Funny, but a lot of newer CAD packages do not provide ASME or ANSI standard symbols in their default settings. Some cannot be customized to provide them, either. Part of the general shift towards sloppiness I have been seeing in this business for years. You certainly have a surface finish callout there, albeit a poor effort at one. These guys are right, too, in that 250 RHR can be achieved on the bandsaw. I won't even call them out when they are that rough unless, for some reason, it has to be that rough. That's seldom the case. Most applications I deal with are "or better" finishes, with the callout being the minumum acceptable finish.

It really defeats the object of having a standard if people won't/can't use them doesn't it?

While I can see that the INTENT may be for that marking to be a surface finish it isn't the accepted standard for a surface finish, so I would suggest the draughtsman would be better off just putting a note saying "Surface finish on ends of tube to be...." and eliminate the ambiguity.

I don't know if that's a surface mark. Looks more like a wall thickness value based on the ID and OD of the part. If it was a surface finish, the value would be a range, say "50-250 microinches." Even if it's a wall thickness, it's a poor method of indicating it.

Then again, I deal with large pipe and we don't particularly care so much about the finish of the cut, since we bevel and weld the ends together anyhow. 1.125" pipe/tube with 0.250" wall thickness is pretty hefty.

I rarely see drawings with indicated dimensions or surface finish that didn't have a unit of measure on it. I sure as hell try not to let something like that happen.....

It can't be a wall thickness as with an ID of an inch and and OD of and inch and a quater the wall would be an eigth.

Yep, wall is .125"

Yup! serves me right for typing on the BBS while working....and looking at piss poor drafting work! (sorry, I've been screaming at drafters the last few weeks to get ***** done....and correctly)

Jeff, this surprises me. Even my almost decade old copy of CADKEY 98 has these symbols available. Are you talking about low cost "consumer" CAD systems, or software that actual engineers would use?

Len, I really hope yours is the winning bid. (Can you actually find tubing/pipe with those OD/ID dimensional callouts, or will one or both diameters need to be turned? I don't have any of my material catalogs in front of me.)

Good luck,
Jim

Once again, it IS a finish mark and I and others have used that exact mark on mechanical drawings. I deal with drawings from many different industries including automotive and I have seen that often. another mark that is ocasionally used is one that looks kind of like an f hole on a violin only with sharp corners.

I'll agree with the others. It is surface roughness. It is a piss poor surface texture symbol, but commonly used. And it does mean 250 microinches, which is about the middle of the range of band saw cuts, so it means use a sharp blade with the right size teeth.

Yup...surface finish and he's going to seal on the end of the tube, so like Anton said don't hack it to length with a crap blade.

Just being pedantic, but what standard is that then?

Thanks Jim, and yes that's a very common size tube in either DOM or electric weld though the I.D./O.D. tolerances make DOM (Drawn Over Mandrel) the obvious choice.

Regarding end finish, we use cold saws and/or our orbital shear, both of which produce an excellent end finish, much superior to that of a high speed lathe cut-off.

I'm wondering now if this tube is involved in the pneumatic height adjustment and may actually need that soft seal. I'll find out today either way and post here if only for entertainment purposes. Thanks again guys.

I'm a mechanical engineer for a utility machine shop. We mainly repair turbines and pumps, but our main value comes when we have to reverse engineer a part that hasn't been made for many years and/or the lead time from the OEM is too long. Sometimes the OEM's even give us the original drawings if they know they can't fabricate the part as fast as we can.

It's probably not as interesting as designing new stuff like you do, but it's still pretty fun and it gives me access to machine tools to make Porsche parts and other racing stuff :D.