I'm wanting to improve the sound isolation in my car, specifically wheel wells and door cars, possibly fire wall and floor. Are there any recommendations for places that can help with the installation Cape Town/SWest side?
I'm putting together a project that would include a 6mm (just under 1/4") hot rolled steel fixture table made up in part of a grid of 60 x M8 tapped holes. Tap drill size for this would be 6.8 mm (just over 1/4").
Laser cutting is the go to local solution. I dont want want to tap into the heat affected zone, so would want to undersize the holes to drill clean and tap. I would like to make the most of the precision afforded with laser cutting, so would want to at least get a pilot hole cut.
Conventional wisdom is pilot hole with the smalled size bigger than the spade of the final size drill. Do you think I would be better suited to pilot with something like a 3mm hole, or something near final size like a 6mm?
Any advice for drilling and tapping 60 holes? Mag dril is probably best, but seems overkill for 6mm thick plate?