[toneV8]

Thank you LongRat
I meant disassembled bearings from blocks.

[LongRat]

Ah, sorry. Don't have those pics. Mine were full of crap, grit, dirt and even a piece of bamboo! They were also assembled the wrong way. Needed disassembling, cleaning and rebuilding.

[bogus105]

so what is better choice: ball screw with two nuts for backlash elimination from Rotton.com (5/8'' dia, .200'' lead) or screws with one nut per screw from mentioned earlier ebay seller from china?

which solution is more resistant to wear and more accurate?
pls help as i'm about to place an order shortly

[Flenser]

I haven't really read anything to convince me either is more accurate or more resistant to wear. I used the Chinese screws with two nuts, but had Rotton had the better price at the time I would have gone with them.

[LongRat]

I've been happy with my screws from Linearmotionbearings. I would buy from him again. Depending on the price, why not just get 2 nuts per screw from him? When I was buying screws last year, there wasn't any other source worldwide that I could find offering similar quality products anywhere near that price.

[LeeWay]

When I have used the Roton/Thompson double nuts, I was happy with the results. There are more moving parts, but I think that may actually take off some of the load. The is also a need for more room with a double nut version. If real estate is tight, then I might go will the ball screws off Ebay.

Another thing I like about the ones I have used is I can get the exact length I need. They will make them up for you on Ebay as well. A lot less work with them too.

[LongRat]

One thing though, don't go for the Chinese screws just because he claims <0.015mm backlash. This isn't true. Mine came up 0.020 to 0.035mm.

[Davo J]

When I bought my 25/5 ball screws and nuts from him I ordered 2 nuts per axis, I think the nuts were 25 or 28 US dollars each for that size. I got them and I found some were anti backlash and some were standard nuts, not sure why.
I have heard a few bad reports about the cheap Roton screws and nuts having worn out early in a non stressed situation. I cant find the thread at the moment.
Dave

[bogus105]

Hoe does antibacklash nut looks like? Is there some kind of backlash adjusment screw or what?

[BallScreWE]

duplicate post.

[BallScreWE]

That is theorectically long enough to include two seperate circuits which are mated together with a key and sandwiched together with spring washers (the number of washers can vary from 1 to many). Removing backlash is a process of altering the space between the two sides of the nut via sanding down the thickness of the washers.

This is usually only a process associated with roll thread screws as grounded ones geenrally hold tighter tolerances stock. sans spring washers.

Dave Winter
WinterEngineering.com

[Davo J]

Hoe does antibacklash nut looks like? Is there some kind of backlash adjusment screw or what?

Hi,
The only difference in the anti backlash ones he sells is they have larger ball bearings in the 2 circuits to take out the backlash. To look at them you couldn't tell the difference.
I didn't need the anti backlash nuts because I am using 2 nuts loaded against each other with bevell washers like explained in the above post.
I will just change out the balls to smaller ones to save over stressing them in all directions.
If you have a look around the site you will see all sorts of ideas for putting 2 nuts together to over come backlash. Manufactures have ready built ones but they get very expensive thats why a lot of guys build there own.
There are also a lot of guys using just one anti backlash from this guy with good results.
Hope that helps a bit
Dave

[bogus105]

this is what Chai wrote:

'
Hello,
All of our ballscrews are anti-backlash.
Thanks!
Chai

- linearmotionbearings2008
'

i think i'll just order two nuts per axis

[Flenser]

All the ballnuts I got from Chai, two per screw, were anti-backlash. The channels for the balls are offset to provide a light pre-load. The couple of nuts I took apart didn't appear to have oversize balls and were easy to reload. The RM2005 nuts have 3 circuits, but the middle circuit appears to have fewer balls than the max that will fit. I think I could have put two more in than came out.

[Davo J]

I just had a look at his auctions and they are all now anti backlash nuts he is selling with them.
When I bought mine last year he had either, must be easier just to have them all anti backlash to save any mix up maybe.
Dave

[LongRat]

They are all labelled 'anti' backlash, all of the ones I bought were at least. This does not equate to 'zero' backlash. If the tracks were offset to remove all backlash, in combination with a rolled screw of variable pitch surely there would be tight spots in the rotation of the nut? I'm not sure you can preload the backlash out of a rolled screw system without compliance in the preload system. The ballscrews I received were all butter smooth, but to get zero backlash all would require a second nut with a sprung or otherwise compliant preload system.

[MrWild]

After needing to repack my Roton screws to get rid of a huge amount of lash, I ordered a set of three along with some couplings from linearmotionberings2008. They sent just the couplings registered mail BUT charged it to the ballscrew purchase. It now looks like they shipped the ballscrews in my Ebay account! If they give me problems I'll take pictures of this dinky little package and do a PP charge back

[Hans_G]

You'll get more backlash from their helical couplings than from the single anti-backlash nuts. Price is good, but if there is a lot of friction in the axes, you'll want to replace the couplings with something stiffer.

[MrWild]

You'll get more backlash from their helical couplings than from the single anti-backlash nuts. Price is good, but if there is a lot of friction in the axes, you'll want to replace the couplings with something stiffer.

For sure. They look about 20mm OD and are made out of aluminum. What the machine has now are solid. He lists these as encoder couplings, and they are indeed so light duty that's all they appear to be worth. I'll probably use these on a mini desk top wood router after I see how bad they are on a X2 with 285inoz steppers

[millhead]

They also sell a smaller 12mm Ballscrew (1204).
Will this be a better fit for the X2 X axis? Would a 12mm Ballscrew be rigid enough for the X axis?

I was on the verge of ordering a 1204 for the X axis, and 1605 for the Y, but thought I should get some feedback first.

Thanks.

Daya.

Well, I went ahead and ordered a pair of 1204 ballscrews for the X and Y axes of my X2. They were ordered on July 31, and I received them on August 18.
The X was 470mm overall length, with a length of 55mm turned down to 8mm, with a 8mmx1mm thread. The Y was 260 mm overall, with the same end prep.
The two screws, two nuts, custom end prep, and shipping cost me $127.

I have not installed them yet, but they are straight, the nuts can be moved by hand end to end with no binding anywhere.

I think that the smaller ballnuts will fit without modifying the saddle, but I will have to make a couple of Ballnut carriers since the flange on these small nuts is not big enough to fit the saddle slots directly.

Also, I will need to add an Aluminum sleeve to the 8mm ends and turn down to 12mm and 10mm to fit the Y and X bearing blocks respectively.

I will comment on the performance when they are done.

Daya.