Just FYI, all antennas close to metal tune differently, parallel conductors can be capacitors and alternatively passive elements. What you've done is going to probably shorting your antenna from an RF standpoint.
Have you checked your antenna with that? My guess is it's gonna see a big, fat reflection and very high SWR.
Originally Posted by MDH33
Yes, normal i-bolt with a fender washer and nut, inside and out. Here's a pic: <photo snipped>