morse taper slip-out???? Please help

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rsulli16

rsulli16

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Jun 9, 2010
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Had a good one this morning. i was drilling a blank on the lathe. i had just reached my depth, slow and easy all the way. i unlocked the tailstock and pulled it away from the blank. the tailstock came, but the jacob's chuck and drill bit stayed in the blank!! of course wobble wobble wobble, i moved fast as i could to turn it off, but too late.

the blank shattered, the drill bit( 3/8") broke and the chuck and half a drill bit was GONE!!! i looked everywhere. apparently it missed me :):):) the garage door was open, i dont recall hearing anything bouncing around the garage so i assume it went out there somewhere, hope my kid doesn't find it with the lawn mower.

its a jet 10-14VS, i have no thru hole on the tailstock for a treaded rod like the headstock side.the chuck was an el cheapo from HF( I hope the answer is that easy)

i have to prevent this from happening again. i was alone at he time, never mind taht i could have bled out on the garage floor, what really concerns me is:
sometimes my wife or kids comes out to talk with me when i am turning, i have to know what happened.

what could have caused this? i'll try anything to fix it.
please everybody pitch in on this one.!!

Thanks in advance
Sulli
 
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Glad to hear the you survived unscathed!

When I drill on the lathe like that... I will put one hand on the Jacob Chuck and the other on the tailstock and back it out together. Holding on to all of it at once.
 
Whenever you remove your tailstock and the drill chuck, hold the chuck with your free hand--pull IT out, not just the tailstock.

Most of the time this is not an issue, but the circumstances you describe are certainly expected, occasionally.
 
Keep a snug grip on the drill chuck going in and coming out -- if the friction on the MT comes loose it will spin in the taper and bad things can happen. If the grip on the chuck feels strong pressure, you need to back off immediatly. Drilling is neither a speed nor power exercise. You get a feel for the drilling pretty fast.
 
Crashmph said:
When I drill on the lathe like that... I will put one hand on the Jacob Chuck and the other on the tailstock and back it out together. Holding on to all of it at once.
Click to expand...

+1 on this. I have had the jacobs chuck come loose, but luckily nothing as serious as yours. I now hang on to it until well clear of the blank.

Chris
 
Been there, done that almost. Learned real quick to hold on to the Jacobs chuck when retracting the bit from the hole. I usually hold the chuck and retract it with the tail stock feed then just slowly slide the tail stock back to release the bit from the hole. These tools, even the most benign, can and will bite you. They have no conscience. Glad to hear you are OK.
Charles
 
I have a nice scuff from a Jacobs chuck coming out of the tail stock on my face shield. Thankful that I did have it on, the chuck would have nailed me under my left eye, perhaps even breaking my cheek bone even eye socket.
From then I always have a hand on the chuck going in or coming out of what ever blank. and my Faces shield.
 
I did the same thing about 2 weeks ago with a 10mm bit. Shattered, broke the blank/bit and threw the jacobs chuck over my head. Gets you heart pumping don't it.
 
Clean and accurate matching tapers are essential for them to work correctly , small nicks and marks on either can change the gripping power of a morse taper as its essentilly a "friction wedge" as the main load is applied the pressure on the tapers will keep it in place ,at worst it will spin while drilling in its sleeve on the tailstock, its not uncommon for this same thing to occur in a drill press as well ,with bad results as the chuck is spinning as it drops out. any dirt or grease or other contaminants in the sockets will prevent a good surface connection ,not obvious till it comes apart :( . In a lathe with drilling as advised hold the chuck when removing from the drilled hole . There is a plastic taper cleaner that is useful for cleaning out the female tapers, and a fine wet and dry sandpaper to ensure the male taper is clean smooth and will grip correctly , remembering that as in all engineering there are variations in tolerances and even "new" parts can have variations in matchups of parts, doesn't need to be much to have a failure . On another note ,I have seen that chucks for woodlathes tend to have shorter tapers than the more standard drill chucks and lathe chucks with the extended "tang" for removal ,so even more important to match the tapers as best as possible for a good contact. Cheers ~ John
 
my first thought when I read this was "wow .. sounds like that blank
got seriously overheated!"
May or may not be the case, but if you don't clear often and allow the
bit to cool, it will overheat the bit.. the blank can swell from the heat,
and turn it into a vise, clamping your drill bit tight in the wood. Now you
have an overheated bit being held in place, and a 1/2 or 1hp motor trying
to turn it. That kind of torque.. something has to give.
Or maybe it was nothing like that.
 
I also hold the chuck when I drill on the lathe. Also, if you have drilled to depth already, then I would turn off the lathe first, then retract the bit.
 
Only took having that happen once for me to start holding the chuck...

I was drilling brass when it happened. The brass survived, and surprisingly so did the chuck AND the drill bit. It whipped around for a solid 10 seconds hanging by the bit. I couldn't believe it stayed true! But rolling it on a glass sheet showed NO deformation.

I still use that bit!
 
hi
thanks all, just a technique problem on my part i see, yes it got the heart pumping :):):):). been looking, still can't find it.

the blank i was turning at the time was one of the so crooked burls i got from psi, that i asked about in another thread. a good exercise in patience. I managed to get it to a true cylinder turning between centers as advised by someone in that thread, light light cuts, stoppping and putting thin ca on it, it kept wanting to come apart. but after all that, took more than a half hour to turn, it wasn't so much to look at anyway, very drab. not worth what i paid for it, pluse the cost of another chuck if i can't find this one :):):):)
Live and learn, thank you all again!!I really do appreciate having all of you to turn to for experience when something goes so unexpected.
Sulli
 
This has happened quite a bit on my lathe. I just turn it off once I drilled through and then pull it out once everything stopped spinning.
 
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