Linearmotionbearings

[kolias]

For my 2 previous cnc’s I ordered all rails and ball screws set from Mr. Chai (linearmotionbearings) and have been very happy with the quality and delivery time. Last time I placed an order was in April-2013 but now I can’t find him. Anyone knows if he is still in business?

In a ball screw for example RM1610x1120mm total length, how do you know what is the length of the threaded part of this ball screw? I have seen drawings related to the machining of the ends but never seen a drawing related to the threaded part length.

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[Bob Madoran]

For my 2 previous cnc’s I ordered all rails and ball screws set from Mr. Chai (linearmotionbearings) and have been very happy with the quality and delivery time. Last time I placed an order was in April-2013 but now I can’t find him. Anyone knows if he is still in business?

In a ball screw for example RM1610x1120mm total length, how do you know what is the length of the threaded part of this ball screw? I have seen drawings related to the machining of the ends but never seen a drawing related to the threaded part length.

Not all vendors machine the ends the exact same way. If the overall length of the screw is 1120mm, the length of the threaded part should be around 1050mm. The end that has the two fixed bearings will loose about 60mm of thread and the end with the floating single bearing will loose about 10mm of thread. But again, it depend on who machined it.

If you are trying to figure out how much travel you will get out of a 16xx ball screw, a rough estimate would be to subtract 125mm from the total length of the screw. That allows for a loss of 75mm for the machined ends and a 50mm loss for the nut.

[kolias]

Thanks Bob for your time, at least what you are saying is a fair rule but no accurate enough if you want to be precise. In addition the total length you order is not accurate either. I don’t know why they have detailed drawings for the slide rails and bearings but there is nothing for the screws which is also so important

[Blitz G Coder]

eBay store called linearmotionbearings items in linearmotionbearings store on eBay!
It is maintained by user linearmotionbearings2008.
I have had a email from linearmotionbearings2008 signed Chai.

Also Chia mentioned in:
http://www.cnczone.com/forums/bencht...75007-cnc.html
http://www.cnczone.com/forums/diy-cn...rings2008.html
http://www.cnczone.com/forums/open-s...51479-cnc.html (third message down, somebody with a name like yours, has also added a link to his store!)

[kolias]

Thanks Blitz for the help, I sent email to Mr. Chai and waiting for his reply