re drilling 1850 baffle, help..

Although some say that its not advisable to hold 18's with just clamps...

In particular THAT 18"....... I haven't used the drivers but have you put them on top of each other? if even 2 holes lined up I would be tempted to bolt through those to stop slipping and then use 4 clamps as well for the space inbetween..... that is a hell of a lot of driver to have held with just clamps, if nothing lines up spinning a bit of 12mm ply as an end stop for the rear of the cab so the driver butts up against that would at least stop sliding on 3 of the 4 axis.....

In fairness the pics shown are front loaded so the cut-out (which I bet it pretty bloody acurrate) stops any "slippage" concerns..... But I get your point.....

I only meant use clamps where you can't get in to accurately drill holes to bolt through.  For a heavy driver like that, I would use more than four clamps if I had to do it with them alone.

I am new here and have only just read this post. I know this is an old post, and you have probably sorted this by now, but this info might be useful to others. I had the same problem on some horns a few years back, the answer was key hole surgery. First I made up a cardboard template of the new hole layout. Next get hold of a peice of round wooden broom handle to use as  plugs, so you know what size hole to drill, this is about 25mm, or more. Look through the driver access hole put your template where your new driver is going to go as a guide. You then drill a hole though the top of the cab, use a hole saw, just under the the size of the broom handle, right over the position of your new fixing holes. I done this by eye and it wooked out O/K, but you can measure from the inside of the cab and then mark the outside up before drilling. Once you have access from the top of the cabinet, you can easilly drill your new fixing holes from the top. I had a big chuck on my drill and it would not go though the the 25mm holes I drilled, so I used a long (SHARP) masonary drill to reach the baffle. Once I had made the new holes, I pressed in the new "T" nuts using a mole grip though the speaker cut out, a bit fiddly for the ones nearest the front, (2 of), but the rest were easy. FIT YOUR NEW DRIVER NOW, before you plug the holes, you can fit all the bolts and tighten them easily. Now cover your new driver with a towel and use short pieces of your broom handle to plug the 25mm holes you drilled. Shave them down for a tight fit and use wood glue and tap them in nearly flush with the top of the cab, sand down flush, fill and repaint, job done.