DR250 Build, Perth Australia

[kekani]

Wait, just realized, doesn't this mean the end angles are the wrong way as well?

[SimonD]

Wait, just realized, doesn't this mean the end angles are the wrong way as well?

I'ts only the angle that is the wrong way, but as I said, I can slice off about half an inch of the angled edge at 90deg, turn it over , and glue it back on the right way round.

[Grant Bunter]

Enjoying your build and your honesty!

Keep up the good work...

[SimonD]

Not a lot of progress this week as I have been getting my rehearsal space sorted out.
I managed to get the sheaths on and sealed.

[SimonD]

Got the first of the side braces on





Trimmed and cleaned up the overhang on the sheaths.



I also got a coat of primer undercoat on the inside surfaces that are about to be hidden forever

[SimonD]

Hi Folks, Good progress this weekend
I'll start with fixing the little mistake on the HF module where I glued the flange faces on upside down so that the angle was the wrong way round. I simply cut the edges off with a circular saw.



And glued them back on the right way round



I fabricated the compression module horn assemblies



And fitted them to the flanges





Notice that I left a ¼’ gap at the ends where I will put a little cover plate to seal the module as per an earlier discussion.

[SimonD]

After another little error where I aligned the centre brace with the middle of the front of the cab instead of maintaining the offset, I removed the brace and (with minimal damage to the surrounding timber) and glued it back in the right position.



I then trimmed and fitted the remaining side braces



And after masking the edges got a couple of coats of undercoat sprayed on.



I am pretty happy with the finish that I'm getting with the spray gun and I find it much more satisfying than painting with a brush, which I absolutely hate

[SimonD]

HF modules are looking good with a test fit showing no issues.



I picked up some decent speaker wire today so I now have all the components other than the Duratex.
I am still not 100% on the colour scheme but I think I might go for red horn faces with black bracing.

[AntonZ]

I was able to fit the T-nuts. I recessed the woofer spacer with a 7/8 flat blade boring bit.



Fitted the T-Nuts



And mounted the spacers (after confirming that I could actually get the drivers in when the side covers will be fitted )

It took me a while to see, but I would think there is not that much "meat" left between your T-nuts and the driver, once installed. Tighten them real fast, and you risk pulling the T-nuts through the spacer. I would rather have had the T-nut on the other side, yet another 1/2" further away from the driver, if you know what I mean. I'm not a native english speaker, so searching a bit for understandable wording here. Not sure about wording, and about my point. Others may chime in.

Other than that, great build thread, lots of pictures, always good.

[SimonD]

Hi Anton, the T-nuts are only recessed 1mm into the back of the spacer. That leaves 11.7 mm of "meat". That is plenty! I don't intend to over-tighten them and I will put a lock washer on the cap-head screws. It would take an enormous amount of force to pull a 20mm T-nut through the timber and I hope I'm not that "ham-fisted"
I take your point of going through both pieces of timber though. I could still do that if I run a drill and tap through the centre of the T-nut and put a lock nut on the back.
Cheers S

[SimonD]

Somewhere under all those clamps is a HF module with the first sheath being glued on to it. I think I'll make a jig to glue the others

[SimonD]

Happy to report lots of progress this weekend

I fitted the custom cover plates on the end of the HF modules. A fairly simple task of tracing the outline directly from the module and cutting it our with the band saw.





and glueing them in.





Next came the driver mounts that I cut out with a couple of hole saws. First the centre hole



Then the outside



And stuck them on



Also got the flange brackets and dowel installed (I left the dowels un-glued untill I have painted the modules)

[SimonD]

After two coats of undercoat/primer, the cabs got their first coat of black.



and the first of the back halves went on. I have had them pre-bent for a few weeks so didn't have any dramas with cracking or splitting. I didn't bother with nails or anything as I was able to get them fitted nicely with the tie-downs and clamps.

[SimonD]

With regards the dreaded nacelles, I have started making a template to drill the mounting holes. The plan at this stage is to make some timber tubes by drilling out the centre of pieces 5/8 (16mm) dowel. I will drill a hole in the module sheaths and mount the timber tubes through the sheaths down to the flanges but not through the cleats. I will use 8 x ¼ Cap head screws and T-nuts for each module.



It's pretty scary doing anything to the modules at this point as they take sooooo much work to get to this stage and I don't know if I could deal with a disaster. Drilling the holes in the sheaths is the really scary part as it can all go very wrong in a very short time.
The plan is to first drill the 1/4 holes in the flanges with the template. Then make a simple jig by attaching a piece of board to the drill press, big enough for the module to be moved around under the chuck. I will drill a 1/4 hole in the centre of the board and put a little 1/4 dowel in the hole. Then, without moving the drill press base, the module can then be perfectly aligned for each hole under the chuck using the 1/4 dowel stuck into the pre-drilled holes in the flanges. That's the plan anyway, any other suggestions would be gladly accepted!

[kekani]

With regards the dreaded nacelles, I have started making a template to drill the mounting holes. The plan at this stage is to make some timber tubes by drilling out the centre of pieces 5/8 (16mm) dowel. I will drill a hole in the module sheaths and mount the timber tubes through the sheaths down to the flanges but not through the cleats. I will use 8 x ¼ Cap head screws and T-nuts for each module.

It's pretty scary doing anything to the modules at this point as they take sooooo much work to get to this stage and I don't know if I could deal with a disaster. Drilling the holes in the sheaths is the really scary part as it can all go very wrong in a very short time.
The plan is to first drill the 1/4 holes in the flanges with the template. Then make a simple jig by attaching a piece of board to the drill press, big enough for the module to be moved around under the chuck. I will drill a 1/4 hole in the centre of the board and put a little 1/4 dowel in the hole. Then, without moving the drill press base, the module can then be perfectly aligned for each hole under the chuck using the 1/4 dowel stuck into the pre-drilled holes in the flanges. That's the plan anyway, any other suggestions would be gladly accepted!

You know, I saw Grant do something similar with the "tubes". I didn't get it, until I needed to. My laziness got the better of me and that's why I made the cleats out of 3/4" ply. Forstner bit through them and you have just drilled your "tube".

In your situation, I wouldn't even make full size cleats - just enough for the drill to make a "tube". Cut 16 pieces, glue, drill, done.

Although, Grant's PVC came out clean.

Of course, look who's talking - the guy that did the thread on how "not" to do it. . .