# Some Hand-me-down Drill Bits



## maker of things (Dec 6, 2015)

My FIL gave me some MT4 shank drill bits: 1 5/32, 1 15/32, 1 17/32,  1 21/32 and 1 29/32".  After using a couple to open up some holes prior to boring I added 5/8, 3/4 and 1" to the collection


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## brino (Dec 6, 2015)

Those are some serious drill bits.
What are you turning them with? You must have good low-speed control to make the best use of them.

-brino


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## extropic (Dec 6, 2015)

The heck with the twist drills. I'm more impressed by that very nice custom storage tray.   

OK, the twist dills are useful too.


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## Uglydog (Dec 6, 2015)

Great storage box!!

Caution: these things tend to breed. You'll open the box in a few weeks and there will be more. Soon they will be all over the shop. Remember Tribbles? http://www.mojvideo.com/video-star-...th-tribbles-20-15-apr-24/8410599766d89eba8f1d

Gonna have to add on to the shop. Warn your wife, mention the curse of the MT4 that you FIL passed on to you.
This is a great way to add a small extension on to the shop. Start small, maybe 20x30.
Knowing that all this happened on account of your FIL will make your wife fully supportive.

Daryl
MN


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## maker of things (Dec 7, 2015)

My PM 1440 has mt4 taper in the tailstock.  I only tried them on aluminum so far, but boy what a timesaver when boring is on the menu!


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## kd4gij (Dec 7, 2015)

^ yep. I used a 2 1/2" one today. Just remember, when drilling soft metals don't step drill.


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## maker of things (Dec 8, 2015)

kd4gij said:


> ^ yep. I used a 2 1/2" one today. Just remember, when drilling soft metals don't step drill.


This like many things is new to me.  Could you explain it to me with some more detail and/or better yet pics?
The scenario is to bore this 6065 to 1.5", after center drilling, I should have just gone straight to the 1 15/32"?  Then do you peck a lot to break chips or how do you deal with that massive curly chip?


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## 4GSR (Dec 8, 2015)

What I generally do when I have to drill a large hole on the lathe or even on the mill, I'll drill a small hole, say 3/16" first to the depth needed or as deep as there is flutes.  Then drill with the larger diameter bit next.  Very seldom step drill other than this.  Step drill only if HP is an issue, like on my 9" SBL, then I'll step drill.


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## Uglydog (Dec 8, 2015)

What 4gsr wrote.
Also, the initial hole should be large enough to clear the webbing of your larger drill.

Daryl
MN


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## maker of things (Dec 8, 2015)

Pardon my ignorance, but why not intermediate steps, just a waste of time, or is there a negative effect on the part?


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## kd4gij (Dec 8, 2015)

If you try to step drill in softer metals especially brass or bronze ,aluminum , or plastic. The larger drills will tend to grab and pull out of the tail stock.


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## change gear (Dec 8, 2015)

Step drilling can be hard on the bit itself, Sometimes chipping the cutting edge.


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## maker of things (Dec 9, 2015)

So if I understand, by taking one big cut, the cutting load is distributed across the whole edge which in turn will maintain "rearward" force.


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