Making a set of 120Ti grilles

[vettedrummer]

Hello all the woodworkers out there. Ok my next job is to make a set of grilles for the 120 Ti's that I just got from ebay. (Once done I will have the whole Ti family) These are empty cabinets which may need a little fixing, but I can handle that. Making grilles, ones that won't warp or look any thing less than factory is what I'm after here. What kind of wood should I use? How should I go about it? I know the size they need to be and I figure that they must end up looking like my 240Ti grilles. So I know how thick to make them and how they should look, but what did JBL use for the wood? Was it cut from a piece of MDF??? Was it sticks? Let me know what you think. Or if anyone would like to build a set of these for a fee I'm open to that too. Ok what say you???? Cheers, Frank

[Evets]

I have the same project ahead of me, but unlike you, I do not know the exact dimensions of the originals. I do know that he 120Ti grille frames were plastic whereas the larger Ti grille frames were MDF (according to what I've read elsewhere in these forums). I plan on making MDF frames as that is as close to original as I'm going to get, but I haven't abandoned the idea of using hardwood. I'll be happy to return here and share my building experiences if you haven't already completed your project by that time. Good luck.

-Steve

Edit: I was just looking at some other grille build threads and based on them you might want o consider solid pine or a wood equivalent. Check out the "Making L300 Speaker Grilles" for some opinions on frame material choice.

[Andyoz]

Guys,

My set of 120Ti's are boxed up in the attic. If you get really stuck, I can take one down and measure/photo the grilles.

Yes, they are plastic and very thin profile. I recall they have a nice bevelled outer edge running down both sides. They really are a nicely designed piece and add to the look of the speakers a great deal. Anything you do with wood will be a compromise as I can't see that having the stenght to get the ultra thin profile of the originals. Best I can do ATM is a cropped version of a photo taken before I boxed them up.

[macaroonie]

I dont think I would use MDF since as I remember the stock item is really quite thin in the area of the bass driver. Mdf would probably not have the strength over time.
I would suggest 3/8 baltic birch. In the thinner sizes the plywood people reduce the veneer thickness so you still have several laminations.
Nice to work with and good and strong.
You will need to hunt down the pegs which stand off the grille from the baffle.
Andy will tell you by how much.

[Andyoz]

You will need to hunt down the pegs which stand off the grille from the baffle.
Andy will tell you by how much.

They stand off quite a lot, more than the photo above indicates that's for sure.

[opimax]

I could ship you 1 to work with, and then let me purchase a few finished products. I have 6 120 and need about 4-5 grills

Is the exact brown cloth available? so they match the rest of the TIs.

Mark

[Evets]

Hi Frank,
As mentioned above, I have the same project in mind; however, I don't want to hijack your thread anymore than I already have without your permission. Is it OK with you if I join in the process and ask questions as well, or would you rather I start my own 120Ti grille thread?

-Steve

[vettedrummer]

Steve, no problem! Just keep it only about 120Ti grilles. I like the Baltic Birch idea. The other way I thought of was to use some kind of hard wood and do it as a picture frame type assembly. I just couldn't figure out how to make the corners strong enough.
Now then does the 120Ti grille have a center horizontal middle bar in them? ( The 240Ti does) Are the corners in the shape of a pyramid to mount the pegs in? Why can't the pegs be made of wood? Since they don't show and it could be made to fit in the existing cabinet holes. Only problem I see right now is the placement of the pegs to be sure they line up with the cabinet holes. Some kind of template is needed here. Perhaps something that would fit over each corner to show just where to drill. I guess that is where having one real one would make that part go well. Brown grille cloth???? I know a place in Fla. that I have used before I'll order a piece and see if it matches up. Were all the grilles on the Ti series BROWN??? They didn't make any other color? If this goes well I think I'd like to make up two sets for me one in brown to match the other ones I've got and then one in another color for fun and so it fits into our color palate better. Could be torch red, light gray, black, or white. That would cover it. If it goes well Opti sure I can make more perhaps just the frames and then you cover to taste or perhaps the whole thing if the brown matches. OK, enough of my ideas what does the forum think??? Cheers, Frank

[vettedrummer]

Hey, another point are the left and right edges totally rounded or is it a quarter round? The ones on my 240Ti's are totally rounded with flat tops and bottoms. Other than the 250Ti's in the piano gloss black did JBL make any of the other Ti speaker in black? I know they did clear Oak cause I've seen those for sale when they were new. Perhaps walnut as well I know the older L250 came that way.

[Evets]

Thanks, Frank. I'll play too and I'll keep it focused on the 120Ti.

If I were to make the frame out of baltic birch or MDF I would make a template and use a router to create a single piece frame to which I would attach a two piece wooden peg assembly.

If I were to construct the frame out of hardwood (the more likely choice at this point given the recommendations of other forum members) I'm not certain of the procedure I would use, but I would likely start with a four piece frame joined with mortises and tenons. I believe I saw a picture once upon a time of triangular bracing in the corners of a 120Ti grille frame and I would replicate that element with an appropriate material glued into dadoes in the corners of the frame. I doubt the 120Ti grille has a cross member in the middle given it's size, but I 'm just guessing here.

As far as the peg holes lining up, I'll simply construct a drilling template based on the mounting holes in me grille-gree 120Tis. No problem there.

Matching the brown speaker cloth is a bridge I'll cross when I get there unless someone else already as the answer. I'll do a forum search later to see what I turn up.

Although I can get very close to the original dimensions based on the picture supplied by Andy and the other pictures I bookmarked, what I really need at this point are measurements from someone who has a grille. Pictures of the rear of the grille would be nice as well in order to show me the glue/attachment method used by JBL. Rather than shipping a grille to me, I think a photo or two and some measurements would suffice and save unnecessary shipping. Surely we can get the measurements without asking taking Andy up on his offer to unpack his secret stash in the attic, although I certainly appreciate the offer.

Although I will make a pair of grilles for myself I do not want to commit in any way to making grilles for anyone else simply because these will be my first speaker grilles and I don't want to make a promise I may not be able to keep. That said, I do have a decent wood shop and more than a little experience building things out of wood. If I prove capable of making a decent pair of grilles without too much trouble, I would be more than happy to duplicate my efforts for Frank and Opimax (and other members?). Another thing on this point that I should mention is that I have two small children and several other projects ongoing so I may or may not get this built right away. It is possible I wouldn't finish them until sometime in September.

-Steve

P.S. Frank, I'm fairly certain from looking at Andy's picture that only the sides a rounded over.

[Andyoz]

I'm nearly 100% sure there is a middle piece...it's just visible as a shadow in this shotI think.

PM me your email guys and I'll send the hi-res photos that may help. As I said, if they weren't boxed-up in the attic, I'd have better photos posted already

[Storm]

Why on earth are they in the attic, may I ask?



-Storm.

[Andyoz]

Actually, the middle bar shows up better in this shot without the flash. The bar is actualy in the line of the woofer so they must have just placed it at the geometric centre of the grille for max strength. Also, these photos make the grille frame appear much thicker than it actually is...I mean thickness from the baffle out, not the other way.

YES, Storm, looking at these I'm going to have to find space in the house to fire these up again. They really are a great package. Bought them with 100% re-cones to both woofs and mids and have only listened to them for less than 30mins (long story!!)

[macaroonie]

I had a close look at the above picture and have ' roughly ' marked out the areas of interest. It looks as if there are two cross spars and you can see that the frame overlaps the bottom edge of the bass driver.
I would still go the birch ply route.
If you were to try to make a stick frame have it jointed with a picture framers underpinner ( go have a wee look at the back of any pic frame ) and then add in the necessary fillets in the corners.
If you go with the ply you should aim to make a routing template in order that you can make many. Not hard to do at all

[macaroonie]

Have a look at this broken 4312 grille frame. Temporary repair allows roller guided cutter to copy exactly the original shape as many times as I like.
All you have to do is plan out a shape and make one only then do this for repeats. It does the outside cut also ie the excess outside the frame.
The internal was roughly cut out with a jig saw. Once you are done cutting the basic shape you can round over the side edges and then drill all the little holes for pegs etc