DOM Pipe Straightness, runout. 1

[mechantaeus]

Does anybody know how straight are carbon steel DOM Pipes. i am working towards cost reduction of roller manufacture.
The pipe i am looking at is 8"OD 87 " long (ryerson pg 210),
i need to EPDM coat this roller such that the final circulat runout is .008".
What I dont know is how straight are these pipes to begin with?
Thanks,

Work Hard and Work Smart

 

[ctopher]

Don't know. I can not find this info. Best bet may be to call the manufacturer of the pipe.

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP0.1 / PDMWorks 05
ctopher's home site

 

[CESSNA1]

MECHANTAEUS: The toleranaces should be in the Ryerson manual. If not they are in the AISC manual. Or as CTOPHER says, call the manufacturer/supplier

Regards
Dave

 

[Cockroach]

Allowances for clean up for seamless mechanical steel tubing, drawn over mandrel intended for machined to size are as follows:

1) 3/32 < OD = 0.008 on OD & ID,
2) 3/32 < OD <= 3/16 = 0.012 on OD & D,
3) 3/16 < OD <= 1/2 = 0.015 on OD & ID,
4) 1/2 < OD <= 1 1/2 = 0.020 on OD & ID,
5) 1 1/2 < OD <= 3 = 0.040 on OD & ID,
6) 3 < OD <= 5 1/2 = 0.060 on OD & ID,
7) 5 1/2 < OD <= 8 = 0.080 on OD & ID.

For sizes greater than 8.0 inch OD, machinining allowances are mutually agreed upon by the purchaser and manufacturer.

When tubing is finished to size by grinding rather than machining, the clean up grinding allowances are:

8) 3/32 < OD = 0.005 on OD & ID,
9) 3/32 < OD <= 3/16 = 0.006 on OD & D,
10) 3/16 < OD <= 1/2 = 0.008 on OD & ID.

These values are typical across the industry in North America. I don't have the German allowances, but they are approximately equal. The Japanese allowances are somewhat better, slightly under these indicated values.

Hope this helps.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[nnjunger]

You may want to watch that handling of the tubing doesn't cause you more problems than the actual machining variance of the rolls. I have found that with both DOM and even solid shafting material. Sometimes the truck drivers can cause enough damage that the machine shop can not get the material back into spec.

 

[mechantaeus]

Thanks for all your answers. The tolerance on the DOM was acceptable because we are getting it EPDM coating that can compensate a lot )

Regards,

Work Hard and Work Smart