Bended ballscrews. What i can do?

[ba99297]

Guys thanks very much for your comments.
You really help me understand that i an go on with my build as this is not a disaster.
Regards this straighten process i have some questions

Yesterday i borrow a dial indicator from a friend
Question 1
If i try to follow the straighten process as described here
Screw Shaft Straightness
and measure the TIR where should the node of the indicator touch ?
I am asking because if i put the node in the lower spot of the thread, as i turn the ball screw and have the indicator stable, the node of the indicator will pass from the lower spot to the higher spot of the thread( as the screw turns). I don’t know if i make my self clear.
Is ti logical to put the indicator node on the ballnut that has a cylindrical outer surface so i can capture the TIR.

Question 2
what is a logical distance for the V blocs

Question 3
How much pressure should i apply? I mean if i have a bend like that ) 1mm from the rotation center, i should apply a force to bend the the ballscrew to the opposite dimension so the screw take temporarily this shape (, and after i stop applying the opposite force the screw become straight | . This temporary opposite force is it logical to bend the screw 1mm ( temporarily ) or more? Again i don’t know if i make my self clear.

Anyway thanks for your patience.

Vagelis

[JAZZCNC]

Vagelis.

Q1 You can't use the Node of the indicator directly on the screw you need something flat between the screw and the indicator node.

Q2 For measureing then you want over the full length of the screw. For straightening then it depends on the bend amount and where on screw it's bent. Often just moving blocks slightly in ward of ends and light pressure is enough to straighten.

Q3 Trial and error I'm afraid.? . . . How longs a piece of string.? Often just a little more than the amount of bend will do it but could require more depending on where the bend is on the screw.?

If you go too far then just tweak it back but often you'll creep up on straight. It's honestly not difficult to straighten screws just time patience needed. Don't be afraid you would have to be Very rough to destroy the screw. Just protect the threads while applying bending force and you won't have any problems and you'll be surprised how little it takes to straighten them.( Or bend them.!!)

[Wal]

I am asking because if i put the node in the lower spot of the thread, as i turn the ball screw and have the indicator stable, the node of the indicator will pass from the lower spot to the higher spot of the thread( as the screw turns). I don’t know if i make my self clear.
Is ti logical to put the indicator node on the ballnut that has a cylindrical outer surface so i can capture the TIR.

Would you not use a flat tip probe - like the one 2nd from the right in the pic..?



Wal.

[JAZZCNC]

Would you not use a flat tip probe - like the one 2nd from the right in the pic..?



Wal.

Yep them's what's needed Wal but like finding Hen's Teeth unless your prepared to splashout on expensive dial gauges and then they are expensive for a one off job.!

Edit: I retract that statement I've just found this set at Arc eurotrade (bottom of page).!!. . . http://www.arceurotrade.co.uk/Catalo...nt/Dial-Gauges