How many people have used 5/16 rods? would LM5/16 be worth it.

I am talking to a manufacturer of LM8UU bearings and I was wondering if there would be sufficent interest to warrant a small production run of linear bearings for 5/16 rods. as well all know using lm8uu with 5/16 rods can cause more problems than it is worth and people usually upgrade there rods to precision ground 8mm as well.
So I was wondering if there would be an interest. folks let me know
terramir

I know getting metric stuff can be a pain when you're in the US, but we really just need to let imperial die. The more metric we buy, the quicker manufactures will switch over their production lines.

I think it's cheaper and easier to just go with metric parts to start with. With metric, you can be reasonably sure that if someone posts an upgrade on thingiverse or the wiki, you probably have compatible parts, or can get them with only a marginal effort. Reprap is a very international effort, and inevitably many upgrades will use metric parts.

You can't get much metric at your local home center in the US but McMaster carr supplies it. 8mm and 5/16" are pretty close is LU8MM too loose on 5/16"? 'Loose' like it actually affects performance, or is this just being picky?

Having grown up in a world with feet & inch we have come a long way. Most cars are now metric, I think. Most manufactures are designing in metric. unfortunately their operators are most likely to use inch base equipment. The areas that won't ever change is construction and our highway system.

I'm doing my part, everying I design to and build is in metric. I just can't seem to find a good metric tape measure... I guess that supports my comment about construction.

In the US for metric tape measures, other than McMaster, try Fastenal, Rockler or Lee Valley.

This is a bit off topic but I've always used Stanley tape measures. on a quick internet search of US companies like McMaster Carr they do not sell a pure metric tape. Everything is inch/mm. They do have a metric only in a lufkin brand. I guess there is simply no precieved market for a metric only tape in the US. I stopped in a Rockler store lately and same story.

I find tape measures with both metric and inches at times but yes a tape measure tends to be a us thing anyway, rulers meter sticks and those windup rolls with the nylon with meters deci meters and centimeters printed on it kind of tape is more the world's style. our metal that's a little curved tends to be a US thing all together I tried to find one when I was living in germany 20 years ago no dice. they had flimsy thin and flat metal though.
Yeah well I'll be upgrading to •mm rods soon but as of right now I need to stick with what I got right now producing the bar clamps out of wood lol, then I get to make the z-motor mounts that's gonna be loads of fun lol
hope to be done with the strap build by march 1st then order the "ink" ABS and first thing I'll print is a set to rebuild prusa strap into a proper prusa mendel lol.
terramir
PS so obviously people think it's a bad idea okies consider this thread closed

Edited 1 time(s). Last edit at 02/16/2012 09:15PM by terramir.

There are enough places to get 8mm rods/bearings online in the US, either ebay or vxb.

5/16 bearings are far less common and generally more expensive than 8mm, even including shipping.

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www.Fablicator.com

LM8UU bearings do not work on 5/16" rod. I believe it is because the ball bearings do not properly engage the rod, they just kind of slide around. I've tried it, it's noisy and vibrates a lot.

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Makes sense since 5/16 is 62 microns smaller then the inside of the bearing, which is a significant amount of clearance for a bearing, especially if it were important to have stiffness in all radial directions. So sliding up and down would be sloppy, but how about loading in one direction like in the case of the Y axis - extruder?

Hi All:

Please check the BOM in my Mendel variant "Simplified Ball Bearing Mendel" for a cheap M8 oil hardening ground drill rod. I use this rod (from Enco 505-0240) in all my builds, it is straight, smooth and cheap at 4.59 for 3'. Check the machinists BBS for the perennial Enco free shipping offers....

j

btw just an update if you buy your drill rods from home depot and they are the crown kind if you bring your caliper you will find drill rods that say 5/16 but there really 8mm. Just to let you know
terramir