[LazyMan]

Hi, I was looking into .631 .2 ballscrews and homeshopcnc was the only place that I have seen that will sell them to you without all that quote nuissance? Anyone know where I can get them?

[fatal-exception]

How about nookindustries.com ? Just tell them you want plain screwstock, no machined ends.

Probably slightly more expensive than homeshopcnc since your aren't buying in bulk, but the same stuff.

Maybe it's a sign. Look for something even better???

Paul

[DR-Motion]

Try here http://www.reidsupply.com/aDetail.as...nook+ballscrew
About as cheap as anywhere and they also ship to Canada

[LazyMan]

How about nookindustries.com ? Just tell them you want plain screwstock, no machined ends.

Probably slightly more expensive than homeshopcnc since your aren't buying in bulk, but the same stuff.

Maybe it's a sign. Look for something even better???

I requested a quote for a few ballscrews from nookindustries.com but havent recieved anything from them and I have a feeling they arent going to take me seriously. I was looking for the XPR series with a lead error of .001"/foot. The only thing better would be some precision ground screws but I cant afford that. I remember from homecncshop it cost $3 an inch and $60 for a preloaded nut which was not bad. I have looked at other manufactures and havent found a preloaded nut that costs less than 150$ Im looking for a source for Hiwin screws with no luck.

[LeeWay]

Mcmaster Carr sells rollled ball screws. Similar to Nook. The ones I got were Thompson. Not preloaded though.

[Cartierusm]

Try this http://www.roton.com/ I'm using them in mine. Awesome and the prices are dirt cheap. I use 2 ball nuts on each axis and use a spring between them to set the "preload" and I get no backlash at all and it will self compnesate for wear in the future. I didn't buy the ball nut mounts though, I wish I had them, but I still wouldn't buy them at $35 a piece they are more expensive than the ball nut which is ridiculous.

[eloid]

Try this http://www.roton.com/ I'm using them in mine. Awesome and the prices are dirt cheap. I use 2 ball nuts on each axis and use a spring between them to set the "preload" and I get no backlash at all and it will self compnesate for wear in the future. I didn't buy the ball nut mounts though, I wish I had them, but I still wouldn't buy them at $35 a piece they are more expensive than the ball nut which is ridiculous.

did you over size your ballbearings and by how much?

[LeeWay]

Usually if you go the extra cost for a double nut, there is no need to preload the nuts with bigger balls. Alternating larger balls is usually only done on single nuts. I don't reckon it would hurt anything though. If you can locate the proper balls, they are generally pretty cheap.

[whoafat]

I procrastinated too long and now I find myself in the same situation; lloking for a source. Hoss's webpage mentioned www.grainger.com as a possible lowcost alternative. I could not find the specs for these rolled ballscrews on their site, but someone in the Grizzlyminimill group mentioned that a sales rep told him the error was 0.003/ft. I would be interested to know if we can do better for what grainger chrges.
wilfred

[LazyMan]

Try this http://www.roton.com/ I'm using them in mine. Awesome and the prices are dirt cheap. I use 2 ball nuts on each axis and use a spring between them to set the "preload" and I get no backlash at all and it will self compnesate for wear in the future. I didn't buy the ball nut mounts though, I wish I had them, but I still wouldn't buy them at $35 a piece they are more expensive than the ball nut which is ridiculous.

Yep, I have used them in my machine here and used a simalar preloading method as you.

http://www.cnczone.com/forums/showthread.php?t=50790
http://www.cnczone.com/forums/attach...7&d=1200786671

Im really looking for something that will hold .001 per foot, has a preloaded nut with wipers on it.

[Cartierusm]

I don't think grainger would be cheaper than Roton. As for the Balls I have larger balls only because I didn't pay my prostitute and she knocked my junk around, now they're huge...oh you mean my ball screw balls. Leeway is correct the reason for double nuts are to eliminate the PITA task of finding then changing out the ball bearings. The problem is unless you know exactly what to do and what to get you won't know the exact backlash until the machine is up and running and you can measure it. With my method there is zero backlash and it's easily adjustable if your parts ever wear, which is most people's situation would be very rare. I figured my way was easier as the ball nuts are only like $23.

[whoafat]

Cartierusm,
You are right. Both http://www.roton.com/ and Granger weere mentioned as sources but the reference to the lower priced was indeed roton. Additionally, the nuts are square and if one is to follow Hoss's approach, one nut must be rounded off for only one of the axes so that they it will fit; don't remember if it is the x or y axis,
Wilfred

[Eurisko]

Does anyone know the specs for the Roton ballscrew?

Specifically, what is the lead accuracy per foot?

I'm thinking of ordering the 5/8 screw with a double nut.

What kind of accuracy can I expect?

[LazyMan]

If memory serves, the roton screw has a lead error of .003"/foot and the ballnuts can have up to .006" of backlash.

[lgalla]

Eurisko the lead accuracy is .009/ft or transport grade.This sound's bad but this is not backlash.If you drill a hole in a part and then on another part they will match and be .009 out.This is repeatability due to accuracy per ft.Backlash is another story,concerning the nut.If the nut has zero backlash your parts will still be out by the amount of lead accuracy.
The double nut listed only has a higher load rating.You need 2 nuts with spring washers or what ever to reduce backlash.
BTW CNC Zone owner used roton on his mill and is quite happy with the results
Larry

[LazyMan]

Eurisko the lead accuracy is .009/ft or transport grade.This sound's bad but this is not backlash.If you drill a hole in a part and then on another part they will match and be .009 out.This is repeatability due to accuracy per ft.Backlash is another story,concerning the nut.If the nut has zero backlash your parts will still be out by the amount of lead accuracy.
The double nut listed only has a higher load rating.You need 2 nuts with spring washers or what ever to reduce backlash.
BTW CNC Zone owner used roton on his mill and is quite happy with the results
Larry

Ouch. Lead accuracy for these Roton screws are everywhere on this forum. If the screws are indeed .009/ft I would definately look into some cheap thompson or nook screws rated at .004/ft. So does anyone have a source for .001/ft screws?

[Mike Nash]

Has anyone using any of the ballscrews actually measured the lead error in theirs? I know they are not guaranteeing it's going to be x out per foot, just that it may be. But does the error, if any, tend to be consistent? If the axis is rescaled to match then no big deal. If it varies along the length of the screw, that's another issue. Or if the threads are "drunken", e.g. repeatably out over a 1/2 turn, but coming back in as the turn is completed. I have a set of the Roton 5/8" 0.2" lead, but I don't have my mill back together yet. And it may be awhile as I'm looking into trying to true the ways up first.

[LeeWay]

Ouch. Lead accuracy for these Roton screws are everywhere on this forum. If the screws are indeed .009/ft I would definately look into some cheap thompson or nook screws rated at .004/ft. So does anyone have a source for .001/ft screws?

I think at .001" per foot, you would be approaching either ground ball screws or factory preloaded. You might be able to get better with a double nut as well.
I have never measured the Thompson's I have. They are accurate enough for what I do. The .004" per foot may be an average or even a best case scenario type spec. Since they are rolled, I would imagine it may be an average.

[cueshark]

i have not done this, but mach has a screw mapping setup. supposebly you can move so far read the measurement or the differance from what it should be & put that info into mach & it will go the right distance as long as it knows where it is [as with servos or starting from home]. i do not think it could work if you were in a move & zeroed the axis.
greg
ps i do not think servos would make a differance.

[ger21]

Actually, isn't it ±.009/ft? So in a 2 ft distance it could be off .018. Or, it could be perfect. depends on the specific screw that you're measuring.