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Recent content by Finegrain

  1. Finegrain

    Thin AL Plate Machining required USA Based Companies ONLY

    Put fillets on the inside vertical corners. Sharp inside corners are a PITA. Also, yes, drilling the holes in the interior ribs is going to be quite the trick. I don't know of any angle-head attachment that is thin enough to fit down in the pockets. Regards. Mike
  2. Finegrain

    Xometry???

    There are probably 20 guys who had a bad experience for every 1 that has/had a good experience. A friend of mine, local shop ~10x the size of mine, one of the smartest guys I know, tried it and quickly concluded it was a waste of time. I use Xometry (since 01/2020) when I have nothing in my...
  3. Finegrain

    NPT Pipe Tap Feeds and Speeds

    Assuming mill, not lathe ... Ugh, ditch the NPT tap and threadmill!! You have a CNC mill after all. Threadmill gives you fine control over thread size, and no termination ridge that you get with an NPT tap. Regards. Mike
  4. Finegrain

    Current AL 6061 price

    Just was quoted $3.85/# for a couple hundred #'s of 5/16" x 2" 6061 Regards. Mike
  5. Finegrain

    Who Makes the Absolute Best Roughing Endmill for Aluminum?

    I really like Maritool segmented/corncob roughers. They are more free cutting than Diamondbacks IME. They last a freaky-long time. Regards. Mike
  6. Finegrain

    How fast (SFM) can you run HSS in 6061?

    Thanks Grant, it's been a rough few months :o
  7. Finegrain

    How fast (SFM) can you run HSS in 6061?

    65 parts in and so far the surface looks fine. Overall cycle time for the part is 9 minutes so it might be a few days before I know how far it got. Regards. Mike
  8. Finegrain

    How fast (SFM) can you run HSS in 6061?

    .0025". More than that and the scallops get a bit more visible than I'd like. Regards. Mike
  9. Finegrain

    How fast (SFM) can you run HSS in 6061?

    The previous operations leave a 6mm thick square edge with .01" extra, so yes, the bullnose isn't removing a lot of metal. Regards. Mike
  10. Finegrain

    How fast (SFM) can you run HSS in 6061?

    Thanks guys! Since I already have the Whitney HSS tool from making the prototypes, I will let it fly and see how long it lasts. Regards. Mike
  11. Finegrain

    How fast (SFM) can you run HSS in 6061?

    The only carbide equivalent I know of is Harvey 32810, but it is only 3/4" diameter and 4 flutes, while the Whitney tool is 1-5/16" diameter and 8 flutes. With scallop height considerations, I probably would have to run the Harvey tool faster than my 16k RPM max to get the same finish as I'm...
  12. Finegrain

    How fast (SFM) can you run HSS in 6061?

    I'm running a Whitney 5/32" bullnose cutter in 6061 to put a bullnose all the way around a ~5" x 20" part. I actually don't know what the practical limits are for HSS cutting 6061. I'm running 1,300 SFM right now, and all seems well. I'd like to go faster, of course, but I don't want to...
  13. Finegrain

    Xometry???

    No, Xometry is not going anywhere anytime soon. They have recruited a lot of shops, enough that they can always find a shop willing to take low-paying jobs. Regards. Mike
  14. Finegrain

    Xometry???

    Xometry is fine IF you have a shortfall in regular work and need some filler to make your monthly/quarterly goals, or just want something to fiddle with while you wait for regular work to pick up. It's VERY difficult to make a living wage on Xometry work. There are some jobs that I've done that...
  15. Finegrain

    Need source for "better" 3/16" 6061 plate

    Hello, I make a family of parts from 3/16" 6061 plate. Parts finish to nominal thickness, ~8" wide, between 14 and 20" long. They get a bunch of pockets and holes put in. Flatness +/-.01", thickness +/-.005". I've been trying to use commodity 3/16" 6061 plate, but much of the time, what I get...
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