DR250 Build, Perth Australia

[SimonD]

[quote="kekani]
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. . .[/quote]

You may be right, I probably dont need full cleats, just a wedge of timber (probably solid pine instead of ply) shaped to fit the curve of the sheath. Also much less risk of destroying the sheath with solid timber behind it. Basically exacly the same nacelles as in the original drawing but with a reversed curve and mounted inside instead of outside

[SimonD]

I got the second pair of back panels on and trimmed and dressed the first cab. Happy so far, I dont see any voids or holes.



Completed the second HF module, so just the dreaded nacelles to go



Also managed to get the sides for box 1 routed ready for fitting the handles but discovered that I didn't have a patern following router bit, so off the tool shop we go again

You will see from my other post that I have commited to puting the Speakons in the handles.

[Grant Bunter]

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.

I had a similar idea to do this when I get to that build after the prior discussion.

However, since you've done it first, I will now say I'm going to steal your idea

[SimonD]

I marked out the drilling template with where the eight fasteners are going to go. The template is handy because you can get a good idea where there may be issues with allignment etc.
Notice that the holes are not going to be through the braces but next to them. I am still 50/50 on the final solution, but see the next post.



The template is drilled using simple alignment guides clampped to the drill press. There are only two positions that need to be setup, one for the inside holes and one for the outside holes.



The template is clamped onto the HF module for drilling. After each hole is drilled I put a dowel in the hole to ensure that there is no movement at all between the template and HF module.

[SimonD]

I built a litte test piece for drill testing.



And managed to get a very nice hole with a flat bladed auger, so I will probably go with the timber tubes all the way down to the base.
I made a test tube by drilling out the centre of a 5/8" (16mm) dowel in the lathe. You can see it positioned above the second T-nut in the first picture in the previous post. The lathe makes it a really simple job compared to cutting and shaping some more braces.

[kekani]

And I thought I increased degree of difficulty in my DR200 build. Lots of skill in this build. Props for sure!

[SimonD]

I finally built up the courage to attack the dreaded nacelles last night. I've had the HF module clamped onto the drill press ready to go for three days so finally had to pull the trigger.



I found that holding a piece of scrap on the side of the hole where the auger blade had the tendancy to chip the timber was the best way to prevent chipping. I had to very slowly follow the edge of the hole around as I drilled. Fingers are far too close to the blade for comfort



In the end I had no major disasters but nearly ruined the job when I had to re-position the drill base and jig for the second set of holes, but forgot to re-tighten the postion lock on the drill press base
Luckily I spotted the hole going out of alignment early and stopped in time



In the end I wound up with 16 good holes pretty much in position and not too much chipping

[SimonD]

Next up were the timber tubes, these were pretty easy to make but time consuming. I measured the angle of the hole and setup the saw to match



Now just for the record here is an example of how NOT TO DO IT, This is a classic example of a disaster about to happen. This is effectively “pulling” the job through a circular saw and that is the most dangerous thing you can do with a circular saw. The problem is that the saw is trying to pull the material back towards you and when it is at an angle like this, the material moves slightly along the guide which causes it to jam into the blade and the whole process steps up a notch and gets very nasty, very quickly, dragging the job and your hands into the blade in an instant. This is bad enough on a piece of square timber but ten times more likely to happen on a round piece because it only has to roll a fraction for the same effect to be achieved. DON’T DO IT.



This is a much safer option and although the timber rolling is still a concern, it at least throws the job away from the blade.



Drilling the dowels was relatively simple but again time consuming, requiring a pilot hole first then the main hole.



A bit of a cleanup with the sander and they are ready to go.

[SimonD]

I'll glue the tubes in this afternoon. I didn't do it last night as I have to have the cap head screws in position to line up the tubes, and I didn't want to leave them overnight and risk gluing them in permanently

[Bill Fitzmaurice]

Using nacelles is a lot less work.
I considered doing it in a similar fashion, but between the need for tools that most builders don't have, and it being a much more difficult and time consuming process, I didn't.

[SimonD]

I tend to agree with you Bill, just drilling the holes and making the tubes took four hours, and that's not taking into account the setup

Add to it the risk of it all going horribly pear shaped and your solution looks a much better option!

[escapemcp]

I managed to make my holes in the sheath with nothing more than a hand drill. Then used PVC tubes. It initially came out pretty messy, but that gave the hot glue something to fill and bite against. A bit of bondo on top and duratex on top of that, and it looks perfectly ok (IMHO ).



You guys can be far too perfectionist sometimes! Next you'll be telling me I should fully paint the inside of the speaker!

The one bit that has been annoying me though is the white inside of the PVC tubes showing through. I used some spray paint to turn them black, but the screw is such a tight fit that it scrapes the paint off the sides I need to make some little rubber plugs to fill/cover the holes... now that would look better

[escapemcp]

Using nacelles is a lot less work.
I considered doing it in a similar fashion, but between the need for tools that most builders don't have, and it being a much more difficult and time consuming process, I didn't.

I agree Bill, but for me the nacelles were just too obtrusive on the clean lines of the DR. I was happy to spend the extra time to get a nice smooth curve with no nobbly bits!

[escapemcp]

I finally built up the courage to attack the dreaded nacelles last night. I've had the HF module clamped onto the drill press ready to go for three days so finally had to pull the trigger.

I put it off for well over a week before I finally decided to go for it!

[SimonD]

Sorry no progress to report today other than the mounting brackets for the compression horns arrived yesterday and the Dbx DriveRack has arrived at Shipito ready for forwarding. Very happy with the cost, US$146 for the Driverack from American Musical Supply (thanks to 67baja's post) and US$79 for freight & handling, can't complain



Cheers S