Brand new newbie

[Grit monkey]

Hi Jazz,

Thanks for your advice. I've seen quite a lot of threads you've posted on and you sure do help a lot of people, for which I'm sure everyone is very grateful!(how on earth do you find time to get into the workshop? haha.

I will try get a rough drawing knocked up in sketchup and post here on this thread. How soon I do this is entirely dependent on my nearly 2 year old daughter giving daddy time(or not turning off the computer!). I have seen links on threads on here where I can get some plugins for the parts needed which can then be added to the drawing.

I think I would, at some point like to make an entry into machining alloys (think tax disc holder for the bike, just pretty basic stuff really) so I take your point about not being able to throw stuff together and expect excellent tolerances, but I do tend to over engineer anyway. I've done lots of concrete shuttering, so this is where the over engineering comes from.

Anyway, thanks again Jazz, I'm sure I'll be calling on your knowledge at some point in the (hopefully) not too distant future :)

Due to my low paid job, the build will take quite some time, but it would be well worth the wait.

[JAZZCNC]

I've seen quite a lot of threads you've posted on and you sure do help a lot of people, for which I'm sure everyone is very grateful!(how on earth do you find time to get into the workshop? haha.

Ah well that's the beauty of CNC.? . . .Setup. . click cycle start and walk away. Thou it does take a while to get the trust in machine to do that and walk into house.!! . . . . Often thou on an evening I'm sat in my swivel chair in workshop watching it cut while typing these replies.! . . Like Now. . Lol

Crack on and get in-touch when your ready

Dean.

[Grit monkey]

Ok, I've managed to grab a few minutes on sketchup and here is pic of the torsion box.

The method I've used makes for an extremely rigid construction. The top and bottom would be 15mm alu, and the inside of the box would be 10mm alu with the perimeter double skinned to allow plenty for any fastenings.


Ps, the overall size of the box is 1100mm x 700mm x 130mm

[~andy]

What's your calculated weight for this monster base?

[JAZZCNC]

Ok, I've managed to grab a few minutes on sketchup and here is pic of the torsion box.

The method I've used makes for an extremely rigid construction. The top and bottom would be 15mm alu, and the inside of the box would be 10mm alu with the perimeter double skinned to allow plenty for any fastenings.


Ps, the overall size of the box is 1100mm x 700mm x 130mm

Massive OTT really and you could easily get away with half the amount of material and still be plenty strong enough. Your mate won't thank you either having to Weld that lot. . .Lol

Also You say your short of funds do you know how much Aluminium plate costs.? . . . . Even at mate rates that much plate will cost plenty.!

[Grit monkey]

Thank you for the chat Jazz, very informative and certainly lots of food for thought and I think I'll be taking your advice and going with a wood machine.

Anyway, time to get sketching!

[Grit monkey]

I have taken on board the advice given and have drawn another base.
The top is 1100mm x 700mm x 15mm, the sides are 100mm x 10mm as are the braces on the inside. The channel I have left because I'm undecided whether or not to use two steppers for the x-axis or just the one, in all likelihood it will one in the centre
with an upgrade to two when funds allow.
So far the base alone will weigh somewhere iro 50.6 Kg. I haven't yet sourced a stockholder but will ask for recommendations when I'm ready to start buying.

With the base, I will need to think about where to fasten the linear rails, will they be better on the side of the base giving more work area? will they be better on the top for rigidity? Does where I want them to fit have a bearing on the type of linear rail used?

Comments welcome.

[EddyCurrent]

Instead of that I'd be tempted to think about a plywood fire door cut in two.

[JAZZCNC]

I have taken on board the advice given and have drawn another base.

Hi Martin,

Being honest now considering your going to use Aluminium or steel construction materials I think your over complicating this machine with the Torsion box (TB) design.
If using wood then I'd say fine has the Torsion box will compensate for what material lacks in strength but with Ali or steel then you don't have this problem for the level of accuracy required. Only reason I would maybe consider going to to the trouble and expense of TB is if I needed to hold very fine tolerances, and by that I mean really high like 0.0001.

Don't know if your aware of a guy on the forum called Micheal Marino.? But trying to cut very long story short I built Michael a machine from my scrap and scrounged parts from various mates etc. Micheal wanted to contribute but couldn't for distance and other issues reasons won't get into so the only way he could was with design so I mostly left design to him with just bit of guidance from me and between us came up with something that fitted his needs.

Now Sure Michael won't like me saying this but it's true he's Considered one of the best in world for building Custom harmonicas for world class players so the detail and accuracy of his very complex 3D combs his very high. . . . . So to give an idea of what can be archived this machine on a daily basis works to 0.01mm or better in Acrylic and some very very expensive exotic hard woods using Tiny cutters!!

Now the reason Michaels machine can hold these levels of detail is because of design style targeted to his needs just has much has the Strength of materials used along with attention to detail and build quality.

Now having seen (via email) the higher gantry sided design you have in mind then I can tell you the TB won't give you any more accuracy than if building in a conventional manner. The gantry sides will dictate the level not the base.

Now that said for the past 5yrs I have built and refined very similar machine(without TB) for cutting Wood,plastics and Light Ali work made from Profile and Ali plate and can tell you 100% it will do the job no problem with excellent accuracy with good DOC for it's targeted usage SOFTER materials and light ALU work.

BUT If needed to cut Hard materials IE Alu,Brass,copper,mild steel etc to higher accuracy and usable DOC etc then it requires a different design and your TB won't change or add anything of any note other than expense and time to a machine with high gantry sides.!

So if your usage is to cut Soft/hardwood materials to acceptable level of accuracy and DOC etc then go with conventional design and save the money and hassle of building TB. . . . Anything more then forget this design it will under perform.!!

Like Neil says I'd also use Steel to cut down on expense. Can tell you 110% that machine built from steel with Ali bed will do everything you want if designed to your needs and won't cost the earth.