# Is There A Good Way To Make Oversized/taprered Drill Bits Common Jacobs Chuck?



## jere m (Aug 31, 2015)

Maybe this is a foolhardy or hopeless
	

		
			
		

		
	




	

		
			
		

		
	
 question but I am looking for the best solution I can find. 

I bought a bag of used assorted  drill bits for $20 from Craigslist. I have a very limited income so I was happy to get them. the problem I am running into is many of the bits don't fit my 1/2 inch jacobs chucks. some of the bits were turned or  ground down with a rough finish to fit by a previous owner. I have a small 8x12 hft lathe but I don't dare put the twist end of the drill bit in the 3 jaw lathe Chuck.
I know there are larger jacobs chucks and fittings for tapered drill bits but they are as good as unobtainable for the time being.

so my question is how does one go about turning down the shank of a drill bit or making an adaptor?


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## Round in circles (Aug 31, 2015)

Jere,
How big is you lathe chuck and does it have a hollow cross shaft ,  in other words will the drills actually fit in your lathe?

Here are  one or two way's of skinning your cat that I have used :-
Most drill shanks are fantastic material for turning in the lathe you can get a real good finish using tungsten tipped tooling .

If you have say a 1/4 " end that has been turned down on a bigger drill & you want to remove it  grind it off keeping the tang quenched so it does not harden,  then face it off square in the chuck & put a tiny rounded edge on the faced off end to stop you cutting your fingers as they can be very very sharp.  .

Slit some copper water pipe along its length use it to  wrap around the drills where they will fit in the chuck jaws save for the bit you're wanting to remove.  Cutting the strip to ensure it is circular all round the drill ( no gaps or over wraps )
Centralize the work in the chuck with a DTI if you have one or with the back end of a rounded cutting  tool in the tool post ( you grind it if you have a grinding stone )

Another way if you don't have a grinder or DTI is for you to thread & counter bore a round bar  so that it can hold a 1/4 " diameter steel ball bearing ( cutting the head off big bolts can be useful here ) Then make a coned cap to hold it in place  either by threading the cone or using some epoxy resin to hold the ball in the counter bored hole ensuring that some of the ball bearing is poking out the coned cap to be able to touch the work piece.

I dare say the  simply counter boring the end of a square or round bar and using super glue or epoxy will be OK to make the  indicator tool.
To use the tool you use your eye  to see the distance gap and adjust accordingly
another way is to use feeler blades to measure the run out and again adjust things till it minimized , checking several times that is is true all the way round . .


If you can hold some of the shank wrapped in copper in the chuck so much the better .
I've turned down all manner of drills over 1/2 " like that as well as taper drills .


Here in Great Britain  drills with the shank of a smaller diameter than the body are called Blacksmith Drills..
Using that term you might find a You Tube clip showing you how others do it .
One some of the morse tapers drills I've  managed to turn the half inch shank and still had a workable morse taper to play with.
On one or two of the longer bigger morse taper drills I had to grind off an inch or more with the angle grinder  then resharpen the drill  so that they would fit in my little drill press.

For one 8 mm morse taper drill that I wanted to keep as a morse I turned down a # 2 morse adapter sleeve to a 1/2 " at the tang end ....  there was just enough metal to do it without wrecking things.  It enabled me to do the job .
Morse tapers are very cheap on eBay to buy so I've gone & purchased another two .


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## jere m (Aug 31, 2015)

Round in circles said:


> Jere,
> Slit some copper water pipe along its length use it to  wrap around the drills save for the bit you're wanting to remove.
> 
> If you can hold some of the shank wrapped in copper in the chuck so much the better .
> ...



Thanks  the copper tube should do the trick for most of the bits!

there are a few approaching 29mm I might just have to give up on those. I don't think I can fit enough length in the lathes chuck


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## Wreck™Wreck (Aug 31, 2015)

Put them in the chuck and turn the shanks, most twist drills have soft shanks that turn easily, a full hard drill is difficult to hold in a drill chuck. Don't worry about holding them in a 3Jaw chuck it will not hurt them.
Twist drills have back taper by design, the pointy end of a new drill is close to nominal diameter, the diameter gets smaller as it approaches the shank by a few .001's.

In the USA reduced shank drills are known as "reduced shank drills", also Silver and Demming drills.


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## T Bredehoft (Aug 31, 2015)

Put the twist end in the chuck far enough into the chuck that you clamp on the round part, just below the flutes.  Turn them down to 1/2, or anything smaller than 1/2, but be sure you then tighten the tailstock chuck very tightly when using them to drill, you will have removed the hard skin on the drill and it won't be as easy to hold, will want to spin.


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## Round in circles (Aug 31, 2015)

jere m said:


> Thanks  the copper tube should do the trick for most of the bits!
> 
> there are a few approaching 29mm I might just have to give up on those. I don't think I can fit enough length in the lathes chuck



Ever thought of turning those biggies between the chuck ( again  with a copper wrap  ) and have the tang end in a live centre at the tail stock then turn them down at the tail stock end ( most of the big morse tapers should have an accurate counter sunk center in the end of the tangs ) .


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## bill stupak (Aug 31, 2015)

How about milling hex flats on them? That would reduce the size and make them twist resistant in the drill chuck.

Bill


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## Wreck™Wreck (Aug 31, 2015)

T Bredehoft said:


> Put the twist end in the chuck far enough into the chuck that you clamp on the round part, just below the flutes.  Turn them down to 1/2, or anything smaller than 1/2, but be sure you then tighten the tailstock chuck very tightly when using them to drill, you will have removed the hard skin on the drill and it won't be as easy to hold, will want to spin.


Actually twist drills are hard all the way through and not cased hence they may be sharpened, the shanks are not hard so that they may be more easily held in a drill chuck, the harder the shank is the harder it will be to hold in a drill chuck. I am sure that you have noticed that twist drills that have been spun in a chuck often have deep grooves and ridges from the chuck jaws, center drills and taps have full hard bodies and shanks respectively which makes them difficult to hold securely in a typical drill chuck and are not grooved when spun. The soft twist drill shank is actually slightly deformed by the jaws allowing them to be held more securely.

Do this test, use a file and run the sharp corner over the shank of a quality twist drill, PTD, Chicago Latrobe or Guhring say, then over the cutting part of the drill and let us know the results, then try it on the shank of an endmill or the body of a center drill. Chucking reamers also have soft shanks suitable for easy turning.

It may seem counterintuitive but the harder the shank the more difficult the tool is to hold in a chuck.


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## jpfabricator (Aug 31, 2015)

What is the taper of your drill press quill? You may be better off finding some morse taper collets that match your quill taper 

Sent from somewhere in east Texas!


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## brino (Aug 31, 2015)

Jere,

A silly question.......but are you certain that your drill press does not use a Morse taper to hold the stub that the drill chuck is on?

I was offered a bunch of taper shank bits because the owner jokingly said that "my chuck won't hold them!".
What he missed was that his drill press did use a Morse taper, like the middle row in this picture (from wikipedia):
https://en.wikipedia.org/wiki/Machine_taper#Morse




It is driven out using tapered wedge thru a slot in the spindle.
Here's a good reference.
http://www.ereplacementparts.com/article/3425/How_to_Remove_and_Reinstall_a_Drill_Press_Chuck.html

Have a look, this may save some effort.

-brino

EDIT: The above was written because I saw a morse taper bit above.  Perhaps I mis-understood and you are asking about holding cylindrical shank drill bits.


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## jere m (Aug 31, 2015)

Lots of great responses guys big thanks! I should have mentioned I am just a hobbist starting out (if that wasn't already apparent). The metal lathe has a Morse taper 2 tailstock and 3 jaw side, I think my Frankenstein press has a mt2 but I haven't pulled the Jacobs Chuck out to verify this. (Thanks brino for that how to link!). I like the idea of using collets and the tapered shaft and realise there is more mechanical grip that way. With some of the bits being tapered some being ground and some just being 1 inch or so with no taper, I would rather just make them all consistent. They will only be used every now and then so I will just turn the bits down and really tighten up the Jacobs.

Thanks to you guys for covering the fact that the bits shanks are not hardened, that's news to me but it makes good sense. The shanks of the bits look ground with a grinder so I assumed they were hardened.


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## brino (Aug 31, 2015)

jere m said:


> I think my Frankenstein press has a mt2 but I haven't pulled the Jacobs Chuck out to verify this.



So then you can keep the MT-2 taper shank bits and use them directly in the spindle.
The other may still need to be modified.

One problem with the collet suggestion is that something needs to push or pull the collets in. Typically, it's either:
1) a draw bar, but you need a hollow spindle (which I've never seen on a drill press due to the splined drive shaft), or
2) you need a threaded nose around your MT2 spindle for a collet nut; I have seen a few drill presses with that, but it's not common.

I have seen a male MT2 to female MT3 socket adapters like this:
http://www.amazon.com/Morse-Taper-A...qid=1441074771&sr=8-63&keywords=morse+adapter
These can add a lot of length to the entire arrangement.

-brino


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## jere m (Sep 1, 2015)

I have yet to attempt to take the quill assembly apart but there is a larger nut above the Jacobs Chuck (I need to find a larger wrench). just out of curiosty might that be the threaded nose you mentioned? or does it have another fuction perhaps?


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## brino (Sep 1, 2015)

Jere,

It is difficult to tell from your photos exactly what kind of spindle that is.
If you crank the spindle down, does it have the "window" for driving a wedge in like the other link I posted above?

I know you said it's a "Frankenstein" drill press, but look for any indication of manufacturer. Pictures may also help someone here identify it.

After my last post I also realized you could go with a collet chuck like these:
http://www.amazon.com/HHIP-3900-0502-Spring-Collet-12-piece/dp/B00R138SNK
http://www.ebay.com/itm/New-ER32-MT...ER32-collet-/160632780638?hash=item256675b75e
One issue though is that they are designed for a draw-bar to pull the tapers together.

Of course the big drill bits do NOT require a draw-bar, so you may not for drilling. Just beware that with say an MT-2 drill bit it has that flat tang on the back end and that's what the wedge hits to push it out of the spindle. The collet holders above do NOT have a flat tang! However, you could add a properly sized bolt or socket-head cap screw (perhaps with lock-tite on the threads) to provide the same function. I use that idea in my lathe tail stock with my 3-jaw chuck. Without some means of ejection one could get stuck in your drill-press spindle!

However, do not use the collets for milling without a draw-bar or collet nut holding the tapers together. The side forces and interrupted cuts during milling can lead to the tapers coming apart.

If you go with collets, make sure you get a collet system that allows the large sizes you need.
I know my ER-32 system only goes up to 3/4", that may not be big enough for you.

This link shows some size ranges for various collet systems(though I do NOT know if it is perfect or complete):
http://www.techniksusa.com/metal/cnaerpci.htm

Let us know which direction you go.
Good Luck!
-brino


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## brino (Sep 1, 2015)

Jere,

One more thought about that hex section above the drill chuck.
It may be that the chuck is threaded onto the arbour, the hex could then be used when tightening/loosening the drill chuck onto the arbour.

Like these:
http://www.amazon.com/Jacobs-Chuck-...1441112201&sr=1-13&keywords=drill+chuck+arbor
http://www.ebay.com/itm/2MT-SHANK-T...MT2-ADAPTER-/111590830237?hash=item19fb54f09d

but with a hex cut on the shoulder.

-brino


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## Bill C. (Sep 1, 2015)

When I was working at GE, my Dad or one of his buddies would ask our foreman if we would turn down a drill shaft so it would fit a 3/8" or 1/2" drill motor.  Use a carbide lathe bit, most of the shafts are soft compared to the cutting end.

Nice assortment of drills for $20.


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## jere m (Sep 1, 2015)

brino said:


> Jere,
> 
> It is difficult to tell from your photos exactly what kind of spindle that is.
> If you crank the spindle down, does it have the "window" for driving a wedge in like the other link I posted above?
> ...


thanks for the crash course in collets and adaptors brino! the drill press is unmarked manufacturing plates have all been removed. I have been told that I have a head from a chas g Allen ("sensitive drill)" was the model possibly gang drill. I have contacted the company ( family members still own it and sell parts) and was told hardly anything I have was original.  the castings for the head were made for 30 years if I remember correctly starting around 1910 or so.  mine has some bearing that are patented in 1904 so that's all I know for certain. some where along the line the one I have was changed from line drive to a small split phase motor with v belts.

there isn't a window on the quill it seems and looking at photos of other Allen presses there isn't an exposed threaded section. it must be for the Chuck like you thought. the Chuck isn't original to the machine but it is pretty old.


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## jere m (Sep 1, 2015)

Bill C. said:


> When I was working at GE, my Dad or one of his buddies would ask our foreman if we would turn down a drill shaft so it would fit a 3/8" or 1/2" drill motor.  Use a carbide lathe bit, most of the shafts are soft compared to the cutting end.
> 
> Nice assortment of drills for $20.


 
thanks for the tip bill, the bits that I can use have really come in handy lately. I don't think I have even seen larger sizes at the local big box stores. so I got lucky coming across the bits. they are all USA made from different companies and all  pretty sharp.


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## 4GSR (Sep 3, 2015)

jere m said:


> View attachment 109724
> 
> 
> I have yet to attempt to take the quill assembly apart but there is a larger nut above the Jacobs Chuck (I need to find a larger wrench). just out of curiosty might that be the threaded nose you mentioned? or does it have another fuction perhaps?



That's a Model 6A drill chuck in the picture.  That has a Jacobs taper mount in the back of it.  If it was threaded, it would be a Model 6B chuck.
The nut is more than likely used to extract the chuck from the spindle.  Get you a open end wrench on that nut and hold backup somehow, twist on it and see what happens.  I sure the nut is right handed.

Ken


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## jere m (Sep 3, 2015)

4gsr said:


> That's a Model 6A drill chuck in the picture.  That has a Jacobs taper mount in the back of it.  If it was threaded, it would be a Model 6B chuck.
> The nut is more than likely used to extract the chuck from the spindle.  Get you a open end wrench on that nut and hold backup somehow, twist on it and see what happens.  I sure the nut is right handed.
> 
> Ken



Very  good, thanks for chiming in in ken and good eye!


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