[acncguy]

Hi,

I was wondering if anyone uses gage cuts for finish boring operations (about +/- .002" or less) or gage cuts for centering machining to castings or weldments, or for any other reason. Management 'found out' we use gage cuts and because it adds some cycle time - they are constantly asking why and generally think we don't need them. We machine from about 200 lbs - 1,000 lb (most of our work) to 10,000 lbs ductile iron castings and large steel weldments on horizontal machining centers and boring mills. We use gage cuts if probing won't reach...

SoOoOo...I would like anyone's general thoughts on gage cuts. Good? Bad? When necessary, when unnecessary? We also take gage cuts if holding close depths and using two different tools to do so...

Thanks for any input.

[diyengineer]

"management disagrees"

Why would it be up to management and not the machinist? If you are making parts within tolerance, why would it matter what you choose.

[cweston]

If you are satisfied with the quality, I'm sure you justify your decisions.

[acncguy]

Because of time. Time is money, and they see this as a waste of time (unnecessary). I say you save more in less scrap than you do eliminating the gage cuts.

I'm just wondering is this SOP anywhere else, and for what reason. You say "gage cut" to management now at the shop I work for and it's viewed upon so negatively - it's starting to make me look bad in the eyes of management. Given the size of our work and the repeatability of the castings, also the length of our cycle times, I say it's well worth putting these 'safeties' in place to help ensure a good part.

Like I said, work is being done on HMC's with CAT 50 spindles. The reason we use them is #1 we get over sized-bores once in a while so we take gage cuts (just cut a small percentage of the bore length) so if it's over size a couple thousandths for that length, it can be adjusted and still make a good part. I understand "theory", but reality and theory are two different things.

#2 Also to help align castings to the machining & #3 to hold close depths if using more than one tool (one tool mills the face, the other mills the bottom of a bore or something - we would hold the Z plus .005" or .010" and measure where we were before taking the final cut.

Anyway what can I do here? I really don't have the time to do some lengthy study that somehow 'proves' my point, but whatever. I'll take any thoughts on this.

Thanks.

[gmfoster]

Because of time. Time is money, and they see this as a waste of time (unnecessary). I say you save more in less scrap than you do eliminating the gage cuts.

I'm just wondering is this SOP anywhere else, and for what reason. You say "gage cut" to management now at the shop I work for and it's viewed upon so negatively - it's starting to make me look bad in the eyes of management. Given the size of our work and the repeatability of the castings, also the length of our cycle times, I say it's well worth putting these 'safeties' in place to help ensure a good part.

Like I said, work is being done on HMC's with CAT 50 spindles. The reason we use them is #1 we get over sized-bores once in a while so we take gage cuts (just cut a small percentage of the bore length) so if it's over size a couple thousandths for that length, it can be adjusted and still make a good part. I understand "theory", but reality and theory are two different things.

#2 Also to help align castings to the machining & #3 to hold close depths if using more than one tool (one tool mills the face, the other mills the bottom of a bore or something - we would hold the Z plus .005" or .010" and measure where we were before taking the final cut.

Anyway what can I do here? I really don't have the time to do some lengthy study that somehow 'proves' my point, but whatever. I'll take any thoughts on this.

Thanks.

Well the sad thing is you do what management wants. If it works they look good, if it doesn't work then you look bad. Same reason that a company Like Hostess Twinkies gives management 80 percent pay raises and blames workers for going broke. You can try and document that you are against it so if/when it doesn't work you have some defense. Sadly they will likely say you are just a poor machinist and caused the problem. It took me 33 years to learn, but as a worker bee our job is to do what the boss wants. Trouble is often they have no idea what they really want except to line their pockets.

[lancut]

Tell them, it cost more to do it RIGHT the second time..

[dertsap]

Anyway what can I do here?

.

been there done that , some places bring in more work than what can be accomplished . It's a shame to ruin a part that is worth tens or hundreds of thousand dollars because someone doesn't want to go thru that one extra safe step .
The way I see it is simple , I get paid to do what I'm told to do , so under those types of circumstances my best solution has always been to let management know that I'll do exactly as they ask , as long as they are willing to exempt me from any responsibility if a part is scraped because of the lack of due care and attention . Maybe if the responsibility shifts toward them then they'll begin to see things your way , otherwise be sure to have a witness
.

[txcncman]

Two things:

1) Get their instructions (not their questions to you) in writing with their name(s) attached.

2) Step away from the machine and tell them, "Show me how."

If your casting suppliers are guarantying their accuracy, you should be able to do away with gage cuts or test cuts. Once a piece is positioned properly to the designed datums and does not clean up after machining, your company can "charge back" to the supplier. In other words, trash in, trash out - quality in, quality out.

[christinandavid]

Whatever you do, don't perform a test-cut then proceed to make an incorrect adjustment

DP

[fizzissist]

Two things:

1) Get their instructions (not their questions to you) in writing with their name(s) attached.

2) Step away from the machine and tell them, "Show me how."

If your casting suppliers are guarantying their accuracy, you should be able to do away with gage cuts or test cuts. Once a piece is positioned properly to the designed datums and does not clean up after machining, your company can "charge back" to the supplier. In other words, trash in, trash out - quality in, quality out.

I'd emphasize 1)
I've found that 2) generally just pisses them off, since they obviously know nothing of the process in the first place.

... Do these same managers take their kids to the doctor and say skip the tests, just treat the kid?? We'll find out later if it was the wrong treatment....

[fizzissist]

You might consider asking management to put this in writing as a SOP... since it's such a good idea to forego a precautionary and calibrating step.
..... Couched in terms, of course, that make it sound like it's their idea.

Management hates it when the peasants come up with good ideas....