Thread: Ballscrews from LMB

It depends on your bearing setup on your machine as to what is required to be machined on the screw.
If you are going to make your own bearing mounts then provide him with a drawing so there is no confusion. I do a sketch (not to scale) in Paint but all dimensions are put on there so there is no confusion.
If you are going to use his bearing mounts then just ask that the screws be machined to suit his bearings.

I do not know your skill level so excuse this comment if I am out of order. Use angular contact bearing on one end of the screw. Either end will do but usual thing is to place these at the motor end. A standard deep groove bearing will be OK on the other end. These bearing will allow the screw to be loaded slighly to remove any end play - back and forward motion along the screw. There are other bearings such as thrust bearings but you will have to combine this with a radial bearing so much easier to use angualr contacts. LMB uses angular contact bearings in his blocks.
What you are trying to achieve is zero end play in your screw so that there is no backlash in your machine.

Thanks rodm.
I will be going with the bearing blocks that LMB sells. so i will just ask them to machine to suit their bearing blocks.

Hi,

When I order from Chai I provided the following re the ned machining:

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Re the machining of the ball screws:

1. At the BF end I need the ball screw machined to fit the internal diameter of the bearing and the groove for the retaining clip.

2. At the BK end I need the ball screw machined to fit the internal diammeter of the bearing, the thread cut for the lock nut (for a distance of 12 mm) and a 8 mm diameter / 16 mm long shoulder for the coupling.

I have attached a diagram to help.

[IMG]file:///C:/Temp/moz-screenshot-1.png[/IMG]-------------------------------------------------------

This worked out fine and Chai got it spot on. I have attached the diagram I sent. It was based on one that rodm posted if I recall correctly but modified to suit my particular requirements so may need to be changed to meet your needs

Grunto,
Do you have any diagrams/pictures of the BK21 mount, especially the mounting holes?

The diagram on Chai's eBay page is not that clear and when I asked him for a diagram, he pointed me at this website
The mounts there have different/extra mounting holes to the ones on the eBay site.

Geoff,

I am assuming you were meaning BK12 blocks? The image you posted was what the ones I got looked like - what are the differences between this image as the one Chai provided? I must admit I found some of images from Chai a bit hard to follow so I just Googled for other drawings. I used this document as a guide for the BK12 blocks but once I got the components I am just started building my machine based on the actual dimensions. If you tell me what specific aspect you need more information on I can go and measure or photograph the actual item if that would be helpful (I only got the parts over Christmas so the build has just begun).

BK12 it is.

The image on the eBay website does not show the 4 mounting holes as in the first part of the diagram I provided. It may just be a poor image.

BK12 it is.

The image on the eBay website does not show the 4 mounting holes as in the first part of the diagram I provided. It may just be a poor image.

Geoff,

Mine definitely have the 4 x mounting holes from the front, in addition to the four mounting holes from the top. I think the black metal just makes the holes difficult to see in the photo.

Excellent.
The ones in Chai's photos do not show 4 mounting holes on the front face.
I have an idea on what i require and will not make the final mounts until the parts arrive.

One last question is how tight do you need to do the lock nuts up?

Thanks

I was looking at mounting through the face but would have required a large diameter hole to allow the shaft to pass through. In addition the lock nut is proud of the bearing block so it would have required even a larger diameter hole if I mounted from that side.

Re lock nut tightening - good question! I haven't got that far yet so I am also interested in an answer.