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View Full Version : Making a set of 120Ti grilles



vettedrummer
08-17-2007, 06:43 PM
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
08-17-2007, 09:20 PM
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
08-18-2007, 12:22 AM
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.

27430

macaroonie
08-18-2007, 03:53 AM
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
08-18-2007, 04:14 AM
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
08-18-2007, 05:25 AM
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
08-18-2007, 09:30 AM
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
08-18-2007, 11:51 AM
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
08-18-2007, 11:59 AM
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
08-18-2007, 12:20 PM
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
08-18-2007, 12:35 PM
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 :)

27452

Storm
08-18-2007, 12:36 PM
Why on earth are they in the attic, may I ask?

;)

-Storm.

Andyoz
08-18-2007, 12:40 PM
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!!)

27453

macaroonie
08-18-2007, 01:17 PM
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
08-18-2007, 01:59 PM
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

SEAWOLF97
08-18-2007, 02:01 PM
unless you have woodworking tools , the 2 chamfered edges may be a problem..

my biggest challenge is the grill cloth at the corners...anybody got a good looking method for the corners ?

Andyoz
08-18-2007, 02:14 PM
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.

Hmmm, it does look like there are two, but I only remember there being one???

Evets
08-18-2007, 06:11 PM
"I'm nearly 100% sure there is a middle piece..."
That just shows how bad my guesses are :).


"PM me your email guys and I'll send the hi-res photos that may help."
Thank you for the kind offer. PM will be sent.


"unless you have woodworking tools , the 2 chamfered edges may be a problem.."
Fortunately, I have plenty of tools, including a router table and a variety of round over bits. Alternatively, I can buy quarter round stock at the local lumber yard.


"my biggest challenge is the grill cloth at the corners...anybody got a good looking method for the corners ?"
I still have to figure this out, but I think that a couple of tricks I learned building wooden screen doors will apply to these small scale screen doors.


Thank you all for the advice and help. I will try to settle on a construction method that lends itself to pseudo mass production.

-Steve

vettedrummer
08-18-2007, 06:17 PM
I like the photo's of the router doing it's thing. I have a brand new one still in the box. I guess this will be the time to get to know it. Looks pretty straight forward really. to be honest I never thought of a router cutting a hole like that one. I thought of using it to make fancy edges and stuff like that, but this has really opened up my eyes as to what it can really do. I'll have to take it out and play with it a bit to see just how it works. I have lots of other power tools, but never have done something like this before. So the guide on the router just runs along the outline of the template and the cutting part repeats exactly what it's following. Very neat! I'm going to like this project. It is clear that I will need a way to place those peg holes. Perhaps using the speaker cabinet as the template for those hole since I don't have the original grille to use as a pattern. I understand the outside measurement of the grille is 22 and 3/8 by 14 and 1/4. I do not know how wide the actual frame is however and the thickness of the factory model may be a little thinner than what this one will end up. I plan to make it the same thickness as my 240Ti grill so it will be a little stronger than what the plastic one is on the factory 120Ti. Hope this doesn't upset anyone, but if you've got nothing to compare it to it will look right! I normally just work with veneer over old work, but i have built cabinets before, but never this accurate! I think this I can do. Looks like once you get that first pattern done you should be able to crank them out. Now the grille cloth over the corners so it looks like theirs, I think I read one time that if you pull it just right and use a little heat it does what you want it to. That part can be played with until you come up with the method. Too bad I'm working this weekend so I won't get a chance to try working on this till maybe Monday afternoon or Tuesday. 12 hour midnight shifts really messes you up and your desire to do anything. I don't think my 120Ti cabinets will reach my home till late into this week anyway. Cheers, Frank

oldsoundz
08-18-2007, 06:27 PM
Let me know if I can be of additional help. Looks like plastic, but the crossbar looks like wood.

vettedrummer
08-18-2007, 06:31 PM
In the photo with the router running on the template over the new work. Is the template attached to the new work in some way and if so how was this done? Is the little gray area on the left in the photo the point where the old grill is broken? Looking more at the photo's of the real 120Ti grilles it appears that the top and bottom cross points top and bottom and center too I guess are much thinner then the up and down rails, true? This might have to change to make it stronger. I'd hate to see just pulling the grille cloth tight breaking the wood! It's a little slow at the hospital tonight so I have time to think about this alot. Cheers, Frank

vettedrummer
08-18-2007, 06:35 PM
WOW, it is all very thin plastic on those outside edges. This really has to be made thicker don't you agree? I was going by the way my 240Ti's look, but this would never work in wood as thin as they have it. Does anyone think they could make it this thin and make it not break when you pull the grille?

Evets
08-18-2007, 06:44 PM
Those a great pictures, Oldsoundz. Thanks for the help. Any chance you would be willing to take some measurements? For that matter, if you a take a closeup of a ruler laying across one of the corners I should be able to get most of the measurements, excluding the thickness of the frame perimeter and the width of the cross brace. Thanks again.

-Steve

I almost forgot, if you're willing to take some measurements I would also appreciate the distance from the face of the speaker to the back of the frame.

oldsoundz
08-18-2007, 07:05 PM
On my way out the door right now. Will get on it when I return.:D

oldsoundz
08-18-2007, 10:40 PM
As requested. Please let me know if there are further questions I can answer.

The outer part of the framework is 2 piece. It looks like the cloth wraps around
the outer, then is held in place by the inner, which is notched in the center for
the crossbar.

macaroonie
08-19-2007, 04:21 AM
I'll wager that if you have a rummage around you willl find a pan head screw where the head will locate in the grille peg socket on the cabinet.
If that is the case you have your pegs.

macaroonie
08-21-2007, 03:57 PM
The taped up bit is the break.
Yes the roller guides exactly to the template. It is a good idea to cut to within 1/8" either with a jiggy or hand saw for the straight edges. Whilst the router will cut its own path width it is rather hard going and throws out a lot of waste.
The other issue I had with these was making sure that the long thin edge stayed true to the template. If you think about it every turn that the cutter makes delivers two whacks to the workpiece. A panel pin partially driven through will stop deformation.
Screws in the corners hold everything in place.

WATCH THE FINGERS !!!

vettedrummer
08-21-2007, 06:37 PM
Hey Macaroonie, thanks alot for the photo essay on routing 101. Those photo's are very informative. Now If I had one grille to follow like that I'd be all set. I'll have to make up something to run the router along in order to keep it straight, but that shouldn't be hard to do. Thanks again! Cheers, Frank

Evets
08-22-2007, 01:12 PM
Thanks Oldsoundz, for the new set of picks; they are quite helpful. I would have thanked you sooner but my modem crapped out and I had to replace it. Anyway, I will try to build some prototypes this weekend and I'll report back with my results. When I finally decide on a particular manufacturing process I'll either post some pics here or start a new "build" thread. Thanks again to everyone for the advice.

OK Frank, now it's time to see when we can get enough time away from work and other obligations to build the grilles. Good luck.

-Steve

opimax
08-26-2007, 05:48 AM
Still following this thread...I would be happy to ship one of grills if that would help.

Mark

Evets
08-26-2007, 09:38 PM
Although I didn't make the grilles this weekend as I had an unexpected day of car repair eat up my free time, I assure you I will complete this project. Rather than ship your grille, however, I might wind up sending you a swatch or two or three of speaker cloth in order to match the original color. Would that be acceptable to you at some point in the future? I will most likely make two pair: one with black speaker cloth and one with as close to the original color speaker cloth as I can get.

-Steve

macaroonie
08-27-2007, 08:05 AM
Here is finished item.

vettedrummer
08-27-2007, 03:51 PM
Opimax, thanks, but grilles are not needed. I'm building it to match the 240Ti grille! It will look like the 120Ti, but it will be a little thicker. The crossbar will also be a little thicker. I have a bit of brown cloth from the Decade L-36 that I will use for this first model. The cloth is a bit more open and substantial then the double knit used on the Ti series. Still looking for a good replacement! Cheers, Frank

vettedrummer
08-30-2007, 02:26 PM
Hey, I got bad cabinets from Stereojack see thread in tech help. Grille making on hold till I figure out a way to fix cabinets. These were not damaged in shipping (YEAAAAA UPS), but by water while jack had them or whoever he got them from! Big problems!