Drill Hole Dimensions on prints

I think SW answer would be that ANSI says to use the decimal callout.

One of the problems with cranky machinists is that there is no standardization. It is very unusual to find two cranky machinists who will agree on everything. No excuse, just an observation. Software should be able to accommodate cranky machinists as well just for diversity's sake. Now I suppose a macro could be written to go through dims on a print and replace the value with letter drill sizes. Or you could do this manually.

You could buy your cranky machinist one of those charts that shows decimal to drill size conversion. A lot of suppliers will give you one for free or you can download it. Your shop probably has one hanging up already.

When I got my journeyman's machinist card more than 20 odd years ago any machinist worth the title kept his Starrett drill card close at hand.

. We have some old' ;) cranky

I don't know the answer to your question, but I do know some things about cranky old machinists. I agree with Paul and the other poster in that it's impossible to satisfy every individual one of these types because they never agree. I also agree that any old school guy worth his salt knows all that stuff in his sleep.

More likely he's just screwing with your head. That's a favorite past time. On the other hand, I have learned a lot from the `old-school' types as well. Always pay attention to what they say and then go back to your computer and think about how to implement what they want in a way that makes sense in today's world. (sounds like that's already what you're trying to do) You'll never stop hearing the griping, but you will pick up some tricks.

I know a lot of cranky young machinists as well. These are the dudes who say they can design an entire mold using only surfaces-then laugh at you in a superior way when nobody but them can understand what the hell they did.

Good Luck,

jk

For drilled fractional holes: clt-select those dimensions you wish to modify, right click and select properties, then clear the checkbox that says "use document units", hit the units button, select fractional, make the denomenator 64, and hit the round to nearest fraction button.

This also holds true for tapped holes larger than 1/2-13. For smaller tapped holes I usually leave the drill diameter off of the print. Smaller holes often have different pilot holes, depending on the drill chart/tap type/tap mfg/material ect. Leaving it off the print makes the machinist take those variables into account rather than blindly following the drawing. I'd rather rely on experience than on what SW determines to be the proper hole diameter.

All of our drill indexes have the decimal equivelant stamped into them. We also have 2 2'x4' signs with metric/english conversions and all common tap pilot holes prominately displayed in our machine shop.

We went thru the calloutformat.txt file and added an extra line to all of our calllouts. This extra line is to display the Hole Wizard description. Give it a try.

Ken

Well, I'm a cranky old machinist with another twist for you guys. I tell my people NOT to memorize anything. There's plenty of reference material laying around here for anything that's not properly called out on the print. Too much of a chance for the machinists temporarily faulty memory convincing the memory of the checker he's right.

Oh, yeah!! You betcha!! I don't hold to jb's cranky machinist, though. He's just being an ass. I wouldn't accommodate him.

Excellent, excellent advice.

McQ

Every machinist I worked with (including myself) probably would have found it downright humiliating to have to ask "What size drill is this?". A sure way to call one's lack of competence to attention.

Machine OPERATORS, maybe, but a machinIST is a craftsman, and knows where to find out (most often from memory).

Well..... Thanks for the feed back.. Let me first fess-up as I am the cranky old machinist, but I also have spent some time doing design work. I/we do tend to screw with the new guy's... we have a newer design engineer in house trained on most other software not SW. Doing great work... but ... well I do have to 'teach' him something..

When I was brought up though the training 'machinist' in the 70's and 80's it was "Always follow the Print" no matter what you might think or think you know.. So when a hole 'on print' says .234 I think .234. not .234 +-. 005 or

+-.015.. Now on the other hand a callout of 'A' drill will give you the tolerance needed to use an A drill..

Yes most of the tap drill sizes are in my head... though some don't like to shake out to fast any more.. note to the draftsman{oops designer/engineer}. If you want a specific class thread put in on the print.. most of the taps on hand are 2b.. ;P

Thanks Tin Man this might be what we were looking for.

jb..

I feel sorry for you lot, still working away with decimal inches, which can't easily be related to anything much in the real world, because you were all brought up on fractions. Here in the rest of the world, we are still waiting for you to catch up so we don't have to dual dimension everything.

Sigh...

Are you talking about that little mm the engineer keeps putting on all my prints? I've been waiting to go to them since around 1977 or so.. Been so long I can't even remember when the 'gov' said we all would make the conversion in five years...

jb..

jb,

Make sure you look at what other variables you can use from the Hole Wizard too. To see what I mean, go to one of your Hole Callouts in a drawing file:

-RMB the callout

-Choose (Dimension) Properties

-Click Modify Text (button at the bottom)

-Now click the Hole Variable button at the right. If this button is

*not* enabled, then that means that the callout is not on a standard Hole Wizard created hoile.

Maybe one of these would possibly be better than the Hole Description. Ken

The gummint isn't going to force the conversion. It'll happen when the last American manufacturer is bought by a foreign investor. :)

aw