PDA

View Full Version : A good source for ballscrews?



phantomcow2
09-12-2005, 06:26 AM
I would like to try ballscrews for my Z axis to see how I like it, but i am only finding two sources of ballscrews;
Ebay
McMaster Carr

Are there any other sources out there I am missing? I am looking for a regular format online store

KSky
09-12-2005, 09:49 AM
Try Rockford Ball Screw company. I have not ordered from them yet, so I would be
interested in feedback from people who have.

http://www.rockfordballscrew.com/about.htm

miljnor
09-12-2005, 11:23 AM
www.roton.com

They are cheaper than mcmaster carr but make it up in shipping. but the product is far superior to the Mcmaster stuff.

Roton ballscrews are ground and give a much smoother action. If you have a problem turning hardend material I would go with mcmaster as there ballscrew is only surfaced hardend and after you break thru the initial layer, cuts like butter.

Willyb
09-12-2005, 12:56 PM
Ebay is a good place to pick up ball screws if you do some home work. You can usally find good ground P4 screws with zero backlash nuts for less than what you would pay for new rolled units. I pickup three good ones for my mill conversion.

Bill

phantomcow2
09-12-2005, 01:30 PM
I check on ebay and most of the auctions (last time i checked under ball screw there were 23 auctions) are much higher end than I need or want.
As for Roton, I was on their website, what do they usually charge?
When i get home I will request a quote. It would be nice to have an online catalog...
Thanks for the replies all!

miljnor
09-12-2005, 02:08 PM
origing is phantomcow2
As for Roton, I was on their website, what do they usually charge?

don't quote me but the ballscrews (5/8 smaller of the two) are 17.00ea you need two per axis if your making an anti-backlash nut. and I think the screw is somthing like .97c an inch or close to it. the prices are similar to mcmaster once shipping is add in but like I said the quality is MUCH higher than the mcmaster stuff.

pcroxford
09-12-2005, 03:28 PM
just out of curiosity, why not use threaded rod?

ViperTX
09-12-2005, 03:30 PM
Ah miljnor....Roton's ballscrews are "roll formed" they are not ground. I don't see why you state that they are more accurate then the McMaster?

phantomcow2
09-12-2005, 04:04 PM
Ah miljnor....Roton's ballscrews are "roll formed" they are not ground. I don't see why you state that they are more accurate then the McMaster?
Do you know if the McMaster screws are ground?
I am just curious, i dont think it would make a difference for my mill with not a lot of travel

timlkallam
09-12-2005, 04:38 PM
Try THK website I have an account with them if you see what you need I can look up the price for you. https://www.tos-world.com/webapp/wcs/stores/servlet/StoreCatalogDisplay?catalogId=10051&storeId=10001&langId=-1&msgFlg=Y

ViperTX
09-12-2005, 05:10 PM
McMaster-Carr ballscrews are rolled.

miljnor
09-12-2005, 05:17 PM
by ViperTX
Ah miljnor....Roton's ballscrews are "roll formed" they are not ground. I don't see why you state that they are more accurate then the McMaster?

Sorry! I misspoke myself I was thinking of another manufacture that I was looking at previously. I think I got confused when the ballscrews showed up, The ones from Roton are far and away nicer looking and sparkly that I forgot myself. :D I would still recomend the Roton over the McMaster stuff just on the material toughness. The Mcmaster stuff I have cut realy easily on the 7x9 HF lathe I have at home but the Roton stuff I had to do at work do to the hardness (kept blowing up my bits, probably do to lack of ridgitity at home).

Sometimes the fit and finish makes the diference between good and bad.

phantomcow2
09-12-2005, 05:26 PM
Wow, I called Roton, they are really nice people! I explained i was hobbyist and what i am after, they recommended the 5/8 dia .200 lead stuff at 8 dollars and something cents per foot. That is a pretty good price difference compared to McMaster.
My concern is that I will have to machine the stuff, he said you can heat the part you want to machine until its cherry red (keeping the part you dont want to machine in water), and that this will get rid of the hardening to make it easier to lathe.
I called up Rockford ballscrew and I guess they close at 4 so I am out of luck for today

phantomcow2
09-12-2005, 05:33 PM
There is one thing i am unclear about i forgot to ask
The guy at Roton said that the ballnuts are not preloaded (which takes up backlash I believe, correct?), but he said for a 10$ fee they will pack the ballnuts with larger ball bearings, is this to take up the lash? Can somebody explain this further

miljnor
09-12-2005, 05:39 PM
yes this takes up the backlash by removing all of the freeplay in the ball screw. Don't know the specifics but I have actually done this myself (do to a accidental spilling of the normal balls, don't remove the cardboard! :) ) Bigger balls removes all of you freeplay thus taking up all the backlash (and of course the chick dig you more :0 ).

Another way to do it is to buy two ballscrew and load them against each other with some form of tenssioner, but it is more expensive to do it this way.

Willyb
09-12-2005, 05:48 PM
The balls that are circulating inside the ball nut are replaced with slightly larger diameter ones to take up any clearance between the screw and the ball nut threads. This will likely make the ball nut a little harder to spin on certain sections of the screw until things wear in. Only problem with this method is that it will eventually loosen up as things wear.
If you go with two nuts, you can always adjust the backlash as the items wear.

Willyb

ViperTX
09-12-2005, 06:12 PM
Willyb is correct...but if you wear out a ballscrew or a nut in your home shop....I would say you've so much business that you'll be able to afford a new machine! Well, unless you deliberately abuse it.....

phantomcow2
09-12-2005, 06:35 PM
eeh going with 2 nuts is expensive.
I think I will pay the extra 10 though to get the bigger bearings. I doubt I will wear the ballnuts on my micro mill...
speaking of, is it possible to replace the bearings in the ballnuts if they eventually wear out?

Willyb
09-12-2005, 06:37 PM
Yes, "ViperTX" is correct that you are not likely going to wear out a ball screw with hobby use. It's just allot easier to re-adjust the ball nuts on the machine rather than having to remove the complete screw assembly to replace the balls. Just my opinion.

Willyb

ViperTX
09-12-2005, 07:11 PM
When I ordered the McMaster-Carr 5/8 in ballscrews (2 each 36 inches long) and 2 Square Ballnuts and the oversize ballbearings the total was about $110. I have to load the ballbearing myself.

Willyb
09-12-2005, 08:01 PM
:-)

phantomcow2
09-13-2005, 06:19 AM
So when you have two nuts, how does this work to prevent lash? Do you push away from eachother with a spring so that they are constantly contacting the screw?

ViperTX
09-13-2005, 10:08 AM
Yes, that is how you preload the ballscrew nuts.