[robe_uk]

Hi All
Like many i've been lurcking about for a while trying to learn as much as i could before attacking a cnc project.

Why a 25hr day?? well it takes me soooo long to do things and i've to many hobbies

I started by downloading the jgro plans, I had full intentions of building my machine out of mdf but to my luck work was dumping some extrusion so have decided to use that instead. So now this machine has turned into an all metal affair.

[robe_uk]

I started by making the gantery, I sort of just work 'on the fly' when it comes to sizes, but I intended to make a machine that would be able to mill parts for model rc aircraft.

I also have got the bearings fitted that will run along my guide rails.

[robe_uk]

I will have to modify the bearing design as there is no way to adjust them if they are not 100% parallel to each other. This could mean that a bearing may not run along the rails correctly. At this point I have not tested this yet.

[robe_uk]

As this is an all metal machine I got a friend to weld me a box section frame to act as a soild base.

[robe_uk]

To this base I have been able to attach aluminium end plates which will support the guide rails and table.
I have used aluminium angle as the support for the mdf table bed

[robe_uk]

The guide rails are held in place with centering blocks which can be used to aline the rails.

[robe_uk]

For the z axis i saved some linear bearings from the skip at work. I have most of the z axis complete but no pictures so far, am hoping having this log will help me keep track of where i am and what i have to do..

[robe_uk]

As far as the electronics side of things go I plan to use the picstep drivers as I have 10 of the diver chips LMD18245

http://www.fromorbit.com/projects/picstep/

Although I have quite a lot to learn, ie. etch boards, program pic chips.
I am going to try toner transfer method for etching so I will let you all know how I get on considering its all new to me. Might try photoboard as I made a uv light box which I made, but again never used
Likewise with the pic programming will be a sharp learning curve, although I have i programmer I have never used. (more unfinished projects )

[robe_uk]

I have not played around with the software side of things to much but will try turbocnc as I saved a pc from the skip which is a 200Mhz PII so I guess dos based is best for this machine, after all it will be out in my shed/workshop so I dont want a good machine out there.
As you can see I saved a few useful things from the skip at work, they are so wasteful, if its dirty bin it???? oh well one man rubbish, another mans gold

[robe_uk]

Well thats my posts for tonight, an hours work to show what I've done in a couple of months, hopefully as i post stuff as i do it there will be a bit more detail included.

One thing no one tells you at the start of all this is the mess your workshop gets into, I've had to pack away my current plane build project to make room, and now there is a helicopter to add to the clutter.

Like I said, 25 hours maybe more needed lol, its 1:50am here am off to bed

[DieGuy]

Poof I grant you a 25 hour day, problem is the hours are only 57.6 minutes long!

you are making great headway.

[santiniuk]

Watching with interest. Looking good so far !

You won't be dissapointed with the picstep drivers. Great boards, just shout up when your building them, there is a lot of help on here.

Good to see another 'skip-rat'

Cheers

[10bulls]

Wey Hey! Nice to see another metal contraption taking place!
I'm afraid the best I can offer you is 24 hours 39 minutes; However this would entail relocating to Mars. Another bonus is you wouldn't have to worry about moisture in the workshop again.

I like your rod adjusters. Did you do them on a lathe or use some other cunning means?
Are you going to put some plates on the side of the gantry to make it more rigid?

[robe_uk]

Hi Guys thanks for the support nice to know am not just rambling off into cyber space lol.

The rod adjusters where made using hole saws, I had to cut both hole at once as I had only one saw holder bit and it wasn't the right type for the lager bit. The saws are 52mm for the larger and 25mm for the inner one.
Its a bit crude but when needs must and I wish I had a lathe

I must likely will add extra support to the gantry sides, I will wait to see what turns up in the skip lol.

[robe_uk]

Hi started to put things together just to see how things are going.
Mounted z carrier to the gantry, had to load bearings to take slack from bearings, I think there is a lot of flex in the 20mm pipe and I may look into getting soild rod. At the moment I have the gantry cross members tight to the rods to stop flex.

[robe_uk]

I fitted evrything together and it gives a good idea of how the final machine will turn out, I have put some measurements on to give an idea of size.

I will have a final cutting area of 42x69.5cm and a max height of workpiece 13cm

[10bulls]

Can you not just keep the gantry cross members that way? That sounds like an elegant solution. Your gantry is going to end up very heavy when you're finished (even with hollow pipe). I think your table (X axis?) rods will definetly need some supports (and possibly made solid) as they bear the most weight. I've read some people people fill their pipes with concrete to increase strength (and improve dampening)

Very clever method for the rod supports! You could bang out lots of supports that way fairly quickly.

[robe_uk]

Hi 10bulls, yes I agree about the x axis rods so I will most likely get some solid rods as there might be no simple way to support them with the gantry lay out.
The weight is really adding onto this machine add I wonder if my motors will be up to the job. Its hard to source good 'cheap' steppers here in the UK.

I have to get started on lead screws and mounting the motors, I like the way xairflyer has used 12mm rod and turned the ends down to 8mm. I will have to get a mate to do this for me or i may just use 8mm to get started.

Anyone advice on floating nuts?

[10bulls]

... as there might be no simple way to support them with the gantry lay out.

Can you not move the 'under gantry' cross piece above the x-bearings so the rods are free underneath for supports?

...Its hard to source good 'cheap' steppers here in the UK.

I got mine from http://www.arceurotrade.co.uk/ ~£30 for 180Ncm (255oz/in).

Anyone advice on floating nuts?

Tapped delrin (or nylon breadboard) works great for starters. Fancier AB nuts can be made later.

[sploo]

Hi robe_uk,

The machine's looking great!

Can I ask how you're cutting the plates of aluminium?

Cheers.