Sources for Cheap Miniature Ball Screws?

I've been looking through the interweb and found a few nice miniature ball
screw assemblies from the likes of Bosch-Rexroth, NSK, and Specialty
Motions Inc, but I'm not sure what the next step would be, or even if
they're affordable for the average hobbyist like me.
On Monday I'm going to start calling some local distributors to see what
the process is of getting some prices.
So far the only item that I've found with a price is a miniature ball
screw assembly at McMaster-Carr which goes for $150 each, which is really
out of my price range.
Do cheap miniature ball screws exist?
Thanks!
Alan
gestaltUNDERSCORE73ATyahooDOTcom
Reply to
Alan Timm
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IMO you either watch eBay or use the 5/8" diameter by .2" pitch cheapy from
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Reply to
Robin G Hewitt
Sorry wrong link, try the distributor
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Reply to
Robin G Hewitt
Keep your hopes up. McMaster-Carr sells things for 4 times more than anybody else. I think they stay in business since their selection is so good.
BRW
Reply to
Bennet Williams
For cheaper than $150 you're going to need to go surplus. By their nature reciprocating ball screws are precision mechanics, and that's where the price comes in.
Does your application absolutely require ball screws? Would a lead screw work as well? They make fairly affordable anti-backlash lead screw assemblies in all varieties of sizes. McMaster-Carr is one source; I prefer Reid Tool & Supply.
-- Gordon Author: Robot Builder's Bonanza Budget Robotics:
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Alan Timm wrote:
Reply to
Gordon McComb
Hello!
Firstly thank you all for your help and suggestions.
To recap:
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- sources of ball screws
Miniature Ball Screw Assemblies will run about $150-$170
5/8" ball screws and ball nuts are a from 1/5 to 1/10 the price of other sizes 5/8" ball nuts are between $20-$30 each 5/8" ball screws are about 1/2 the cost of other sizes
mcmaster stocks a 3/8" ball nut for $60 which passes for miniature mcmaster stocks 3/8" ball screw material for $1.79 per inch.
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Robin G Hewitt: Thanks for your tip about MSC Industrial. I've been looking through their catalog and verified that there is a specific size ball nut that sells for 1/5 to 1/10 the prices of the others in MSC and McMaster. I'm thinking strongly about adapting my design around that specific size. I also noticed that McMaster stocks a 3/8 inch ball nut for $60 that has the approximate proportions of a "miniature" ball screw.
Gordon McComb: Yeah, I've pretty much come to the same conclusion that the Miniature Ball Screw assemblies are going to be in the $150 range, but luckily I've found a 3/8" ball nut and screw in McMaster-Carr @ $60 per nut. It's still more than I'd like to pay, but it's definitely better than $150.
I've been trying to recreate a "poor-mans" version of MIT's frameless linear actuator. I built my first prototype with a lead screw, and I'm losing most of my torque to friction. Everything I've seen so far suggests that peak efficiency of a lead screw is only %20-%30 effecient, and ballscrews should be about %90 percent efficient, which suggests about 3x the force output. So for prototype #2 I'm going to try a ball screw and pay closer attention to sources of friction.
Thanks!
Alan
Reply to
Alan Timm
Try
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-- that's about my favorite place for this stuff.
Reply to
E. Lee Dickinson
Robin's catch of #28 for a 5/8" ballscrew is a good one, though frankly I can't fathom why that size and pitch is SO much less than the others. I guess it's not a typo. Maybe as 5/8" is so common for small machines they make so many they can afford the volume discount. 3/8" is a bit more compact than 5/8", though that isn't quite as "miniature" as I was imagining!
I would think that in addition to the screw mechanism a fairly hefty source of friction is the guide (or guides). I would agree that a *quality* ballscrew would be important, but the linear bearings and absolute precision in construction would be too.
Let us know how this thing works out for you!
-- Gordon Author: Robot Builder's Bonanza Budget Robotics:
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Alan Timm wrote:
Reply to
Gordon McComb

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