BuildingAfloat

[BikerAfloat]

Hi Jazz,

I see some issues that will definitely affect it's ability to cut steel and will also affect performance in Aluminium.?

I am really not surprised by this :-) , it is why I have sought help on the design! I am starting to think that some of the videos of what to me at least look like flimsier machines cutting Ally accurately, might be using a bit of artistic licence!

The tall gantry won't be any where near strong enough.!! While it's sat directly on the bearings the what looks like 45x45 uprights just won't handle the forces steel and aluminium will put on it.

Although doubled up, the uprights are in fact just 40x20! so are as weak as soft smelly stuff in that case :-) I was thinking of joining the two Y Axis cross beams with a sheet of Ally to stiffen the entire structure, just haven't got round to adding it to the drawing.

The un-supported rails on the Z axis and to be honest the whole z axis design just won't be upto the job of steel or Ali.!

Don't know if your planning on putting any braces across the frame to support the bed.? But again to cut any hard material then extra support will be required.

To cover both of the above points, the Y Axis will travel over the cross members at the front of the X Axis and I was planning to work the material with the Z Axis as close to the top of its travel as possible. That means all loads will travel the miniumum distance to the strongest parts of the machine. Not sure if that will help enough? I am hoping to keep the centre as free from bracing as possible as I want to be able to engrave on Motorcycle engine cases, but I guess it is only a small amount more work to remove bracing to get big stuff up from underneath, when compared to removal of the Sacrificial bed and its support.

Please don't take my comments has pulling the machine down just comments based on quite extensive work building router based machines that can cut hard materials and still give an acceptable quality.! . . .

I didn't Jazz, it was what the drawings are posted for!

. The thing you and others should be aware of is that router based machines can never cut steel or aluminium like dedicated milling machines can.!!

I do appreciate that dedicated machines are the best way to go, they always are :-) and I would love to have space for more machines, but I will be working in a 6ft cubed area on my boat and I really only have space for this 1 machine outside the Pillar drill! Super accurate finishes are not going to be critical on the parts I make, they will be more art than engineering, so cutting speeds, hand de-burring and polishing, while a nuiscance aren't performance critical.

Wish you luck and keep the designs coming.

Thank you Jazz, I guess I'm always going to be in conflict with my ambitions for the way the machine HAS to be built and the way in which it will operate. As it stands the bearings take up a big chunk of the travel and I must admit I have run out of ideas how to reduce the gantry height or improve the Z Axis support without loosing even more travel or introducing the need for outside machine work! Any advice on how to achieve this and still maintain my production intent would be very gratefully received!

The only 3 rules here are:

1) I must be able to build it with just basic tools and a pillar drill.
2) There must be no physical outside help with the mechanical build - Virtual help with the design is OK!
3) As close to a 400x300 minimum working area as possible, within the above 2 constraints as possible.
3 and a bit) Sneaking in up to 100mm on X&Y is just about acceptable space wise, but I 'd rather avoid it!

That is the challenge I have set myself. Compromised performance will just have to be lived with, it is the nature of the beasty. Having said that the design can be changed to reduce the compromise!

Cheers,
Geoff.