Roughing out a Bore with a Drill
#1
That's right...... 1.00" drill to depth, and rough to 3.345" dia. with the same tool. 

Sounds impossible, but not with the right tooling............

Here's my Haas ST20 all loaded up to make some aluminum sleeves. 

Material size = 3.750" Dia. cut 2.00" lg.


[Image: 20141114_111720_zpsn9kzvir1.jpg]



[Image: 20141114_111713_zps0c3qmxji.jpg]



Here's the tool. 1.00" Center-Dex Inserted Drill.


[Image: 20141114_111638_zpsgnutza6n.jpg]


The drill drills to depth, or in this case (due to total depth being longer than flute length) drills .500" deep then roughs dia to 3.345".

After drilling .500" deep drill moves over in the "X" axis .250" to open the bore .500" in steps until 3.345" Dia. This repeats in .500" deep increments until final depth of 1.500".

Here you can see the piece has been completely roughed out and is ready to be finished bored to 3.375" +.0015"/-.0000".


We also rough turn the OD before finishing the ID.

[Image: 20141114_111601_zpscbwlmj9c.jpg]


Here we are all finish bored and OD finish turned to 3.625" dia. I use a .500" dia. solid carbide boring bar with aluminum specific inserts on the ID and OD to achieve the finish and hold size without issue, always using Walter inserts of course.

Now to part off 1.500" lg.


[Image: 20141115_085414_zpscl423siy.jpg]


Before and after.

[Image: 20141115_093901_zpsjmxvrst2.jpg]

[Image: 20141115_093924_zps0dc0eyot.jpg]


[Image: 20141115_102646_zpszkrg3vlm.jpg]


And that my friends is how you drill and bore with one tool.

Later,
Russ
Reply
Thanks given by:
#2
Now that is good Thumbsup 
Smiley-eatdrink004 
DaveH
Reply
Thanks given by:
#3
Disgustingly good!
thanks russ! Thumbsup

Smiley-eatdrink004
Busy Bee 12-36 lathe, Busy Bee Mill drill, Busy Bee 4x6 bandsaw, Homemade 9x17 bandsaw, Ad infinitum.
Reply
Thanks given by:
#4
Hi Russ - the centre dex drill is static in that carousel isn't it?
Hunting American dentists since 2015.
Reply
Thanks given by:
#5
(11-15-2014, 08:51 PM)Mayhem Wrote: Hi Russ - the centre dex drill is static in that carousel isn't it?

Hi Darren,

If you mean fixed or stationary, then yes.  

Best Regards,
Russ
Reply
Thanks given by:
#6
Hi Russ - yes, that is what I meant. I'm not totally familiar with the world of CNC machining but I know some machines have live tooling.

So in this application, you are using the centre dex drill to plunge the hole and then (effectively) using it as a boring bar. Is that correct? If this is the case then I guess the tool has to be indexed appropriately.

So given the same tool, I could do this on a manual machine. However, I doubt I could do it with a standard drill.
Hunting American dentists since 2015.
Reply
Thanks given by:
#7
You are correct Darren.

Using the CenterDex to drill then bore is just a matter of making the first plunge with the tool "on center", then using the outboard insert (aligned with X travel) to step over.

Because the tool has no side clearance angle (square inserts), it's not good as a finish tool but a fantastic rougher.
Reply
Thanks given by:




Users browsing this thread: 2 Guest(s)