The Journey begins.. new to me.. my first CNC - Black Cat

[Fivetide]

So.. I finally got the Black Cat running under NCStudio, and it works fine..although I have ordered a Mach 3 breakout board for the controller .. never mind it can go into another project or I’ll sell it on here.. it’s a 4 axis.. which gets me to thinking lol ..I have lathe, I need a drop saw and CNC software.. problem was I didn’t realise that NCstudio was a very simple program in reality , as ever I over complicated it , but it was easy to install and get running in the end.. you just have to find the right youtube videos.. Basically the ones in English.. not Ingrish
Next thing level the bed plate..

[Fivetide]

So now onto trying to level the bed. Heres some pictures , see what you think and what if you might do or if you have any suggestions I'd be greatful.
And heres a few secounds of my baby running :)

Black Cat CNC test - YouTube

[Tenson]

Get some of this in 2mm thickness

Then slip it under the track and put some holes in it to allow the screws to pass through. Tha website is nice as they will cut to the size you want (roughly).

[Fivetide]

Get some of this in 2mm thickness

Then slip it under the track and put some holes in it to allow the screws to pass through. Tha website is nice as they will cut to the size you want (roughly).

Bookmarked :)

So you suggest the tracks not the corner plate ?

[Tenson]

No, I'm not sure where it is best, but it seems better to use sheet than washers.

[Fivetide]

Ah ok good idea thanks :)

[Fivetide]

I used the 2mm sheet sugested by Tenson under bed on the rails, now as you all know I'm not an engineer so this is the closest to level its going to get. I did a vid of the plunge gauge its a 10 mm so by my reckoning its not that far out now. Sorry for the poor quality I tried it on my Go-pro.

Video

Now to put on a 1/2 in bed or something, source some screws and washers.. etc..

[Tenson]

That doesn't look bad at all :) With a sacrificial bed on there milled flat it will be very good.

[Fivetide]

That doesn't look bad at all :) With a sacrificial bed on there milled flat it will be very good.

Off to buy the bolts for one now :)

[Jonathan]

Not bad, but I bet you can do better...

Use the indicator as you have set it up in the video. Move the gantry so that it is measuring over one of the 4 supports (bearings). Now take readings every 20mm (or whatever distance you can be bothered with) and record them in a spreadsheet. Plot the graph and you'll find there will be some small variations due to the aluminium not being flat and a linear error due to the bearings not being at the same height, which is the bit we're interested in. Suppose you get something like the blue line on this graph:


As you can see, if a straight line is plotted using the blue curve, it shows the average gradient of the bed. If this function is subtracted from the readings, you end up with the orange line which shows the 'flatness' of the bed with these reading if the perfect size spacer was added. So once you've got the readings, use your favourite spreadsheet program to find the linear regression line and equation, look at the gradient of this line - in this example it is -0.0015, so if the distance between the blocks is 300mm you would need to add a spacer which is 0.0015*300=0.45mm thick. You should then repeat this test measuring parallel to the other axis, then over the other two bearings and you should end up with it being extremely close. The advantage with this method over measuring directly above the bearings is it will account for local variations that could otherwise skew the readings.

Just watched the video again and it looks lie the bed is bowed, can you take the readings and post them here then we can work out if it's worth proceeding?

From the video it looks like you're close enough, but if it was my machine I'd try this to see how much closer I can get it.