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  1. G

    Milling V-groove with chamfer mill. Disaster or success?

    HSS drill-mill. I rough with a small EM or even BEM first. Then as many passes as needed to get surface finish. You will always get a flat on the bottom, how big depends on the tool grind. I cheat and do a step over in the XY and climb cut both sides, or the conventional side of the slot...
  2. G

    Milling a half circle

    Dang it, I saw a guy making hemispheres using an annular cutter while rotating the part on a 5-axis. It was slicker than snot. I was going to go back and figure it out… but I got sidetracked. Now it’s just a hazy memory. Sent from my iPhone using Tapatalk
  3. G

    Instructor approves cutting steel at 2000sfm

    I was doing a similar experiment using 1.5” long 1/8” 3 degree drafted endmill around the outside of a standing mold core. The cut sounded funny so I walked around the back of the open mill table just as the cutter broke. It flew up several feet and buried itself through my lower lip all the...
  4. G

    Floating balls to prevent coolant evaporation

    We used those floating balls to diminish evaporation on a heated solution of chemicals used to strip nuclear contamination off of inconell before we reprocessed it into new parts. One night the temperature got a little too high and the balls started exploding one after another (security cam...
  5. G

    Speeds and feeds for plutonium

    I toured a radioactive machining facility in the late 90’s. All of the operators were on one side of the glass, all of the machines were on the other side. Everything appeared to be done by robotic grippers. I wish I could have looked closer, but I don’t even think I was supposed to see as...
  6. G

    Instructor approves cutting steel at 2000sfm

    I love breaking shit, especially other peoples shit. One of the first questions I ask when someone calls me in to help with a production program. How hard do you like to push your machine. If they tell me push them as hard as they’ll take, I tell them we are going to break some stuff and then...
  7. G

    Trying to prevent a F$@# up

    This is the reason I use thread mills on slides…. That being said, I’ve busted off taps in much more expensive chunks of metal… a $20k injection mold rings a bell. I’ve had success getting a appropriate sized nut and welding it on to the broken tap. Helical boring usually messes up the...
  8. G

    SwissMak or similar machine?

    This oughta be a ten pager. Sent from my iPhone using Tapatalk
  9. G

    1/8" Roughing End Mill?

    I didn’t make a single mistake or write a single bad program today (I took the day off). The longer I’m in this trade, the more I realize how little I know. Sent from my iPhone using Tapatalk
  10. G

    Haas Chatter

    Except for one problem… you can see the same “chatter” on the edge break as well. This is certainly a kinematics issue. Run the same part on two machines with the same code. Don’t let the tech leave until the DM or DT finish looks as good as the Minimill or VF. Sent from my iPhone using...
  11. G

    Haas Chatter

    That is exactly the “chatter” we have seen. It can be improved, but not eliminated by tuning the servos and friction settings. This is by no means the worst I’ve seen. Sent from my iPhone using Tapatalk
  12. G

    Haas Chatter

    It don’t really understand the physics of it, but speed doesn’t seem to be the issue. It is more friction (sticktion) in the ball screw. In other words the assembly is stopping and popping rather than moving smoothly. If I had to guess, the chatter you are seeing is visible and tactile...
  13. G

    Haas Chatter

    How much mass weight do you have on the table, and how centered is the weight? This can have a huge impact. With the TRT160, we had to tune one down to VF speeds and absolutely center the trunnion on the table. Sent from my iPhone using Tapatalk
  14. G

    Haas Chatter

    The problem you are having is probably related to how much weight you have on the table vs how much weight the machine was “tuned” for. The DM/DT series has a low table weight rating. They are very temperamental for servo acc/dec and friction settings. It will take a very good technician a...
  15. G

    Kalamazoo belt sander

    About 20 years ago I copied a Kalamazoo and built it in an afternoon. I used scrap material from around the shop and an 8” bench grinder (on the other side I mounted a 3M deburring wheel). Only thing I had to buy were bearings for the top idler wheel. My boss swore it was never going to hold...
  16. G

    Metal "shavings"

    I hate lathe work so much, it pisses me off when the recyclers call my aluminum chips from my mills “turnings”…. It’s like they’re cheapening them. Sent from my iPhone using Tapatalk
  17. G

    Thread depth using 60 degree

    The other thing is, we always (???) check our cut threads and sneak up on them. In other words, if I’m cutting external threads like you are, I’ll determine the thread depth by looking up the major and minor diameters in my Machinist Handbook (or Google). Then I’ll run my program and check my...
  18. G

    Thread depth using 60 degree

    The longer I’m in this industry (~25 years) the more I realize how little I know :) Self -acknowledged gaps: -a true understanding of threads and thread specs. -heat treating -cutter geometry -women Sent from my iPhone using Tapatalk
  19. G

    .040 slitting saw cut need input please

    I just use plain old HSS jewelers saws for that type of slot. I’d probably start at 2500 RPM and 10 inches a minute. You’ll be able to hear how it sounds. If you turn them too fast they melt the aluminum and things go bad fast. I use a fairly coarse pitch blade. Sent from my iPhone using...
  20. G

    Thread depth using 60 degree

    Okay, I’ll use an example…. I frequently program threads either with a thread mill on the mill or single point on the lathe. One of my cam systems uses the minor diameter for external threads and the major diameter for internal threads. The other system requests a thread depth. It doesn’t...

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