My new translam Project

[gmed]

Thanks to Keith Kidder, He motivated me to start a translam project of my own. Using a CAD drawing software, I made few sketches and had a local shop cut a few templates using a CNC router. For me to have all the pieces cut using the CNC router, it is gonna cost me a fortune so I have decided to use a template and my home-made router table to laminate all the pieces and cut them one piece at a time. It is very time consuming and one problem I have come accross is that If one layer gets messed up, it is transferred to all the subsequent pieces. So far I have laminated 10 pieces in one day, and Based on my calculations I need around 40 1/2" pieces of Baltic Birch plywood.

I really found a great deal on the wood. I found a place here in LA called Allied Veneer Co. who cut 116 pieces if 18x13" BBB Baltic Birch plywood for $216.

What I have been doing so far is laminate a single layer at a time and cut with the router. I use 5/8" brad nails and glue to hold the wood, then use the router table to cut it using a laminate cutting bit. I may look into having this guy cut all the pieces with his CNC machine, since I am not 100% happy with the results. We will see.

Images not available

[Rene D]

I've been looking at the idea of doing speakers like this for some time now. my main problem was cost of getting all that wood CNC'd. But as a tip for you, Take the two jigs you have now and drill some guide holes, two for the front and say one for the back. you can then glue as many as you like together with some bar claps and a simple 1/2" dowel. just glue up each peice and slide or tap it down the dowel, and so forth. take a framing square and tap it all into place before clamping it all together. and you're done. just be sure to double check with the framing square after clamping.

Rene

[jdybnis]

How much would it cost to get them all CNC'd?

BTW, next time you buy plywood check out Anderson Plywood in Culver City. They sell 5x5 sheets of 3/4" Baltic Birch for <$40. Last time I was there they were selling 4x8 sheets of 13 layer white birch (Chinese) for $35!

[PMazz]

Around here they call that stack lamination. Never heard of translam but it's catchy .

I don't envy you routing all those....

Pete

[yousuredo2]

Looks great, Keep us posted for sure...

I have been concidering this techique for my Modular Mt's...

[gmed]

Considering all the wood cost $216 cut in 18x13 squares, $35 for a 5x5 isnt the greatest deal. Hey, if I had the option of having them cut, I would. Its just not worth paying so much for cutting. This is a DIY project afterall.

Ill keep you guys posted.

[kgveteran]

Great idea. You could even throw in a couple of the template type pieces to add more bracing every fourth one or so.Keep the pics coming.

[gmed]

The fifth picture down is the bracing, which I havent used yet. Im only planing on using 2 braces, each made of 2 0.5" pieces sandwiched together. I really could do without any bracing since this thing is solid as a rock, but Im gonna do bracing, and its gonna look like the 5th picture.

BTW, The guide holes wouldnt add any benefits, they would actually make my job harder, since I would have to cut each level using the template , then glue the, this way I just glue and cut, glue and cut. The guide holes would make it easier if I had them all cut with a CNC router, which Im still gonna look into on tuesday.

[JasonB]

How much would it cost to get them all CNC'd?

BTW, next time you buy plywood check out Anderson Plywood in Culver City. They sell 5x5 sheets of 3/4" Baltic Birch for <$40. Last time I was there they were selling 4x8 sheets of 13 layer white birch (Chinese) for $35!

I'd stay away from the Chinese stuff, it's no where near as good as genuine Baltic Birch.

Jason

[layertone]

Old 1cubic ft BR for fe126e

this seems to be a very popular profile... gmed, what drivers do you plan to use?

(magico's $20k mini: https://web.archive.org/web/20061019...co/mini_2.html)

this unfinished test pair will go to the burn pile... just was not happy with the fe126e / BR enclosure combination - much better & impressive in a horn

Image not available

[gmed]

Very nice layertone. So you hae your own CNC? Are you in the LA area?

If so, we need to talk. ut that is a very nice finish.

G

[layertone]

I'm in North - Sac Area, yes that is my dream toy! :T

That finish, i don't like it - it's PE Adhesive Vinyl....

[jdybnis]

I'd stay away from the Chinese stuff, it's no where near as good as genuine Baltic Birch.

Jason

That's good to know! I didn't try it, but was tempted at that price. In what ways was it deficient?

[bob barkto]

That's good to know! I didn't try it, but was tempted at that price. In what ways was it deficient?

It's not very uniform in any aspect.
The inner plies are lesser quality, varying in color, density and thickness. Also many more voids on average than the "Baltic" varieties.
Panels tend to be less flat and true.

[gmed]

After some calculations, I realized that the first enclosure wasnt gonna work for me, plus it wasnt a good idea to include the notch for the front baffle from the start. The edges tend t get rounded, so Im gonna keep it to the end and place the notch using either my router or a table saw. So I went back to the drawing table and changed some things around. The biggest change was to make the front a little wider so that I could use larger diameter woofers. I initially had intended to use Peerless HDS 6.5", that is one of the reasons I went with a narrow baffle, but I have decided to go with the Scan-Speak 8531G. Here are some of the pictures of the second trial which Im very happy with. It is a slow process but It is great when you actually see the enclosure taking shape.

Images not available

The bottom one is a picture of the wood Im going to use for the front baffle. It is Jatoba which was pretty cheap. It is very dense and heavy.

[gmed]

So far I have only managed to stack up 13" of the speaker, I have 12 more to go. It is difficult when you have to be a resident at the hospital and do this at the same time. I have come accross a problem that maybe someone can help me. Due to the technique that I am using (Stack, glue, cut with router, stack , glue , cut...) the subsequent layers are becoming larger and larger, perhaps due to dulling of the bits and not sanding the layers after each cut. Now that I am upto 13" high, the last layer is about 1/8" thicker from each side. I know how to avoid this now, but how do I make them even now? Sanding may not yield the best results. I was thinking about making a router guide and going all around but that may be difficult. Anyone have any ideas?

I can just ignore it and move on since you cant even tell if youre just looking at it, but it is bothering me.

Any ideas would be appreciated.

[cjd]

Well, you could hit one to two layers in the stack with a flush-trim bit after they're glued in.

C

[gmed]

That is what I use to cut them right now, but since I havent sanded them down after each cut, it has gradually gotten bigger.

[Gir]

Looking good gmed! I'm glad I'm not the one routing those

[h-bar]

Is there a reason not to make a template and then use it to pre-cut each layer before gluing them together to form the cabinet? You could use a couple of alignment holes to ensure registry between layers, and you wouldn't suffer from cumulative effects as you work your way up the cabinet (each layer showing the sum of all the defects in the previous layers). Of course you're the one with hands-on experience, so I could be missing something that should be obvious.

[gmed]

h-bar, youre absolutely right. I should have done it that way from the start. I just thought I may save time by glueing it and cutting it at the same time. Apparently, I never thought of the mistakes, which will be carried on on the subsequent layers. For the next one, I will do it that way. The thing is do I ignore this minor problem now, which is un-noticable unless you are measuring it or do I fix this and if so, how?

[cjd]

It'll be fine as long as both are the same. In other words, don't change your process at all, even for subsequent enclosures.

C

[bossobass]

Interesting project. Sorry to hear of the glitch, it's a big one. 8O

If you glue up the next piece and use a straight bit with a roller guide that rides on the previous piece, they'll all end up the same as the first piece. That way, you'd actually want the next piece to be a touch bigger. I've done something similar aways ago, and IIRC, it worked perfectly.

As you're beyond that now and the pieces are growing toward the top piece, I don't believe there is an easy answer to smoothing them out and keeping the beautifully executed shape intact.

Do I understand correctly that all of the 13 pieces are gradually getting bigger, or does that start at some point along the way?

I would probably try to build a jig that's square from the top piece with a straight edge that's as tall as the piece is so far and use bondo (assuming paint or veneer is the desired end finish?) and run the straight edged jig around the perimeter to smooth the bondo. Much less sanding after that and a better chance of ending up straight and true.

You could then go back to the first suggestion for each successive layer to assure that they'd all be exactly the same from that point on.

Bosso

[gmed]

No, its 13" which corresponds to 26 pieces. It is only off by 1/8", but today I did some sanding with 40 grit sandpaper on an orbital sander and its down to 1/16", the rest Ill do tomorrow. I was just stressing for no reason. The reason it becomes bigger and bigger is that the bit gets dull after about 10 cuts through baltic birch plywood, and also I need to sand the layers after each cut. I have been doing what you describe. I have been using flush trim router bits. That is the only way to do it! If you dont take care of your layers and dont smooth them out, the next layer obvilusly is gonna follow your previous pattern. What you see in the top picture is pretty much how it is, except almost double the heigth. You cant even notice it if youre looking at at. I have already gone through 5 bits! I can still use them but they get dull and its harder to cut with. Thank goodness for Rockler's buy one get one free deal.

[cjd]

Are you using a straight or a spiral cut trim? MLCS has some spiral cut bits that I bet would do *really* well in this application (bearing guided, that is)

C

[Dennis H]

The reason it becomes bigger and bigger is that the bit gets dull after about 10 cuts through baltic birch plywood, and also I need to sand the layers after each cut.

Even with a brand new bit, I'd guess it would grow some. Most flush bits have the bearing just a tiny hair bigger than the cutter, the thinking being you don't want to groove the existing wood and most people will sand the trimmed wood a little. You might want to get a long bit, like 2", and trim 3 layers at a time. That would cut your creep to 1/3 because you'd only be making 1/3 the cuts.

[gmed]

I have to try the spiral cutters next time. I do hear they are better. Cutting through one 1/2" is hard enough, let alone 3 layers. Remember, these bits are not designed to cut baltic birch plywood.

[Dennis H]

I'd use a jigsaw to cut within 1/16" of the line, glue them up, and then use the router to trim the last little bit. That way the router doesn't have to work too hard.

[gmed]

Good idea, I will try that. TY

[gmed]

I need some help. I need some ideas about using a flared port in the back of my enclosure. I know it has an odd shape in the back, and I do have few ideas, but I want to see if you guys have any ideas as well?

What do you guys think of slot port in the back, say 1"x4" with possible flared end?

G

[jbateman]

Even with a brand new bit, I'd guess it would grow some. Most flush bits have the bearing just a tiny hair bigger than the cutter, the thinking being you don't want to groove the existing wood and most people will sand the trimmed wood a little. You might want to get a long bit, like 2", and trim 3 layers at a time. That would cut your creep to 1/3 because you'd only be making 1/3 the cuts.

Or start building the things from the middle, instead of from the bottom. That way each end would only be 1/16" bigger than the center, instead of having the top 1/8" bigger than the bottom.

[jkrutke]

Hello,

Interesting project. You all may see a laminated construction project at Zaph Audio someday. Then again, you may not. We'll see how it turns out. It's obvious a lot of this is inspired by the Magico Mini. Personally, I think stacked plywood is beautiful, but the Magico Mini is flawed by inefficient use of material and less than optimal enclosure design.

I've found a local CNC wood cutter to do it for me relatively cheap.

I've come up with a 2-piece design with the following improvements:

• Better managed internal reflections
• Much more efficient material usage
• Interlocking pieces for easy alignment
• Sexier looks. Yeah, baby!

Most important is the efficient material usage. This will allow "nesting" of pieces to get a lot more out of a single sheet of plywood. Construction of a Magico mini will result in 90% waste of plywood. With better design, the waste can be closer to 50%. With nesting of the pieces, all the parts are cut out of a single sheet on the CNC machine with the pattern properly spaced to make the most of it. This keeps things cheap, as it's all about setup time.

[gmed]

If I may ask, how much are they charging you to cut the pieces? A friend of a friend wanted to charge me $100 per ply sheet. I said the hell with it, Ill cut it myself. One of the main objectives of DIY is to save money!!

[Andy_G]

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[Andy_G]

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[jkrutke]

If I may ask, how much are they charging you to cut the pieces? A friend of a friend wanted to charge me $100 per ply sheet. I said the hell with it, Ill cut it myself. One of the main objectives of DIY is to save money!!

$25/hour, but it's a friend of a friend doing it on his own time on a weekend. I may look into normal business costs, potentially for a higher qty of pieces. Note that I am providing my own material and a tooling path in DXF format ready to be imported and nested. The operator can probably have it cutting within 15 minutes and 100 pieces can be cut out before he finishes his morning coffee.

Keith Kidder's translam project pre-dates the Magico but many years. !!!

Laminated plywood construction has been around for 50 years, it's nothing new and Keith didn't invent it. What inspires about the Magico Mini is it's cost. It's made with brain-dead manufacturing techniques that jack the cost up to ridiculous levels. DIY'ers are inspired that we can do something better for 1/20 the cost.

[gmed]

I was already gonna provide the DXF file which i designed, and the material. I think what this guy was chrging me was rediculous. He is still cutting me the initial patterns, but for me it wasnt worth having him cut all of them. I am already done with the first one. That is the whole fun of it, when you finish and just stare at it!

PS. Does anyone have any port solutions in the back? My choices are flared aluminum tube machined by my uncle, make a flat surface in the back using my router and raised panel bit, then use a regular port kind of like the Sonus faber speakers or a slot port in the back vertically.

[Andy_G]

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[jkrutke]

That's why I didn't understand why you referred to the Magico mini as an inspiration.

Yeah, I guess that's a twisted form of inspiration. It's $20K pricetag inspires me to do something cheaper and better. :B

If my version ever happens, it's more inspired by the B&W 800 series with a deep, tapered closed end enclosure rather than an egg shape.

[gmed]

OK, I can understand why you guys talk about the Magico, but anyone want to comment on my questions!!!

[gmed]

The following pictures explain how Im putting a recess for the front baffle which is gonna be made of hardwood.

Images not available

[gmed]

I just finished most of the first enclosure, and finished glueing the front baffle which is made of Jatoba. After doing that, I noticed that there is a hair line crack that goes to the middle of the baffle is is 90% deep. My options are to leave it alone, to rout the whole baffle out and use another wood, or just rout 1" wide out all the way down and put a contrasting lighter color wood kind of like the pictures below. Any suggestions?
I should have checked more carefully.

[Andy_G]

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[Hank]

jkrutke, please let me know what the 'regular' cnc cost will be. Our CAD guy at work recently built a CNC 4' x 4' table and mounted a plasma cutter to cut metal into decorative plaques, signs, etc. He has fabricated a router holder and is tryinig to figure what to charge me to cut 3/4" MDF cabinet panels with driver holes. He's never routed MDF and is afraid he'll have to program his machine to go really slow in order to cut the MDF without burning bits or flexing the XY rails out of accurate alignment. He thinks the slow speed might make his hourly charge too high to be economical for me. I'm telling him he may be able to run it faster than he thinks, but we'll see.

gmed, chances are, any chunk of hardwood that thick is either going to have a stress crack in it somewhere, or will develop one later. That much wood has internal stresses that sometimes manifest themselves later as cracks after the piece is cut/machined. Mix some 2-part epoxy and force it into the crack (you might mix in some of the Jatoba dust from a bit of sanding).
Keep up the good work - I want to see the results. :T

[moreants]

I was already gonna provide the DXF file which i designed, and the material. I think what this guy was charging me was ridiculous. He is still cutting me the initial patterns, but for me it wasn't worth having him cut all of them. I am already done with the first one. That is the whole fun of it, when you finish and just stare at it!

PS. Does anyone have any port solutions in the back? My choices are flared aluminum tube machined by my uncle, make a flat surface in the back using my router and raised panel bit, then use a regular port kind of like the Sonus faber speakers or a slot port in the back vertically.

I used pvc and flared it into the rear with bondo. (pics)