[samsagaz]

Hey guys, i purchased ballscrews and bk12 blocks. I want to know if someone have some doc or video about wich is the right way to connect the ball screw into the End Supports BK12 and BF12.

also i noticed that the bearings from the supports are not fit very well, and can be removed easy, is that OK? i will need to glue it when the machine is finished? Regards

[robrmcc]

This might help with that.

Can't comment on your bearings. The single bearing support for the floating end of the ball screw should be a sliding fit as it has to move around. Never had the other bearings out.

Rob McC

[samsagaz]

oh, yeah, just can get out one of the beargins from one of the support

[samsagaz]

if i use the lock nut on the fixed side, i get the ballscrew fixed, i need to lock the nut a few mm away from the support?

[louieatienza]

The fixed bearing block should have come with a spacer or two, possibly different sized. You don't need it for the back of the nut, but most probably for the front. There shouldn't be much if any thread left on the bearing journal

[samsagaz]

o i dont have spacers :S

[Walky]

if i use the lock nut on the fixed side, i get the ballscrew fixed, i need to lock the nut a few mm away from the support?

On the BK block, the locknut is there to prevent the screw from coming out and to press against the bearing's ID to create preload and prevent backlash; it needs to be pressing against the spacer (which presses against the angular contact bearing), so there must be no distance between the nut and the block. The nut's set screws will keep it in place (hopefully). If the nut rubs too hard into the block's rubber seal, you might need to press the seals to get them a little deeper.

It's no problem if both angular bearings can slide back and forth with the BK block disassembled, but... it IS a problem if they do when the block is closed (the 4 screw cap installed). This is a common problem with chinese blocks and can be easily fixed by using shims to fill the gap between the bearing's OD and the block. This MUST be fixed, else you'll get backlash and the whole point of using ballscrews is defeated. Don't glue the bearings, it will fix nothing, and might actually cause more problems.

So, the block must press the bearing's OD from both ends, and the screw and locknut must press the ID. In both cases there must be absolutely no gap, else there will be backlash.

The BF (small) block is supposed to have it's bearing loose, since it helps compensate for the thermal expansion of the screw.

[Walky]

o i dont have spacers :S

So, your BK blocks don't come with small steel tubes inside the rubber seals?

[samsagaz]

So, your BK blocks don't come with small steel tubes inside the rubber seals?

Found it!

Gracias amigo! ahora voy a ver si logro traducir el texto del post anterior para ver si armo bien los soportes

Saludos desde Argentina

[Walky]

Found it!

Gracias amigo! ahora voy a ver si logro traducir el texto del post anterior para ver si armo bien los soportes

Saludos desde Argentina

¡Excelente!, cualquier duda al respecto me dices y te la aclaro, por cierto a los "shims" se les dice arandelas (son como golillas pero con un grosor de fracción de mm).