# Center drill for lathe



## rgray

Someone on this site (forgive me for not looking up the name) made a very nice center drilling attatchment that went into a large boring tool holder.

That got me started and I built a quick one from a dead cordless drill (seem to have plenty of those).
I cut off the chuck shaft and pressed it into a larger shaft, built bronze bushings, stepped the end to 3/8. Just attatch another drill and it does a nice job of center drilling on the lathe. The picture of it is at the bottom of this post. I couldn't seem to get it where I wanted it.


The drill motor is very small on cordless drills nowdays so I got to thinking about having the tool holder hold the entire power unit. I had a LI drill whose batteries had gone bad so onto another project.
I cut the dovetail on my shaper 
	

		
			
		

		
	

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till it fit my QCTP
	

		
			
		

		
	

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Drilled and bored till the drill motor fit
	

		
			
		

		
	

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And ended up with a powered center drill. It is not compleatly finished. It needs a depth stop and something better done with the wiring and switch. I run it with a motorcycle battery but and 12 volt would work fine.
	

		
			
		

		
	

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This last pic was the first one in my post can't seem to make it go where I wanted it....The drill unit has .002 .TIR
	

		
			
		

		
	

View attachment 44495


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## tkingmo

Looking forward to your pictures.


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## PurpLev

I believe you refer to Pauls (8ntsane) qctp attachment here (post #6):
http://www.hobby-machinist.com/show...op-Made-Tooling!?p=51837&viewfull=1#post51837


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## rgray

the pics are in the text as attatchments but don't open unless clicked on. Is that cause they were to large a file? They show up very large when opened.


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## Old Iron

rgray said:


> the pics are in the text as attatchments but don't open unless clicked on. Is that cause they were to large a file? They show up very large when opened.



When i click on them all i get is Invalid Attachment specified. :nuts:

Paul


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## rgray

Here's those pics that didn't work the first time. (hopefully).
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The initial cut on the dovetail was done with a skill saw. Then the shaper cleans that up and cuts the corners of the dovetail easily.


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## Chucketn

Sorry, I still get "invalid attachment error".

Chuck


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## rgray




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## rgray




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## Chucketn

That one worked! What did you do different?

Chuck


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## rgray




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## rgray




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## rgray




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## rgray

Pics work one at a time. 6 at a time just to much maybe?


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## Chucketn

Nice work. I have a Firestorm waiting for this type of application.

Chuck


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## mech1

rgray said:


> Someone on this site (forgive me for not looking up the name) made a very nice center drilling attatchment that went into a large boring tool holder.
> 
> I run it with a motorcycle battery but and 12 volt would work fine.



Do you know the current the motor draws under load?

Werner


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## rgray

I just tested it and it draws 2.5 amps drilling. If you drill with more force than what would seem normal it draws 3.5 amps. If you hold your hand on the chuck and realy slow it down it draws 10 amps.


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## mech1

rgray said:


> I just tested it and it draws 2.5 amps drilling. If you drill with more force than what would seem normal it draws 3.5 amps. If you hold your hand on the chuck and realy slow it down it draws 10 amps.



you could use the power supply unit from an PC, they usually can deliver this current.


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## rgray

> you could use the power supply unit from an PC, they usually can deliver this current



Wow been over a year...drill is working great. I had a cheapo battery charger that the electronics went bad in so I used it's transformer to power an aditional halogen work light and the drill also.
The bolts coming out of the side of the switch box are the + and - for the drill. Black bolt - silver bolt +.
I did buy a set of screw machine drills. ussful being short in this app.
If I was to build another I would build it with a longer body so the drill chuck was farther back, maybe so the front of the chuck was even with the toolpost.
CIMG2127.JPG
CIMG2128.JPG


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## coolidge

This is brilliant, I have been thinking it would be great to have a live tooling head on my G4003G and now my mind is abuzz with ideas! That these drills have clutches the opportunity for tapping is also in play...(Coolidge wanders off mumbling to himself)


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## rgray

coolidge said:


> This is brilliant, I have been thinking it would be great to have a live tooling head on my G4003G and now my mind is abuzz with ideas! That these drills have clutches the opportunity for tapping is also in play...(Coolidge wanders off mumbling to himself)



That is good thinking on the clutch....Completely missed that myself....the drill head is self locking so I figured tapping was out(not being able to rotate by hand) But I can see where being carefull with the clutch setting it could probably be done.


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## ScrapMetal

Great idea/design but I would have one concern, are those holes on the top of the unit all that the motor has for ventilation?  It might be worth consideration to cut some unobtrusive slots underneath or on the back side to allow for better air circulation/cooling.  Heat build up is the bane of motors.

Just a thought,

-Ron


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## coolidge

That big block of aluminum probably dissipates a lot of heat as a heat sink. Machine some fins in it then it would look even more beastly!

- - - Updated - - -



rgray said:


> That is good thinking on the clutch....Completely missed that myself....the drill head is self locking so I figured tapping was out(not being able to rotate by hand) But I can see where being carefull with the clutch setting it could probably be done.



I just tapped a bunch of holes with my Makita cordless drill installing a DRO on my lathe so I have tapping on the brain. The clutch works great especially for small taps. Speaking of which I brazed together an extended reach hex drive tap holder for that job. It would help if the drill was mounted on a slide that I could unlock so the drill was free to move in/out while tapping with a forward/reverse switch wired up. If I could figure out how to index/lock the spindle I might go more powerful than a drill motor and have some fun with some end mills!


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## rgray

coolidge said:


> If I could figure out how to index/lock the spindle I might go more powerful than a drill motor and have some fun with some end mills!



Now you're talking....I  have the fix for that also. I installed a degree wheel on my spindle to index it for drilling holes at 90 degrees 180 deg etc.
it's on here at: http://www.hobby-machinist.com/show...ree-wheel?highlight=wind+turbine+degree+wheel


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## rgray

ScrapMetal said:


> Great idea/design but I would have one concern, are those holes on the top of the unit all that the motor has for ventilation?  It might be worth consideration to cut some unobtrusive slots underneath or on the back side to allow for better air circulation/cooling.  Heat build up is the bane of motors.
> 
> Just a thought,
> 
> -Ron



Yes....they were supposed to be on the bottom :whistle:. Probably better on the top as heat rises...the fan on the motor is still there to push air....I intended more venting but used it alot before finishing and it never really seems to get hot. So I never added any more. I'm sure it gets hotter than I think it does...as touching the aluminum block to see how hot the motor is.. is probably not a good indicator...The only openings are those three holes and the ones where the wires enter....they are extra large with the idea that they were air intake holes....

Like so many other unfinished things around here...sometimes I feel like the king of unfinished projects.


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## great white

Oh great! yet another project I have to build and I haven't even picked up my lathe yet!

Great idea on re-purposing the cordless drill. 

It seems I always have an extra one lying around too. Not because the drill breaks, but because the batteries get knackered and it's usually just as cheap to buy a new drill. I know at least one is going to get a new life....


:thumbzup:


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## rgray

great white said:


> Oh great! yet another project I have to build and I haven't even picked up my lathe yet!
> 
> Great idea on re-purposing the cordless drill.
> 
> It seems I always have an extra one lying around too. Not because the drill breaks, but because the batteries get knackered and it's usually just as cheap to buy a new drill. I know at least one is going to get a new life....
> 
> 
> :thumbzup:



Yep ...My first li-ion battery fail....Been thinking of building another...maybe on a rod so the assembly slides and lockable so the crossfeed can still be used for the drilling.....It's a bummer when the drill bit is just alittle to long...sometimes zeroing the DRO ....moving over....installing drill bit...then returning to zero works....other times it's not enough....and it could have been done if the cross slide was angled away from the center....then zero does no good... angle the cross slide....reset to square.....and drill....wishing I had the foresight to have angled first.


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## randyc

VERY cool idea !


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