bright mild or stainless rod

[rosinante]

Hi all ,might be a daft question but how "round" is bright /ss rod nominal dia 16 mm will be good enough to run in bronze bushes without further machining? I know ground stock is available but outside my budget as are linear bearings, I m making an xy table that's lever operated
thanks in advance
Chris

 

[dan.taylor.1]

Bright is fairly round, stainless no idea, Ge only bits I've had were small from eBay and were spot on round but whether they come like that or its been lathed I don't know.

Dan

 

[printcom]

I have to take 1mm ish off of a piece of 50mm bright in the lathe to get it right, bear in mind this includes the variations of my 3 jaw chuck.

 

[brightspark]

I have to take 1mm ish off of a piece of 50mm bright in the lathe to get it right, bear in mind this includes the variations of my 3 jaw chuck.

if the chuck is slightly out clock the job with a dti gauge and pack one jaw with cigarette paper till corrected

 

[hotrodder]

A 13" length of 16mm silver steel should be less than a tenner...
Tolerances for bright steels here... http://www.bright-steels.com/section1.html (seperate link at bottom of page for straightness)

 

[rosinante]

roundness

Thanks for replies fellas,Hotrodder the table suggests the BMS would be ok for my needs,--x y table for a slot morticer, cheers
Chris

 

[scott0031]

Just a word of warning, the specified tolerance in that table are not good for any form of bearing. It can be pretty much up to 3 thou down on size 3 thou is a hell of a lot. The problem with mild and all bright steel is they generally are not that round, in this case can mean you could measure one point and be dead on 16mm turn 120 deg and it could well be 15.93mm having this sort of ovality is not uncommon for bright non ground steel bars. Its is pot luck as some can be good others not so good. If you can go and check some material before you buy that's preferable than buying blind.

Stainless on the other hand is round, again there will be working tolerances, and everything I seem to get supplied with is generally a tad down by .01 to .02 mm but is is round.

Looking at what you are doing its a low end application really but it wont be a lot of use starting with something that's bad to begin with, it will only get worse.

I will probably have some mild on the shelf and i know I have some stainless 303 as i just used some for a job. Pending how much you want, i may have some.



Kind regards,


Scott

 

[rosinante]

Hi Scott , I have some 16mm stainless but need about 600mm more
[or 2 x 300mm lengths] I have found some flanged bushes on the bay to suit and the rest will probably made from hardwood,as you said it is a low end project to see if it works really,I have seen linear bearings but I am worried that they will clog with dust etc,if it works then I will consider a rebuild out of metal, I have lots of woodwork kit but limited to a grinder , welder and pillar drill for the metal side,how many beer tokens would you want for 600mm ?
Cheers
Chris