Machsupport Forum

General CNC Chat => Show"N"Tell ( Your Machines) => Topic started by: CNCexplorer on March 25, 2012, 06:44:42 PM

Title: Upgrading to linear bearing system advise!!!!!!
Post by: CNCexplorer on March 25, 2012, 06:44:42 PM: I am planing on switching to linear bearing system from aluminum angle/ball bearings. I am only planing to convert the y and z axis and the dimentions are about y=30"/z=12" more or less. :)

So i am planing on buying the aluminum round rod and bearing block separate. I think i am gonna go with 12mm or 16mm system as they seem to be the cheapest.

this link shows a 12mm aluminum rod and bearing shaft system pre installed very expensive though :o
http://www.ebay.com/itm/CNC-Router-Table-XYZ-Linear-Motion-System-XY-Bearings-/130182318463?pt=LH_DefaultDomain_0&hash=item1e4f78897f#ht_911wt_906

BUT

Q- Will a 16mm bearing block and 15.875mm aluminum rod work and fit fine? :-\

http://www.ebay.com/itm/SBR16UU-16mm-Open-Linear-Bearing-Slide-Linear-Motion-/120780617175?pt=LH_DefaultDomain_0&hash=item1c1f15f5d7#ht_2456wt_1039

http://www.ebay.com/itm/5-8-625-Aluminum-6061-Round-Bar-Rod-12-Length-/180798484595?pt=LH_DefaultDomain_0&hash=item2a186df073#ht_917wt_1039

These aluminum rod are way cheaper that the other onces that comes in a set. Only different is the supplier only have rod in these dimensions
aluminum rod 9.525mm,12.7mm, 15.875mm,19.05mm, 20.624mm, 22.225mm

bearing blocks 12mm, 15mm, 16mm, 19mm, 20mm, 22mm

So my best bet seems like the 15.875 aluminum round rod and 16mm bearing block (did i got that right)

Q- which one of these above combination would work the best or any other ideas?

have a wonderful day :)
Title: Re: Upgrading to linear bearing system advise!!!!!!
Post by: ostie01 on March 25, 2012, 07:31:10 PM: Hi, I think this not a good idea to use alu rod with linear bearing.

The steel rod is hardened and it need to be.

You will spend money ant time with the aluminum rod and it will not do the job correctly.

And aluminum is very expensive too so don't think this will make a huge difference at the end.

Jeff
Title: Re: Upgrading to linear bearing system advise!!!!!!
Post by: Sam on March 25, 2012, 07:33:43 PM: Quote
Q- Will a 16mm bearing block and 15.875mm aluminum rod work and fit fine?
No. Not at all.

I would try here for your needs.... http://www.pbxbearings.com/

If you need the shafts cut to a particular length, you will have to have a thin grinding wheel, a die grinder or chop-saw, safety glasses, and some common sense.
Title: Re: Upgrading to linear bearing system advise!!!!!!
Post by: CNCexplorer on March 25, 2012, 07:55:21 PM: Quote
Q- Will a 16mm bearing block and 15.875mm aluminum rod work and fit fine?
No. Not at all.

So if i buy a 16mm bearing block and a 16mm steal or aluminum rod would that work/ fit together fine? (buy them separately not as a set )
Title: Re: Upgrading to linear bearing system advise!!!!!!
Post by: Sam on March 25, 2012, 10:05:45 PM: No. As Jeff stated, you cannot use aluminum rods. The ball bearings would eat into the aluminum in no time, leaving you with a gummed up, non moving, or sloppy moving, pile of useless junk. Besides that, the aluminum rods(or regular steel rods, even) are not fabricated to a precision diameter. You need to purchase precision, hardened shafts. You can buy shafts from one vendor, and the bearings from another, if you needed to do that. They do not have to be a "matched set" or anything like that. 16mm rods purchased from one vendor should fit 16mm bearings from any other vendor.