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1000 pieces, whats the best way to tackle this?

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  • 1000 pieces, whats the best way to tackle this?

    I've picked up a machining job to modify 1000 pieces of fibreglass pole locking mechanisms, drilling a 1/8" hole through the aluminum core (3" total) and reducing the large black section's outer diameter by roughly 60 thou, to get a tight fit in the pole segment. The turning is easy but drilling this hole is proving harder.

    The aluminum core is a gummy grade and the drill likes to wander, its pretty easy for it to come right out the side of the part. Drilling from both ends is acceptable as a 22ga wire has to fit through the centre and it fits well even if the holes are out by half the diameter where they meet.

    I'm trying to find a way that I can do this operation in a few minutes per part otherwise I'm not making any money. I don't have a fast moving tailstock to clear material so I'm thinking of clamping a lathe chuck flat on the mill bed and using the quill to drill halfway, flip the part and drill the rest of the way. That should give repeatability once the chuck is set up.

    Is there anything I can do to optimize chip clearing, maximize speed? Lubricate with WD40 and wash the parts afterwards? Any specialized drill bits or bit coatings that would be ideal for the gummy aluminum?

    How can I minimize the wandering drill? Starter with a center drill to give the bit something good to start running in? Adds time but if it helps drill faster by preventing rubbing then it might be a net gain.

    Picture shows the part before and after drilling. There isn't a ton of room for a wandering bit before its out the side of the part.

    I'd love some experienced fellows' advice.

    Sent from my SM-G930W8 using Tapatalk

  • #2
    Have you considered locking the tailstock to the carriage, leaving the tailstock clamp 'loose' and using the carriage wheel to do the moving? You could probably use something as simple as a hefty zip-tie to lock them together, or loop some plumber's tape around the two, etc. I think you definitely need to start the hole with a spotter or center drill, then if you turn it fast enough, use conservative feed and clear chips often I think you can pretty well stay centered.

    How accurately centered and concentric are the plastic parts? (or are they cast metal?)
    Last edited by chipmaker4130; 12-11-2017, 10:30 PM.

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    • #3
      I would use a parabolic flute drill and Tap Magic for Aluminum. The Tap Magic is miles ahead of WD40, especially on soft, gummy material. The parabolic flute drill needs a spot or center drill to get started right. You could do the spot drill in the lathe when you are turning the diameters and the drilling in the mill as described, half from each end. Both ends would need spot drilled too.

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      • #4
        Have you considered drilling in the lathe using the carriage? You don't even need to lock the tailstock to the carriage. I use a quick change toolpost and a boring holder with an inexpensive straight shank ER collet in the boring holder.

        This would allow you to quickly peck drill.
        www.thecogwheel.net

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        • #5
          Originally posted by enginuity View Post
          Have you considered drilling in the lathe using the carriage? You don't even need to lock the tailstock to the carriage. I use a quick change toolpost and a boring holder with an inexpensive straight shank ER collet in the boring holder.

          This would allow you to quickly peck drill.
          Add a second boring tool holder with a spotting drill, then you can turn, spot, drill, all with the carriage. Like a turret lathe, which was designed for this kind of job.

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          • #6
            Make sure you find drills that will drill 12 xD..
            Excellent job for turret lathe or turret drill..

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            • #7
              How are you going to hold them for drilling? The parts appear to be around 3" x 1" diameter or so. the wall thickness of the center after drilling looks to be maybe 1/8", if the hole is 1/8".

              One end looks chuckable, but the other looks nasty. And with an as-cast finish, they will not run true in a steady.

              It looks as if fixturing is your friend. You may need to rig up a carrier to hold the parts by the two flange portions so you can drill from each end. If you center each end, you can then do the turning, which I assume is of the "spigot" that the parts are sitting on in the picture.

              Does the hole HAVE TO BE 1/8" all the way through? I'd look at a larger size at the end, with the idea of shortening the drilled length that is critical.

              If you CAN drill a hole enough bigger at the end, you may be able to then have the part run in the steady on a bushing that you put in that hole. The bushing would have a hole in it to center up the small drill at the end right where it starts drilling. Hole needs to be larger after that, to allow chips to clear out the end. There is an issue of retaining the bushing, which I have not thought out yet. Possibly a flange on he bushing that will ride "behind" the steady jaws.

              if you can do a larger hole, and especially a bushing, you might be able to drill the small hole in one shot, and not have to drill from both ends.

              You do not show the spigot end, but I assume there is room for the drill to wander a bit once it gets into that area.
              Last edited by J Tiers; 12-12-2017, 01:21 AM.
              1601

              Keep eye on ball.
              Hashim Khan

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              • #8
                I'm trying to find a way that I can do this operation in a few minutes per part otherwise I'm not making any money.
                I would try a jig in the milling machine to center the part and hold it vertical. Looking at the part, a jig would be a block with a close fitting hole in it
                clamped in the vise. Then, a short 1/8" endmill should allow you to drill a 1" deep starter hole nice and straight in all the pieces. Then run the parts
                through a second time with a longer drill bit. I think that will be faster than doing it on the lathe.

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                • #9
                  What about melting it all back down and pouring into new casts?

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                  • #10
                    @J Tiers

                    The aluminum is only 1/4" thick, I think it would be hard to drill much larger than 1/8" diameter for very deep without it wandering out the side of the part.

                    The part can be held pretty well using a piece of the larger fibreglass tubing that the entire part goes into, with a slit so it can be compressed. This sleeve holds around the two largest diameters, which are concentric and accurate enough. Grabbing it like that in the lathe and mill seems to work fine.

                    I'm going to try drilling in the mill and see if it works better. I've also got a 5/8" straight shank JT3 arbor on the way to put a chuck on my QCTP so I can try toolpost drilling.

                    I'll also try with a centre drill to try getting the start of the hole as straight as possible.

                    I'll post how it goes later today. Thanks for the tips, guys.

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                    • #11
                      That looks like a pita x1000

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                      • #12
                        In the mill, use a 1/8" collet to hold the drill bit, not a chuck.

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                        • #13
                          1000 pcs 1/8" dia 3" long holes to soft gummy aluminium and no flood coolant either on lathe nor mill.
                          Call me pessimist but that is going to suck big time. Hopefully you quoted enough high price.

                          Normal process would be drilling to maybe 1/2" depth with stub drill and after that pecking aka pulling out the drill out of the hole every 1x drill diameter. Drill 1/8" deeper and pull out to clear chips...Man that is 20 pecking cycles per part and 20 000 times for the whole batch!
                          I get repertitititititititive strain injury just from thinking about it on manual machine.


                          If I was forced to do something like this I'd consider jury-rigged high pressure coolant system to lathe toolpost and HSS drill with trough coolant holes.
                          Won't be cheap and not sure if you can find one in as small as 1/8"
                          Last edited by MattiJ; 12-12-2017, 11:36 AM.

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                          • #14
                            I've got a nice 1/8" coolant through Nachi drill that I would use for that. Still gonna suck though....

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                            • #15
                              Originally posted by MattiJ View Post
                              1000 pcs 1/8" dia 3" long holes to soft gummy aluminium and no flood coolant either on lathe nor mill.
                              Call me pessimist but that is going to suck big time. Hopefully you quoted enough high price.

                              Normal process would be drilling to maybe 1/2" depth with stub drill and after that pecking aka pulling out the drill out of the hole every 1x drill diameter. Drill 1/8" deeper and pull out to clear chips...Man that is 20 pecking cycles per part and 20 000 times for the whole batch!
                              I get repertitititititititive strain injury just from thinking about it on manual machine.


                              If I was forced to do something like this I'd consider jury-rigged high pressure coolant system to lathe toolpost and HSS drill with trough coolant holes.
                              Won't be cheap and not sure if you can find one in as small as 1/8"
                              You are using the wrong drills , with better drills you don't have to pull out as often. But he should use coolant.
                              In my turret lathe I was driiling thru 10 inch long 1 5 inch plastic round bar. It went well, 5 inches deep per side or more, didn't have to turn machine off to do the whole operation

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