[Calico]

I have 2 meters long a pair of linear bearing for the table, yes it's huge.

my question is ... How can I make the linear bearing parallel/align ?
I read the thk book that it required reference to install, but how if I do not have reference ?

actually I made the reference but not sure it's 100% straight.

my other question is how do I know my reference is 100% straight ?

I saw some Site explaining about this but can't find it anymore.

please advice me

regards
rud

[eternauta3k]

As far as my intuition goes, try measuring the diagonals. If they aren't similar, they aren't parallel.

[acondit]

Calico,

First, bolt down one rail. Then you mount two linear bearings on each rail. Then connect the two bearings on each rail with the plate to which they will be attached. Then connect those two plates with a temporary stretcher between the two rails. Slide the bearings to one end of the two rails. Clamp that end of the second rail. Slide the bearing assembly to the opposite end of the two rails. Clamp the second end of the second rail. Then test that the bearing assembly slides freely back and forth. If so, then they are parallel. Then bolt down the second rail.

http://www.cnczone.com/forums/showthread.php?t=10425

You can look at the pictures in my first post in the thread above to get the idea.

Alan

[mxtras]

Diagonals will give you squareness. Flatness, squareness and paralellism are related but you can have one without the others! Getting all three at once is tough.

Scott

[ger21]

You might want to read this - How to get straight edges. http://home.alltel.net/leswatts/straightedge.html

[jcc3inc]

Sir:

Here's another possibility: suppose you setup one side rail as the "master" side. Make it as straight as you need it. Fasten it rigidly to your carriage. Then place the "slave" side rail making it as close to parallel and in the same plane as the master side. Now connect the bearing block to your machine carriage with a flex plate, a thin spring steel piece so that the slave side handles the vertical load but NOT a side load. This allows some misalignment without losing the load carrying ability.

How are you driving your carriage? Single side? Dual side?

Regards,
Jack C.

[atifeh]

Hello,

I encountered the same problem with my assembly. I found it would be much easier if it would be simulated on a cad program.

For the X axis, suppose we have assembled one rail in a planar (level in perpendicular directions) position. We lay the second beam and measure the diagonal. We observe that both measurements are equal. BUT the second beam could be:
1. In a “pitch” position around its center.
2. Parallel to the reference with no pitch angle but have an offset in height.
3. In a “roll” position.

Any of the above 3 conditions could also be valid which complicates the situation. The attached picture shows these conditions.

All these situations arise when the second beam is not laid in the same plane as the reference rail resides.

Therefore if we establish a planar surface case 1 and 2 will not happen. We will only have to adjust for “roll” and we actualy could reduce 9 problems to only one problem. “Yaw” will be easily measured since the diagonal measures will not be equal.

Nader

[Rance]

Interesting link Gerry. Seems that I'd seen that referenced before. I also noticed he had some rails for sale. [ surplus profile linear rails from THK, IKO, and others. Price is typically one third of manufacturer's list. ] Just an observation.

Rance

[15mgtar]

You might want to read this - How to get straight edges. http://home.alltel.net/leswatts/straightedge.html

The link is dead can I have a new one?

[jsheerin]

Try using google - the third search result:

http://lmwatts.com/straightedge.html

[JimPAC]

Think like a Jig Builder!

Go to Sears and for a 100 bucks buy one of there laser sets. Install One and reference from there!

Good Luck