Ensuring Rails are Coplanar
 

At 11:00 minutes along this video the "Wood Whisperer" uses two strings to ensure two rails he is setting up are coplanar.
http://www.youtube.com/watch?v=qtkBZHLJyD0

This method should be quite useful to determine the Mechmate rails are in the same plane (after leveling and straightening of course).
The method could be improved by being a little more particular with where the strings cross the top surface of the rails, that is crossing at the exact same points on each of the rails.

Ross

Thanks for the tip Ross, Good info.

Great idea. I used 4 tubes filled with water, and a common reservoir, to get the 4 corners of my rails on the same plane. Didn't totally trust it.

This method seems much more fool-proof.

i cannot believe that my machine is coplanar.. but if you think, all the metal pieces are calibrated and dont bend. so if you follow the plans your machine have to be " perfect "

Just for future builders; Metal does bend, especially when welding. And metal is never perfectly straight. So even if you follow the plans to the mm, you have to follow procedures to get things (rails table, gantry, etc) straight and coplanar to each other. Methods are described on the forum regarding the subject.

Fox....

Funny, Machine #5 and #28 I got lucky with nice steel.....#58 was a BUGGER to get sorted out.

If you could only buy a bag of luck at the hardware store.....my life would be sooooo much easier :D

I used 50x100 (2"x4") square hollow section for my 2nd 5'x20' bed... damn it took forever to sort everything out!

I buy lottery tickets occasionally, but they don't come with any luck.:confused:

Ken, you have a 5x20 bed? How have I not known this or seen pictures before now????

His plasma cutter is compensensational* ... it's HUGE !






*pun intended :D

Here Darren
video

Ken, I'll say it for Darren, That's Cool! I want one

That is very cool Ken.
I've thought of building one, but I don't know how much use it would get once done.
Of course, when I started #101, I had no idea how much I'd use it.
You are an inspiration.

Tom, Darren,
surely you can build one for yourself :D

Yep:)

Steel is hard to work
 

My C channels are quite straight, but I want they become more planar and perfectly at 90 degrees, in order to reduce the using of shims.
I have two long and very straight (more than 3 metres) pieces of extruded aluminium (the sides of my trailer) and I want use they to create a long planer. The problem is that the steel is hard to work. If I will glued, on the C channels, two thin floor listels of hard wood, I can easly work it with an hand electric planer or router. After I will put the rail on the perfectly planar wood. Do you think that is a crazy job ?

steel C- channel perfect 90 degree? Dream on... Unless you can find someone who can surface grinder 12ft or 4 meter long...

To me, shimming is easier than planning wood. not to mention cheaper. :p
I can get waste coke cans for free anytime of the week.

Will your wood stay straight with weather changes? Steel will stay better.

Crazy idea -> use the shims.

Or if you insist use special (extra liquid-/ self leveling ) epoxy resin on top of steel beams (builds dams with clay). Read cnc zone for more on that.

Which ever method you use, you will still has to shim.
There are no significant difference in the work and cost between a stack of 20 pieces of shims and 2 shim...