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sfallan
26-09-2010, 10:40 AM
Gents,

Now that me machine is running, not 100% but running I thought I would check how level it is. It was suggested that I purchase a DTI clock which I did and began to check the Y Axis. The following was noted and I would be greatful of feedback comment.

I have installed 4x80x40 alu sections to help stiffen/support my sacrificial bed. The supports are at 170mm ctrs so I check at these settings.

0, 170, 340 and 510mm ctrs

0=0 in the DTI clock.
170mm on the Y = 1.36mm
340mm on the Y = 1.48mm
510mm on the Y = 0.75mm

If I were to level 0 and 510mm this would still leave 170 and 340 out. I am assuming that the supporting Y rails are deflecting causing the readings above.

Im a total novice to CNC but work within Architecture therefore undertand some things.

Any guidance would be apprecaited. Who ever said that having a hobby CNC would be easy.

John S
26-09-2010, 11:05 AM
Don't bother about it, it's less than 100mm :whistling:

No seriously you will always have some errors on a build like a gantry, the answer is to machine your sacrificial board in situ to flatten it.

Someone put a program on here I think to do just this [ or may have been on the Vectric forum ] you just plug in max travels and depth of cut and it goes all over the bed and takes a shaving cut.

[Edit]
Or use the surfacing wizard in Mach.

sfallan
26-09-2010, 12:49 PM
John,

Surely machining the SF bed will only provide me with a dished SF bed? If 1-2mm seems ok then I will do me best to limit this as much as I can. I am only cutting throught MDF, plastic and die bond so I guess deeper cuts are what is required. If 3d controuring then I will have to try my best to take this into account.

John S
26-09-2010, 12:52 PM
Yes the bed will be dished but not dished in relation to the Y.
It will be dished in relation to the base but parallel to the Y.