Quote Originally Posted by Jonathan View Post
Agree with what m_c said. You can find the formula he suggested by searching for screw critical speed on google, but assuming the ballscrew is 350mm long the critical speed is 3500rpm - so 3500*5=17.5m/min. The formula isn't that accurate, but that's a huge amount more than you'll ever get on the Z-axis so you're fine to run it. It's <£2 for the bearing you need on eBay, so it's not much loss to get a new one, not that you should have to pay for it anyway.

This thread is the first result on Google for 'Strike CNC', so I wonder how long it will be until they re-brand!

I doubt they will go out of business soon, as it's so easy for these companies to blatantly lie about their products:

http://strikecncrouters.com/page2.htm
Not to worry Jonathan. If you lay too many bad eggs eventually it'll make a stink.

I'm not the only unhappy customer

http://www.cnczone.com/forums/europe...nc_please.html

In particular this comment from that customer rings very true:

"On receiving my machine (the eBay service was great!), I found that the build quality was terrible....really terrible. Basically, I have completely rebuilt the machine, adding a host of parts that I made to strengthen and support the various axes. Most of the extrusions and support rails were not bolted correctly and the stepper motor mounts looked like they'd been chewed instead of machined!

However, I found that the price paid was actually not that bad, when used as a basis for a new machine, but you would most definitely need to at leat check the build quality or better still, strip it down completely."