 

[flushcut]

What’s the diameter of the bolt? I have a feeling if you torqued to 80flbs you’ll probably be fine.

 

[mrrly]

1/2 in x 13 grade 8 for both the plain steel bolt and zinc plated nylock nut.