Page 1 of 7
(Yet ANOTHER) DR250 Build Thread!
Posted: Fri May 30, 2014 2:23 pm
by escapemcp
FINALLY managed to get here today:

It's such an achievement for me as they are only open 9-4 M-F.... Which is all the times that I am working (of course!!

). I work in a school, so I am unable to take holidays in term time. It therefore becomes very difficult to get wood . This week is half term and today is payday, so there was only one place I was going today!!
Although I left it until the last minute (actually 5 mins late due to heavy traffic), the yard was very accommodating (they always are). 2 8'x4' sheets of 12mm (½") and 1 8'x4' sheet of 3mm (⅛") bendy ply came to £102. It seems that it is not only neo that is going up in price for these builds

After chopping up the wood, my garage now has more stuff to fill it:
More to follow soon... It's not really the start of the build, but I did cut some ply today, so I'm counting it!!
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Sat May 31, 2014 6:39 am
by Hackomatic
escapemcp wrote: It's not really the start of the build, but I did cut some ply today, so I'm counting it!!
IMO, making sawdust (or PVC wool) always counts! In your first pic . . is that a stack of cardboard or culled pieces of damaged ply?
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Sat May 31, 2014 4:43 pm
by Gregory East
Better to store ply flat on the floor than leaning to, it can get a warp going like that.
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Sun Jun 01, 2014 2:17 pm
by escapemcp
Gregory East wrote:Better to store ply flat on the floor than leaning to, it can get a warp going like that.
Yes, it was only for the photo (runs downstairs and lays wood flat!). The stuff on the left (leaning up against the
just visible generator) is the bendy 1/8" ply... it warps every time I move it!!

The stuff on the right is 1/2" BB.
Hacko - I think it was cardboard. The guy at the woodyard did show me a whole stack of 'black' plywood though (it had been coated, like on flightcases) and offered it to me v. cheap. He just wants it gone from his yard asap. May have to pick up loads and just build cheapy flightcases for everything I own... the only problem is that it is the fittings that cost, but I could build them with minimal fittings (hinges and a catch only).
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Sun Jun 01, 2014 7:40 pm
by escapemcp
Got to make it quick... have to be up in 5 hours
The first piece to be cut (the horn sides I think they are called) has 4 bevelled edges. I have cut the 2 parallel cuts, but then I have to cut the other ones. Is the diagram in the instructions showing the inside of the panel or the outside please? Can't use sketchup, as my computer keeps erroring on install and I haven't got round to sorting it yet.
Thanks. No build pics yet as a single piece of wood isn't very photogenic!
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Sun Jun 01, 2014 11:31 pm
by Tom Smit
escapemcp, I pm'd you.
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Mon Jun 02, 2014 5:02 pm
by Jools4001
escapemcp wrote: It therefore becomes very difficult to get wood!
At your age? They have pills you know...
Looking forward to this build because I've been thinking of some myself...damnit, I've only had the Jacks a few months and I've already got more builds running through my old brain!
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Mon Jun 02, 2014 6:59 pm
by escapemcp
Jools4001 wrote:escapemcp wrote: It therefore becomes very difficult to get wood!
At your age? They have pills you know...
Approaching the big 4-0, so I'm not that young!! (A LOT of people are suprised and think I'm late 20s... I'll take it!)
Jools4001 wrote:Looking forward to this build because I've been thinking of some myself...damnit, I've only had the Jacks a few months and I've already got more builds running through my old brain!
I hope I don't disappoint! I know that feeling you are on about though.

Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 11:42 am
by escapemcp
Still unsure on this first panel cut. I am at work, so have installed sketchup there, but as sketchup seems to round (e.g. ~8"), I have been unable to resolve this. So the instructions are:
The Plans wrote:The leading and trailing edges are cut at a xx degree angle, both facing the same direction
This is fine and I now have a long piece of wood that is x x/xths wide which slants the same way, I can see how that works with the horn no problem. I know I have this bit correct.
The Plans wrote:Keeping in mind the flare of the horn write on them which face is the inside of the horn
Check
The Plans wrote:Cut the other edges at xx degrees, the blade angled so that the inside face is wider
Ok, that makes sense. BUT... then I look at the diagram below this instruction which has the necessary measurements on to make the 2 cuts and then I wonder... is the diagram showing the inside (wider) face, or the outside (thinner) face??
Can someone please explain as I want to make some progress tonight

I did speak with Tom Smit on this, but I don't think I explained myself well enough last time, so I think he answered a different question... I think that he was about to answer my question, but his PM seemed to suddenly stop mid sentence

Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 1:06 pm
by billkatz
escapemcp wrote:Still unsure on this first panel cut. I am at work, so have installed sketchup there, but as sketchup seems to round (e.g. ~8"), I have been unable to resolve this. So the instructions are:
Can someone please explain as I want to make some progress tonight

I did speak with Tom Smit on this, but I don't think I explained myself well enough last time, so I think he answered a different question... I think that he was about to answer my question, but his PM seemed to suddenly stop mid sentence

I just went through this, and there is some ambiguity. However if you look at the sketchup you can see that the 8" dimension on the outside of the horn is not rounded, so the dimensions are for the smaller outside dimension. It is difficult to measure the inside of the horn sides in sketchup, as the horn throat divider gets in the way. Things will look funky when you put the throat top and bottom on, but everything gets trimmed up nicely in the final step.
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 1:36 pm
by escapemcp
billkatz wrote:I just went through this, and there is some ambiguity.
Wahoo! I'm not just being stupid then!
billkatz wrote:However if you look at the sketchup you can see that the 8" dimension on the outside of the horn is not rounded, so the dimensions are for the smaller outside dimension. It is difficult to measure the inside of the horn sides in sketchup, as the horn throat divider gets in the way. Things will look funky when you put the throat top and bottom on, but everything gets trimmed up nicely in the final step.
Back at home now, so no sketchup. When I tried to measure it, I just deleted the rest of the cab panels, leaving only the one I wanted. That way I could easily measure any dimension I wanted to. It sounds like you are actually inside the cab in sketchup... I cannot work out how to do that... as soon as I need to move a bit to get a better view, my centre of rotation is always somewhere totally different and I seem to end up rotating around the tweeter array 3objects to the left
I had convinced myself that the diagram was of the larger sides, as that
tends to be how Bill does it (in my T30 & OT12 plans). Looks like I may have been wrong then. About to go and chop wood now. Damn, the next few pieces are going to be fiddly... someone get the ambulance on standby. I'll make sure I've got plenty of ice to keep any severed digits cool.

Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 4:59 pm
by Grant Bunter
Ok, that makes sense. BUT... then I look at the diagram below this instruction which has the necessary measurements on to make the 2 cuts and then I wonder... is the diagram showing the inside (wider) face, or the outside (thinner) face??
That image simply shows the angles that need to be cut.
It's one dimensional.
When I was building mine, I came to the conclusion that if it was showing the "thinner" face, it would require extra lines showing the angles after cutting as well.
So, in my mind, the image shown is the wider face.
The two 8 degree cuts
will each start from opposite 10 degree sides. ie, one cut starting on one 10 degree side, the second cut starting from the other.
Which way that goes depends on which way your saw blade tilts when setting angles...
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 6:36 pm
by escapemcp
Grant Bunter wrote:That image simply shows the angles that need to be cut.
It's one dimensional.
When I was building mine, I came to the conclusion that if it was showing the "thinner" face, it would require extra lines showing the angles after cutting as well.
If that was the case, then the 13 degree parallel cuts should have the extra line on it.
Grant Bunter wrote:So, in my mind, the image shown is the wider face.
That's how I remember it from the previous build. I think I had the same question on that build as well, but I was able to resolve that time it by reading the plans and working out how it was to be cut.
Grant Bunter wrote:The two 8 degree cuts will each start from opposite 10 degree sides. ie, one cut starting on one 10 degree side, the second cut starting from the other.
Which way that goes depends on which way your saw blade tilts when setting angles...
8 & 10 degrees?? I got different angles to that. Different plan versions??
I made one of the cuts, and then measured it out both ways. The difference is probably 1/16", so I'm going to go with the bigger one and worst case, I'll have to recut it by 1/16".
Sorry for the (dumb/obvious) question, but it isn't made clear in the plans and I know the golden rule... FOLLOW THE PLANS

I just wanted to be sure. It's the first piece and I want to get it bang on - start as you mean to go on and all that!!
Making these cuts with a circular saw is not looking good. Some of those early bits are
tiny. I think I'm going to use a chop saw (or is it a mitre saw - I get confused with all these names). It will require a bit of Sohcahtoa, but it could very well save me a finger or 2
Thanks for everyone's input.
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 6:40 pm
by Grant Bunter
Sorry, yes, 13 and 11
DR200 is 10 and 8.
Same principle though...
Re: (Yet ANOTHER) DR250 Build Thread!
Posted: Tue Jun 03, 2014 11:22 pm
by billkatz
I'm now home where I can go down and measure the horn of my DR - which is just a few steps past that. The outside (smaller side) is 8".