How to Check Towers

Does anyone have any suggestions how to check the squareness of delta towers?

I rest one side a carpenter's square on the bed and see how well the other side aligns with the towers.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

There are two separate things you need to check:
1) Squareness of the towers to the horizontal extrusions
2) Squareness of the towers to the bed

These are two completely separate issues.

To check 1, you need a carpenters square or angle finder, as well as some diagonal cross braces. Put your square on a horizontal extrusion and square up a tower. When it's square then attach your diagonal brace. Then go around the frame, squaring up the towers against the horizontal extrusions. There are six angles to check (two on each tower).

I only needed two braces to fully square my delta up, I think that this is enough to fully square it in every dimension assuming that top and bottom triangles are all perfect 60 degree triangles.

Once you're totally happy with this, it's time to square up your bed to the towers.

This is easy if you have installed a spring underneath each of the three attachment screws. I like to put a dab of loctite on the screw where it goes into the T nut. This means that you can adjust the level of the bed, and then once the loctite has set you can remove the bed, then replace it and you won't need to relevel it.

Mine is so consistent that I don't need to do a Z probe or recalibrate, even after removing and putting back the bed.

Hope this helps.

Quote
nebbian
There are two separate things you need to check:
1) Squareness of the towers to the horizontal extrusions
2) Squareness of the towers to the bed

I would change #2 to be "Bed should be parallel to the horizontal extrusions"-- mainly, because it's easier to check (calipers between extrusion and bed).

Also, if you've already squared the towers and the horizontals, then squaring the bed is a redundant (and more difficult) exercise.

Quote
nebbian
There are two separate things you need to check:
1) Squareness of the towers to the horizontal extrusions
2) Squareness of the towers to the bed

These are two completely separate issues.

To check 1, you need a carpenters square or angle finder, as well as some diagonal cross braces. Put your square on a horizontal extrusion and square up a tower. When it's square then attach your diagonal brace. Then go around the frame, squaring up the towers against the horizontal extrusions. There are six angles to check (two on each tower).

I only needed two braces to fully square my delta up, I think that this is enough to fully square it in every dimension assuming that top and bottom triangles are all perfect 60 degree triangles.

Once you're totally happy with this, it's time to square up your bed to the towers.

This is easy if you have installed a spring underneath each of the three attachment screws. I like to put a dab of loctite on the screw where it goes into the T nut. This means that you can adjust the level of the bed, and then once the loctite has set you can remove the bed, then replace it and you won't need to relevel it.

Mine is so consistent that I don't need to do a Z probe or recalibrate, even after removing and putting back the bed.

Hope this helps.

I guess you have to make sure the horizontal extrusions are all in one plane first.

Quote
SlowFoot

I guess you have to make sure the horizontal extrusions are all in one plane first.

How could they not be?

Three points define a plane.

Edited 1 time(s). Last edit at 10/03/2015 05:05AM by nebbian.

Quote
nebbian

Quote
SlowFoot

I guess you have to make sure the horizontal extrusions are all in one plane first.

How could they not be?

Three points define a plane.

Because the horizontal extrusions are, at best, three lines, that is six points.