View Full Version : NEW MEMBER: Evening all

20-11-2014, 11:38 PM
Just signed up, as I just found out in the last week or two CNC kit has come within reach of DIY'ers etc.... Worked in engineering for around 30 years, the last 15 in automotive....use to kit costing 10 or 100's thousands of .... never thought it was so affordable these days.....
That has inspired me to want to build a router/milling set-up.... searching hence landed me here. I'll have few questions to post I'm sure after reading through some of the design threads.
Once made it should be great help in the making of my next Hi-Fi speaker design :)

21-11-2014, 09:34 AM
Look forward to seeing some output, the last speaker cabinets I made were a folded horn design similar to 'Tannoy GRF' in which to house my 15" Monitor Gold speakers.

24-11-2014, 10:00 PM
The front baffle is modelled, offset height, all shaped, looking at curved cabinets which is what lead me to think about a CNC machine !!!
Currently running some design concepts and materials through FEA analysis....... Could be going wood...... well de havilland built the mosquito and Morgan a chassis for years, I figure a CNC machine can't be so difficult :)

24-11-2014, 10:14 PM
Could be going wood...... well de havilland built the mosquito and Morgan a chassis for years, I figure a CNC machine can't be so difficult :)

Both those relied upon or used chassis flex to good extent which we can't and don't need in a CNC machine.!! . . . . . . Stay away from Wood is my advise it's harder than it first appears.!

24-11-2014, 10:26 PM
Exactly, that's the beauty of wood, it's flexible so doesn't snap like a carrot. There seems to be a trend recently with people wanting to make wooden machines, they've probably been looking on US forums.
Personally I don't have the strength to keep saying, "don't do it", so all I'll say is that after building a steel and aluminium machine there is no way a wooden contraption is going to come anywhere near, and I've been working with wood for a long, long time.

24-11-2014, 11:20 PM
Nothing like a challenge :wink:.... To be more exact, 18-25mm Marine Ply, used in "I beam" configurations... maybe with some Aluminium parts in the gantry. The base will be Ply. If I had a cast iron bed plate, hold down clamps and a MIG set yeah I'd make a steel one... but I don't, neither do I want a warped heat distorted frame to shim up and true later.
Aiming at around 1200 x 800 bed size to achieve 1000x600 cutting area. (don't want loose all my garage, as it's only a single!)

Tricky to get some of the stress and modulus data for Ply, anyway current scheme is suggesting via FEA to be 0.02mm deflection with a 50Kg load about the motor mounting platform. (circ 12Kg mass, which I can reduced). Not a bad start I though.
Can't image to see that load on a cutter, but it helps to pin point the week areas. Any idea what the lateral forces are on a cutter?

I'll scheme up an Aluminium gantry with some extrude section 8, 160x80, and end plates to compare, then work out the easiest build sequence. That will required some machining to be contracted out... Some perhaps someone in the Midlands will be able to help out :)

I'll post up a design thread when I've got a bit more data and detailed laid down...... appreciate all the comments, interesting and fun stuff.

25-11-2014, 05:52 AM
Have a look at this product far more stable than wood / ply / mdf, it is quick to cut and assemble, not cheep but you would gain in build time.

Run your design calc's with this product and see results yourself.