c/cnc-operators

Found a stat about G-code usage that surprised me

Was reading through some old Machinery's Handbook I picked up at a garage sale last month. Turns out in 1980, only about 15% of shops even used G-code for their machines. Most guys were still running everything off cams and manual templates back then. It's crazy to think how far we've come in 40 years. Any of you older guys remember when shops first started switching over to CNC?

Showerthought: Buying cheap end mills vs quality ones

Picked up a 10-pack of $3 end mills off Amazon. First one snapped after 30 seconds on aluminum. Switched to a $18 single from a supplier I trust. Two hundred parts later and it's still cutting clean. Anyone else burn through cheap tooling then do the math on what you actually saved?

Got bold and tried a .005 finish pass on a finish op last Friday

Thought it would give me a mirror finish on 6061 aluminum but instead I got chatter marks that ruined the whole part. Learned real quick that sometimes too light of a cut lets the tool rub instead of cut. Has anyone else found a sweet spot for finish passes on softer metals?

Wasted $150 on fancy end mills I didn't even need

I bought a set of those coated carbide end mills for aluminum because the forum said they last longer. Turns out my old HSS bits cut just fine for what I do at my shop in Cleveland, and the carbide ones chipped on the first pass when I hit a clamp I forgot to move. Anyone else buy expensive tooling only to go back to the cheap stuff?

Finally stopped using coolant mist and switched to flood coolant last week

Been running a Haas VF-2 for 6 years and always fought with mist residue all over the enclosure, finally switched to flood with a $200 pump setup and the finish on some 6061 parts came out cleaner in one pass. Anyone else make the jump and see a big difference in tool life?

Mounted the tool holder on the wrong side of the gantry... or maybe the right side?

I set up my new ATC spindle with the tool rack on the left side of the gantry, thinking it'd keep chips from falling into the holders. But after a week of running parts in my shop in Phoenix, I keep bumping the rack into tall stock and losing all my tools. Which side do you guys mount your tool holders on to avoid this mess?

Last week I finally snapped on a guy for backplotting off my machine without asking

Been running CNC for about 8 years now, mostly at a shop in Cleveland. Last Thursday I walk over to my Okuma and this new kid is standing there with his phone taking video of the screen while it's doing a finish pass on a $4000 stainless part. I asked him what he was doing and he said "just grabbing the program real quick." I told him to back off and go ask the lead for permission first, because that's how people crash machines. He didn't even know what a tool offset was when I asked him about it. Has anyone else dealt with people trying to steal your code without even saying hey first?

Debate: Should you dial in feeds and speeds on the machine or on paper first?

Overheard two old timers arguing yesterday at a shop in Detroit, one swears by doing all the math on paper before touching the control while the other just tweaks everything on the fly at the machine. The paper guy said it saves him from scrapping parts and the on-the-fly guy said he gets done faster without overthinking it. Which side do you lean toward and has one way ever burned you?

Finally stopped crashing taps after 3 years of guessing

Last week I had a job running 304 stainless on a Haas VF-2, and I kept breaking M6 taps every 15 parts. I tried different speeds, peck cycles, even changed coolant mix. Then a guy from the shop next door told me to check my peck depth, turns out I was going way too deep per step. I cut it from 3mm to 1.5mm and ran 200 parts without a single snap. Has anyone else had a simple adjustment fix a problem you fought for months?

Was I wrong about coolant concentration for years? Here is what tipped me off.

I always ran my coolant at 8% because that is what the old timer who trained me said. Last Tuesday a rep from the chemical company came by and tested my sump. He showed me the refractometer reading 12% because water was evaporating faster than I thought. Now I am wondering if i have been wasting money on concentrate or if higher percentage actually protects better. Has anyone else had a sudden realization about how they mix their coolant?

Had a tool holder crash last Thursday that scared the heck out of me

I was running a batch of 304 stainless parts on a Haas VF-2 when my WIPS stopped reading mid cycle. The tool dove straight into the part at rapid speed and snapped a 1/2 inch carbide end mill clean off. Spent Friday reprogramming and adding a manual tool check step before every new run. Has anyone else found a better way to catch those probe glitches before they cost you inserts?

Been running CNC for 22 years and a simple G-code typo cost me 6 hours yesterday

Was machining a batch of 4140 brackets and forgot a decimal point, now I gotta scrap all 12 because the Z-axis went 0.12 instead of 0.12 and took a 3 inch cut instead of 0.12 inches, anyone else get burned by missing a period in their code?

TIL you can fix tool chatter by changing your feed rate instead of your speed

I was running a job on a HAAS VF-2 last week and this aluminum part kept giving me nasty chatter on the finish pass. Tried dropping the RPM like everyone says but it just made it worse. Then an old timer walking by said try bumping up the feed from 12 IPM to 18 IPM and it cleaned right up. Apparently the tool engagement angle changes just enough to stop the harmonics. Has anyone else had better luck playing with feed over speed for chatter issues?

Spent 45 minutes chasing a .005 inch offset on a Haas VF-2 yesterday

I was running a batch of 6061 parts and the finish pass came out looking like garbage. Turns out the coolant nozzle was aimed wrong and chips were recutting under the insert. Swapped to a high pressure nozzle and turned the feed down from 40 to 32 ipm and it cleaned right up. Anyone else ever get blindsided by something as dumb as chip evacuation?

Spent 4 hours chasing a 0.002 inch offset on a Haas VF-2 today

Turns out the coolant nozzle was nudged just enough to mess with the tool setter readings. Has anyone else been fooled by something that simple?

TIL a 0.001 offset can save a $200 part - found out the hard way last Tuesday

The old timer at my shop swore by 0.0002 offset for finishing passes on aluminum

I thought he was crazy because every manual I read said to use 0.001 minimum. Tried it his way on a job last week for a medical part, and that surface finish was the best I've ever gotten. No chatter, no tool marks. Proof that sometimes the guys with 30 years of work know more than the books lol. Anyone else got old timer advice that sounded wrong but worked?

The moment I realized I was crashing my end mills all wrong

I've been running this Haas VF-2 at work for two years and always babied my feeds on aluminum because I thought aggressive cuts would snap my tools. Last week I watched a guy on the next machine bury a 3/4" end mill at 200 IPM into a 6061 block and his tool came out like new. How do you figure out the real limits of your machine without blowing up a spindle or wrecking a $100 tool?

Showerthought: I spent a full shift chasing a chatter that wasn't there.

Had a job last month on an older VMC, making a simple aluminum bracket. The finish looked awful, like bad chatter. I checked the tool, the speeds, the holder, even the coolant mix. Spent about 6 hours on it. Turns out, the vise jaw had a tiny, almost invisible burr from a previous crash, so the part was vibrating ever so slightly. A five-minute file job fixed it. Has anyone else been fooled by something that simple?

I thought the whole 'tool presetter' thing was just shop floor fluff for way too long

Back when I was running a Bridgeport with manual tool changes, a guy from a big shop in Toledo told me to get one and I laughed. That was maybe 2012. Fast forward to last year, my boss got a used Zoller for our new VMC and I had to use it. First job was a 500-piece aluminum run with 12 tools. We hit size on the first part, every time. No touching off, no test cuts. It cut our setup time by over an hour. I still feel dumb for fighting it. Anyone else have a piece of tech they resisted that ended up saving their bacon?

TIL that old school coolant mix advice from a guy in Dayton was actually right

I always thought the 7% concentration rule for synthetic coolant was just shop lore, so I ran mine at 5% for years to save money. Last month I had a rash of rust issues on some 4140 steel parts after a weekend. Tried his exact mix and the parts came out clean after sitting for three days. Anyone else have a specific coolant ratio that works for tricky materials?

Vent: My brother-in-law, who runs a small fab shop, said 'a good operator just needs to push the green button'.

We argued for an hour, but him saying that made me realize how much our skill in reading the machine and adjusting on the fly gets overlooked. Anyone else feel like the real work happens after the cycle starts?

Finally got my tool change time under 30 seconds

I used to just let the machine run its full cycle, which took almost a minute for a tool change on our old Haas. About six months ago, I started tweaking the M-codes and pre-positioning the next tool during the cut. The change was small, but over a 500-part run last week, it saved us over four hours. Anyone else mess with their machine's macros to shave off a few seconds?

Hot take: I thought coolant concentration didn't matter that much

My boss made me track tool life on a specific aluminum job for a month. After bumping the mix from 5% to 8%, the end mills lasted almost 30% longer. Anyone have a different sweet spot for 6061?

Heard a shop owner say he pays more for a clean machine than a fast one

I was at the local supply house in Akron and overheard two guys talking. One, who runs a 15 man shop, said he'd rather hire an operator who keeps their work area spotless than one who can shave ten seconds off a cycle time. He said a messy station costs him more in tool damage and scrap over a year than slow cycles. I always thought speed was king, but his math made me stop. Do you guys think a clean machine habit is really that big of a deal for hiring?