MDF cuts|Help needed in getting an estimate

[keith_correa]

For a speaker build - I need precision cut MDF boards and was thinking CNC. I was wondering if I could get a ballpark estimate from someone who knows, on what to expect to pay for getting these cut using a CNC.

One 43"x5" panel with two 3" holes for the woofers and one 2" hole for the tweeter. Internal chamfers for the woofer holes and a rectangular offset for the flushmount tweeter. Roundovers on all 4 external edges.

One 43"x5" panel with a hole for the port and hole for the terminal cup

Two 43"x5.75" panels

Two 5"x3.5" panels

Can someone please help? It would be much appreciated.

 

[asliarun]

I would be interested in the same!

Have you considered using an extra layer of veneer or a sheet of something else with the same thickness as your driver frame thickness to flush mount instead of doing an offset?

Edit: May not work if the drivers have different thickness.

 

[keith_correa]

Extra layers of Veneer will not do. Will need a LOT of layers.
I could use a thin sheet of ply. but then there are problems of bonding et. al. associated with it.
I just need the tweeter to be flush mounted - the woofer frames are thin so no issues surface mounting them. I could use a foam [mouse pad type] pad covering maybe half the baffle - I think the aesthetics will go for a toss though.

 

[asliarun]

Extra layers of Veneer will not do. Will need a LOT of layers.
I could use a thin sheet of ply. but then there are problems of bonding et. al. associated with it.
I just need the tweeter to be flush mounted - the woofer frames are thin so no issues surface mounting them. I could use a foam [mouse pad type] pad covering maybe half the baffle - I think the aesthetics will go for a toss though.

By veneer, I meant the thick-ish variety, usually 2-4mm. I have a couple of drivers which have a 4mm thick frame.

However, your build being a multi-driver one, this may not work.

Out of curiosity, what thickness are you looking at for the front baffle and for the rest of the cabinetry?

Have you also considered using marine ply instead of MDF, or a hybrid approach of the two stuck together with Fevicol or Araldite? I only ask because I too am considering these questions.

 

[jls001]

Googlebaba spewed up this: Cnc Machining Centre in Mumbai - Justdial

 

[jls001]

Also try: Shreeji Waterjet Cutting Services - water cutting, water jet cutting, waterjet cutting, water jet cutting machine, water cutting machine, water cutting machines, water jet cutting machine india Job Shop Navi Mumbai,Pune, Nashik, Goa, Bhivandi, MIDC,

 

[quad]

Check with your local modular furniture manufacturers. The bigger/better
ones should have CNC routers - Durian, for eg.

 

[gobble]

I don't know why people are talking CNC. All this can be done at the local woodworking shop with routers and other tools they have. Holes, curves, rounded edges, chamfers, counterscrew bores, everything. You may need to buy some types of drill bits like forstner bits, cut through hole saw etc., of the right sizes for your requirement. The shops will typically not have all the bits and they will typically say "not possible" until you show them the bits you have. Spending a 100 on a bit exclusively for your project is a tall order for them. Mostly they will have equipment well beyond it's official life cycle whose life they are stretching in typical jugaad style. But its possible to get it done without sophisticated modern machinery. The shop that will do it for you will likely be a jobwork setup where other carpenters bring their wood for fancy curves and cuts. Skip enquiring at the shops that do complete furniture and save yourself some time.

--G

 

[GeorgeO]

The best way to do decoratively is to use solid timber stuck onto the MDFfor the front baffle and mould all the corners too with timber.

 

[santhosh]

I don't know why people are talking CNC. All this can be done at the local woodworking shop with routers and other tools they have. Holes, curves, rounded edges, chamfers, counterscrew bores, everything. .....The shop that will do it for you will likely be a jobwork setup where other carpenters bring their wood for fancy curves and cuts. Skip enquiring at the shops that do complete furniture and save yourself some time.

+1 to Gobble's suggestion. I did exactly that for my DIY subwoofer. I got the mdf sheet transported directly to the woodworking shop near my place and got it cut to size double-baffle, side walls, braces et all. Same chap also did a 11 inch hole on the baffle for the driver using a jigsaw.

Costs:
1 sheet of 8ft x 4ft 19mm MDF - Rs.1700 (Brand: Bajaj)
Cutting costs - Rs.570
Transport - Rs.100
Carpenter - Rs.600 (one day labour charge with a few hours to spare for other woodwork)

Sub is not complete yet, the enclosure is ready...dampening is still pending. I have been wanting to start a thread on my build, but have been busy last few weeks.

 

[santhosh]

The best way to do decoratively is to use solid timber stuck onto the MDFfor the front baffle and mould all the corners too with timber.

George, I like what you have done on your sub. Better still, your MTMs. Guess, you have used pine or is it Americal Ash?

 

[GeorgeO]

Santhosh
I used rosewood(matched panels), and then pine, and I believe white cedar.

 

[keith_correa]

Out of curiosity, what thickness are you looking at for the front baffle and for the rest of the cabinetry?

Have you also considered using marine ply instead of MDF, or a hybrid approach of the two stuck together with Fevicol or Araldite? I only ask because I too am considering these questions.

Am thinking of a 0.75" thickness for the baffle & rest of the cab too

I read somewhere [don't remember where] that the most acoustically dead cabinet is a cabinet sandwich of - any material [say "A"] + a flexible acoustic insulator + another layer of "A" though less thicker that the thickness of the previous layer of "A". Does what I wrote make any sense? If I were to do it this way, I'd use 0.5" ply + a rubber sheet [though I don't know how acoustically dead rubber is] + another sheet of 0.125" ply

Googlebaba spewed up this: Cnc Machining Centre in Mumbai - Justdial

Thanks! I'd already done that. I just wanted a ballpark from someone who knows about this stuff to ensure that I was not getting ripped off.

Guys - the intention of this thread was NOT to find out where to get these cuts done. What I wanted are ballpark prices from your previous experiences if any.
Thanks for all your replies though - they certainly help in some way

 

[t.antony]

From my previous inquiries @ Bangalore, the price starts from Rs.1200 for cutting a 6x3 MDF sheet depending on the "complexity" of work. CAD drawing charges extra.

... I just wanted a ballpark from someone who knows about this stuff to ensure that I was not getting ripped off

It's a concern for me as well... please do post the rates you come across. Try to get a breakup of charges (CAD drawing + cutting charges).

 

[asliarun]

Am thinking of a 0.75" thickness for the baffle & rest of the cab too

I read somewhere [don't remember where] that the most acoustically dead cabinet is a cabinet sandwich of - any material [say "A"] + a flexible acoustic insulator + another layer of "A" though less thicker that the thickness of the previous layer of "A". Does what I wrote make any sense? If I were to do it this way, I'd use 0.5" ply + a rubber sheet [though I don't know how acoustically dead rubber is] + another sheet of 0.125" ply


Thanks! I'd already done that. I just wanted a ballpark from someone who knows about this stuff to ensure that I was not getting ripped off.

Guys - the intention of this thread was NOT to find out where to get these cuts done. What I wanted are ballpark prices from your previous experiences if any.
Thanks for all your replies though - they certainly help in some way

You mean constrained layer damping. I'm trying to understand this technique as well. A good article on this can be found here.

The reason why I said marine ply instead of MDF is because ply is glued and layered, so it should theoretically provide better damping characteristics.

 

[GeorgeO]

Yes, constrained layer damping is the term.

The basic problem with plywood is that all types are not the same.You have por quality and very good quality.Here in India,AFAIK Baltic Birch is not available, but the best variety is what is called BWR-boiling water resistant-one can occasionally get the top grade, known as marine plywood-but this is generally made to order. The difference between these is the glue used is different-phenol or urea formaldehyde, and second one needs excellent dryers to reduce moisture content in the plies, and good presses to ensure that the material is void free

 

[GeorgeO]

Oh I forgot to add that MDF meets most of these requirements and is easily available.

 

[GeorgeO]

On a trip to Hyderabad last week I got a chance to see and audition a diy sub made by a forum member. Criss Cross.Enclosure was about 3 cft(85 lts) made from MDF, a ported design using the Dayton Titanic 12 inch driver and powered by an O Audio plate amp(IIRC).

It rocked!