8x30 A1S mill Ball-screw upgrade?

slow-poke

Ultra Member
Enquiring minds would like to know......

I took a look at the X axis lead screw on my partially disassembled mill and I think it looks okay (it certainly felt great), except where the power drive meshed with it, in that location it looks terrible. I have no plan to use the power drive because I will add either a stepper or servo motor as part of a CNC conversion.

While it's apart I want to at least consider upgrading the lead-screw to a ball-screw. To be crystal clear this is a hobby type application and I don't need (or want to pay for ) super accuracy.

Somewhere I read that decent quality economical priced ball screws are available, possibly on Ali-express but I can't recall?

If I decide to order:
Suggestions on vendor?
What details do I need to provide; length, diamter, thread pitch, details of keyways, diameter etc for original handles, what else?
What about the nut and how it mounts?
Cost?

Any words of wisdom are welcome, assume I know next to nothing about this topic.

Thanks in advance.
 
I recently order a set of 3 ball screws from eBay, nice units. If you are going this way consider getting double nut ball screws which remove the backlash and greatly reduces wear because of this.
 

slow-poke

Ultra Member
I recently order a set of 3 ball screws from eBay, nice units. If you are going this way consider getting double nut ball screws which remove the backlash and greatly reduces wear because of this.
Degen,

Can you provide a link to the ones you purchased?

What machine are you using these on?

Thanks
 

They are 16mm screws, I would have like to have gone larger but it is a clearance issue.

To be mounted on a BB CT054, Z axis is first as it requires it. X and Y require the couple of re and re's to get them installed, will update the oiling system at that point. Hopefully before x-mas.
 
What @Arbutus has is way tighter tolerances, but they are single screws not double screws (double is better). Additionally his lengths where too short for my applications.

Final note he's are great price for a great product if they work for you.
 

slow-poke

Ultra Member

They are 16mm screws, I would have like to have gone larger but it is a clearance issue.

To be mounted on a BB CT054, Z axis is first as it requires it. X and Y require the couple of re and re's to get them installed, will update the oiling system at that point. Hopefully before x-mas.
Degen,

Did you order mounting blocks for your ballscrews?

Dimensions of the blocks?

Our mills are similar, but not exactly the same, the X-Axis lead screw on mine is
22.12mm diameter
104.5 mm long

The bronze nut is 34.7mm tall, however the table appears to have about an additional 1/2" of clearance to the nut, so the mounting block looks ( need to measure) like it could be about 1.8 or 1.9" tall.

How do these dimensions compare to yours?
4EC49A6E-5D1F-4901-B951-CC6EBE85BBCF.jpeg
 
Degen,

Did you order mounting blocks for your ballscrews?

Dimensions of the blocks?

Our mills are similar, but not exactly the same, the X-Axis lead screw on mine is
22.12mm diameter
104.5 mm long

The bronze nut is 34.7mm tall, however the table appears to have about an additional 1/2" of clearance to the nut, so the mounting block looks ( need to measure) like it could be about 1.8 or 1.9" tall.

How do these dimensions compare to yours?
View attachment 40178
No I did not order the mounting block for the nut, going to make my own to fit, I based the size of the nut which I could squeeze in, which determined the screw size, ideally I should be one size larger but can only do as space allows.

Mount will be a Frankin fit.

This is why I mentioned earlier the X and Y are going to take longer to installer, several disassemblies and assemblies to size, fit and build as the mill must be used to manufacture the parts.
 

slow-poke

Ultra Member
I will need to do more measurement, the O.S. diameter of the ones you are using looks to be 48mm, that should fit in a custom block (likely what I will do as well), not sure if one size up will fit, I will investigate.

The bronze nut on mine has a single round mounting leg that points straight down that fits in a hole directly below the nut, then a capscrew intersects that leg to lock it in.

What material did you use for the mounting block?
Does yours mount the same way?

Most likely I wii have use the 16mm as well, I wonder how a 16mm ballscrew compares to a 22mm ACME screw in terms of holding a load?
 
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Single mounting hole for the bronze nut as yours, still working out the details but definitely not that detail.

The dia on the screw is more to do with defection under load, which has to do with the free length when moved to either extreme. I'm gambling the numbers are a bit conservative otherwise other action would have been required
 
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