Shop Doc Forum » General Questions

1. Anonymous
   Unregistered

   Would like to use an insert drill and blast through holes like they do in the cool videos, but...
   My VMC does not have a thru-coolant setup.
   Can I attain the "recommended" speeds/feeds without thru coolant? Any way to easily set up thru-coolant?
   Are these indexable drill setups worth the expense?

   Posted 3 years ago #

2. Anonymous
   Unregistered

   To get the feeds and speeds the manufacturers advertise you will need the thru-coolant spindle. You can still get some impressive metal removal rates without it though, if you've got a sturdy machine with a good amount of HP behind the spindle.
   Investing in the hollow drawbar and associated pump and other parts is a question only you can answer. Will you get your money back? Will the added coolant flexibility be advantageous to you in other areas (it just might).
   I use several inserted drills, in lathes and mills, and they still work great. I don't have thru-spindle coolant either.
   M2C,
   John

   Posted 3 years ago #

3. Anonymous
   Unregistered

   John B:
   I have a 15/20 HP machine (8000 rpm spindle). Coolant pressure converts to 24 psi (9 gal/min). I think the machine is sturdy enough, but coolant seems to be the issue.
   Do you have any examples of sustainable speeds/feed that you are using now? Do your hole sizes stay tight (tolerance wise)? Thanks!

   Posted 3 years ago #

4. Anonymous
   Unregistered

   JWRX1,
   My most extreme example is a Iscar DR series 2 insert 1.75" drill cutting 4130 that I run at 1200rpm fed at 8.56 IPM on a machine with the same 15/20 HP as yours. The hole is just over 1" through, and the coolant is flooded by two 1/4" nozzles. The inserts last about 1000 holes per pair of edges - though they could go longer if our machine was still fairly rigid.

   I use a couple of Kennametal drills with the triangle inserts also, but they don't have the same feed capacity because they don't evacuate chips as well. Mostly I use them on the lathes because I can use through coolant, and then I can reach about 350 SFPM and about .008 - .010" per rev feed.

   I don't get real tight tolerances, maybe +/-.005" on the mills but I think it is due to the age of our machines. The lathe holes come out within about +/-.002". All the holes I use inserted drills on require additional milling, reaming, threading, or finish turning though - so I haven't really looked for tight sizing. The finish generally is about 93 Ra to 63 Ra at best though.

   Try to get your preferred tool rep to bring you in a drill for test to see what you can do. They make their money on the inserts anyway, not so much the drill. I've always found them willing to put their money where their mouth is, when speaking of major brands anyway.

   Rgds,
   John

   Posted 3 years ago #

5. Anonymous
   Unregistered

   John:
   That is a lot of good info. I had not even thought about the surface finish - just assumed it would be 32 or better, though that might be due to rigidity you mentioned.
   I will talk to the tool rep and see what he can do for me. Thanks again.
   JWrx

   Posted 3 years ago #

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