to bore or to drill? - Page 3
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  1. #41
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    Quote Originally Posted by Andy221 View Post
    Nice excuse, and I believe I said 5" not 3. Not that it really matters.

    What's your address?

    Seriously?

    2.5" drill + 6(.4) = 4.9" with .1 for a cleanup pass.
    Last edited by TeachMePlease; 04-21-2015 at 03:50 PM.

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  3. #42
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    Quote Originally Posted by drewboyer View Post
    2.5" spade 3" deep 4 minutes. Then 6 .4 doc passes and 2 finish cuts about 10 or 12 minutes. About 15 minutes total.
    Wouldnt that be faster with a 4.875" drill

  4. #43
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    Quote Originally Posted by Myrmidon View Post
    Wouldnt that be faster with a 4.875" drill
    Fastest with a 5" drill, but the biggest I could drill is 3.5"

  5. #44
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    "If the taper and its socket are clean and free of burrs and scores and you are drilling from the solid there is no need for aids like lathe dogs, set screws etc. If I caught a lathe hand drilling a tailstock quill for setscrews I'd fire him so fast the echo would slap back and break his ankles. I've run lathes 40 years old that still had smooth quill tapers that held drills acceptably. I've also run lathes whose quill tapers had been re-ground a few times. So long as the taper seats properly they will not slip under drilling thrust. "

    Very true, Forrest, but not a reality with the clapped out junk I am forced to use at my day job. Keep in mind, this is the same place that has a Meuser lathe that cuts over 1/8" out on a 14ft part (vase shaped with the middle of the vase out .140) and the boss sees no reason to do anything to it. "Just bump it in and out." You do what you have to do. The spindle taper on the radial drill is so screwed that not only is the tang driving, it has rounded off on the corners and will push the chuck out if it gets unloaded. More reasons why I love working in my own shop.

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  7. #45
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    Quote Originally Posted by Mcgyver View Post
    drilling will always be the fastest way to remove material, but gawd who wants to crank the tailstock quill for days.

    Build a carriage power drilling attachments like this smart folks and Dean Smith and Grace do. Bolts to the carriage dovetail with a stop for centre. It take straight shank MT adapters so you don't have machine the MT and could have it up to 5 or 6 MT if you like. I've big chunk of cast iron waiting to be made into one....#673 on the TDL

    I thought nearly everybody used Aloris tool posts; they have a tool block that carries a morse taper socket, allowing drilling and tapping to be performed with the carriage; this has the added benefit of not messing the tailstock taper when drills slip, few lathes having tang slots to help in driving the drill and keep it from spinning in the taper.

  8. #46
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    Quote Originally Posted by benmychree View Post
    I thought nearly everybody used Aloris tool posts; they have a tool block that carries a morse taper socket, allowing drilling and tapping to be performed with the carriage; this has the added benefit of not messing the tailstock taper when drills slip, few lathes having tang slots to help in driving the drill and keep it from spinning in the taper.
    Pay attention, that boy at the back of the class!

    1. Very few people use toy tool posts on decent sized lathes.
    2. As explained by Forrest a few posts back, the tang is for ejecting the drill not for driving. If the drill has slipped in the taper the tang isn't going to prevent damage to the taper and the drill.



    PS:- I didn't realise that JW had spare accounts for use in an emergency.


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  10. #47
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    When doing a similar operation a few months ago we used a face grooving tool and cut the whole core out. We were a bit short after coming in from both sides so we had to cut out a small section to fit the bar into the part. It went pretty quick and we have used all the drops on other projects.

  11. #48
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    Nobody mentioned using a big old iron mill with feed on the quill (or the knee) to hold a large drill for the initial roughing. Once hole is in, transfer to lathe for boring. Daniel

  12. #49
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    If you have a lot of these to do on a repeat biz cycle...the better way
    is to not scrap all the 5 in dia hole by turning into chips... WASTING $$$
    a better way... Gun DRILLING... or maybe it's trepaning... what happens is
    the cutter/ tool holder looks like a pipe with inserts in it and the inserts
    cut the od and the ID and that creats your required hole, and a SLUG for the core
    Now you need a job to use that core and your material ends up being free...

    IF all that is not feasable, get ya a W&S or like HUMUUNGUS TURRET LATHE...
    a 3A will love those parts.... leave stock for your CNC the 3A will rremove metal
    like you can only imagine... and they do it... and all the while not mistreating the CNC machine
    preservin its accuracy... and life...

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  14. #50
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    You didn't mention the quantity but I have found that buying the stock cut to near net length and core drilled close to the smallest finished diameter is an economical way to go in many cases. Let your metal vendor help you, tell them what you want. If the stock comes into the shop pretty much ready to finish you almost always save money. And you will have the drops as well. Why turn all that perfectly good material in to chips?

  15. #51
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    Quote Originally Posted by benmychree View Post
    I thought nearly everybody used Aloris tool posts; they have a tool block that carries a morse taper socket, allowing drilling and tapping to be performed with the carriage; this has the added benefit of not messing the tailstock taper when drills slip, few lathes having tang slots to help in driving the drill and keep it from spinning in the taper.
    +
    The tang on an MT should never be "driving" anything.

    The taper drives the drill. The tang is for removal.

  16. #52
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    I would drill with a 3/8 to 1/2 pilot and follow up with a 1.5" drill to clear my boring bar and then bore. Your final drill should let you fit your biggest boring bar.


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