Where did I go wrong??

[suefox51]

I've been drilling on the lathe for a short while. I purchased a keyless chuck and have the PSI blank holder.
While drilling a maple blank yesterday, the blank exploded, the blank holder got chewed up by the drill bit and the keyless chuck flew off and hit me in the shoulder.
I realize I should have been wearing Kevlar, but didn't have it available.

Is there something I missed? They keyless chuck slides into the tailstock and tightens up in there, but, and this may be the key, sometimes, it loosens up while drilling.

Any and all information, input, suggestions, don't ever do this again's, will be appreciated. Really got beat up by that chuck - only slightly cut by the flying drill bit that was still in the chuck - which, by the way, ended up with a bang on the garage concrete floor and is bent now - jeez.....

Thanks,
Sue:frown:

 

[jttheclockman]

Is it a 2 piece jacobs chuck like this??? What actually came off. Did you seat the taper deep enough into the tailstock?? Sometimes you need to clean them out. What cused the blank to blow up?? Did the bit wobble because the chuck was loose??? Need some more info.

 

[mike4066]

Sounds like the drill chuck came out of the tailstock, or came apart as JT's image shows.

I had a similar thing happen a few weeks ago. I was using a parabolic bit and when the drill bit was exiting the back of the blank it pulled the chuck out of the tailstock.

 

[thewishman]

OUCH!

I almost always keep a hand on the drill chuck while drilling. Some materials are grabbier than others and the jacobs chuck can get pulled out of the tailstock.

I usually drill at less than 1000 rpms and don't put much pressure on the drill bit. I want it to work its way into the blank, not be forced into it.

Can you give us an idea about the speed and the size and type of bit you were using?

 

[stonepecker]

I ALWAYS hold on to the drill chuck when backing out the drill bit. It has never happened to me (Thank God) but I did see when a friend was backing the drill out the bit started to wobble. I reached over and killed the power. If the bit had caught ....things then start to fly. I read this someplace else and realized that even a face shield doen't help when large hunks of metal start flying at fast speeds.

Hopefully, you were not seriously hurt.

JT is right......more information would be helpfull. But this is the first thing I hear most often. People forget to hold that drill and chuck into the tailstock tight, when backing out.

Any pictures? They are always a help.

 

[suefox51]

Same chuck as JT showed - chuck came off the taper - I wasn't backing out, I was drilling in - I'm thinking that perhaps the bit got too hot? I sprayed between drillings, but this maple seemed harder than the first ones I did - of course that could also mean the bit was duller! I will take photos of damage (to equipment, not me)! Not seriously hurt, just really bruised!
Thanks for the input all!

Sue

 

[southernclay]

Glad you are ok Sue, that is scary.
I think it's been covered but here's what works for me.
-500 RPM
-Sharp bits
-Hand on the Jacob's chuck
-Back out often to clear chips and let cool if needed

I don't personally spray water when using wood, I have before with acrylics. You can take an empty squirt bottle and squeeze it near the hole to help cool things down if you are concerned with heat build up. I did my first casein pen recently and did it dry, drilled very slow, backed out and let it cool often and worked out great. On the other hand I recently did 12 pens out of Willow and drilled through them super fast and just used my hand to push the tailstock through the material only backing out a couple of time and it worked out great. The first 3 of 4 items stayed the same on that material though.

Again glad you are ok, keep at it and have fun!

 

[D.Oliver]

To keep my chuck from coming loose, I use an 8-9" piece of 1/4" all thread. I put the chuck in the morse taper, insert the all thread from the opposite side (where you insert your knock out bar) and then tighten it down with a wood disk that has a nut epoxied into it. That will keep the morse taper seated. It won't help the chuck from coming loose from the mores taper though.

 

[jttheclockman]

Same chuck as JT showed - chuck came off the taper - I wasn't backing out, I was drilling in - I'm thinking that perhaps the bit got too hot? I sprayed between drillings, but this maple seemed harder than the first ones I did - of course that could also mean the bit was duller! I will take photos of damage (to equipment, not me)! Not seriously hurt, just really bruised!
Thanks for the input all!

Sue

Sue when you say it came off the taper. Which taper??? Did the whole thing (both pieces) come out together from the tailstock or did the chuck come off the spindle???

If the entire chuck came out of the tailstock then try to do as others have suggested, as you drill just hold onto the chuck as you drill and also as you pull the drill bit out. If the drill spun on you as you were drilling there is no way that chuck should have come out of the taper. It would just spin and you need to watch that it does not mar up the inside of the taper. Usually as you drill that taper seats itself even tighter in the tailstock. It comes loose when you pull the bit out of the piece you are drilling. As mentioned need to check that the taper is clean both on the tailstock and the chuck shaft. Also make sure that chuck is seated tight in the taper. very easy to have the tailstock run up too far.

 

[Smitty37]

I've been drilling on the lathe for a short while. I purchased a keyless chuck and have the PSI blank holder.
While drilling a maple blank yesterday, the blank exploded, the blank holder got chewed up by the drill bit and the keyless chuck flew off and hit me in the shoulder.
I realize I should have been wearing Kevlar, but didn't have it available.

Is there something I missed? They keyless chuck slides into the tailstock and tightens up in there, but, and this may be the key, sometimes, it loosens up while drilling.

Any and all information, input, suggestions, don't ever do this again's, will be appreciated. Really got beat up by that chuck - only slightly cut by the flying drill bit that was still in the chuck - which, by the way, ended up with a bang on the garage concrete floor and is bent now - jeez.....

Thanks,
Sue:frown:

Sue, Whatever other advice you get -- Keyless or otherwise, always hold the chuck when drilling with the lathe. In this particular case...a number of things could have happened but if you were holding the chuck you would have been able to stop the lathe before the chuck got thrown.

 

[monophoto]

Sounds exciting!

The fact that pieces and parts were flying everywhere suggests a fundamental problem - what lathe speed were you using?

When drilling, you should be using a very low speed - for most lathes, the lowest speed possible. And you should be periodically backing the bit out of the blank to clear the swarf. If you drill at high speed, or fail to remove the swarf, you will get additional friction that leads to additional heating, and heating can cause the blank to crack, especially if it contains moisture. On the other hand, if you are drilling at a nice slow speed, if something bad happens, the pieces nd parts just drop to the top of the bench - they won't be thrown around the shop.

Question 2: where did the failure start? If I understand correctly, the blank failed, and then everything else went bad. What kind of blank - wood or plastic? That does sound like a heat-related problem.

As others have said, it is wise to grip the jacobs chuck with your left hand while drilling - that's mainly to keep the taper from backing out of the tailstock and to keep the chuck body from backing of the jt33 taper in its arbor. But holding the chuck also prevents the chuck from rotating which is the first step in the process of the chuck coming off the arbor.

Finally, you said that the blank holder was damaged. That sounds like you were forcing the bit into the blank, and when the blank failed, the tailstock-mounted chuck jumped forward into the blankholder. NEVER force a drill bit! Let the rotation of the blank against the bit cut the hole, and then gradually advance the bit into that hole. Forcing the bit increases the heat due to friction. And it also can cause the bit to wander off axis and potentially come through the side of the blank.

And yss, if the bit is dull it can be a problem. In fact, a dull bit can be dangerous. The bits are are used to drill pens are large enough that you can easily tune up the cutting edge using a diamond paddle.

The rules for successful drilling are:
1. Use sharp bits. If the bit is dull, take a few seconds to tune up the cutting edge.
2. Use a very low speed - 200-600 r/min.
3. Clear the swarf frequently
4. Advance the bit into the wood very slowly - allow the bit to cut a hole before pushing the bit into the hole.

 

[suefox51]

Thanks to all of you for the information - I was drilling at a fast speed, clearing out the swarf, but not too frequently - you all nailed the issues on the head - I'll go much slower now, once I replace what needs to be replaced!
You all rock with all the great information and instructions!

Sue

 

[jeff]

To keep my chuck from coming loose, I use an 8-9" piece of 1/4" all thread. I put the chuck in the morse taper, insert the all thread from the opposite side (where you insert your knock out bar) and then tighten it down with a wood disk that has a nut epoxied into it. That will keep the morse taper seated. It won't help the chuck from coming loose from the mores taper though.

How are you able to advance the quill? Unless that is elastic all-thread...

 

[jttheclockman]

To keep my chuck from coming loose, I use an 8-9" piece of 1/4" all thread. I put the chuck in the morse taper, insert the all thread from the opposite side (where you insert your knock out bar) and then tighten it down with a wood disk that has a nut epoxied into it. That will keep the morse taper seated. It won't help the chuck from coming loose from the mores taper though.

How are you able to advance the quill? Unless that is elastic all-thread...

I get your point Jeff and i was hoping he takes it off before drilling and it is used to secure the taper. Or maybe he does have something we have never seen.:biggrin::biggrin:

 

[Ed McDonnell]

If you drill by sliding the whole tailstock, rather than cranking the quill in and out a drawbar (what Derek described) will work fine. Of course, a loose tailstock during drilling can cause other problems (especially if self feeding is a possibility). It's not for me, but some really talented turners in my area think I'm crazy for cranking the tailstock to drill.

Clean tapers, reasonable drilling speed and feed, sharp bits that have been tuned for the material to stop self feeding will help eliminate a lot of the potential excitement of drilling on the lathe.

Ed

 

[TonyL]

I not only hold the chuck, but set lock the tailstock lock lever as the drill just leaves the barrel. I don't know if that helps, but it do it. I think using a draw bar would be the safest thing to do. I am surprised that all do not use drawbars (I don't, but I did buy the stuff to make one!).

 

[mg_dreyer]

I always use a drawbar. Mine is simply held in with a washer and a nut. Derek is correct.

 

[jttheclockman]

The one thing that needs to be noted in this type of chuck there are 2 morse tapers on the j33 arbor so a draw bar will only help to a point.

 

[Curly]

The one thing that needs to be noted in this type of chuck there are 2 morse tapers on the j33 arbor so a draw bar will only help to a point.

Small correction John. One Morse taper, the long one and the short one being one of the "j" or other series tapers.

Sue. When you're ready to put the taper into the chuck make sure it is not galled or scored and still straight, otherwise get a new one. Wipe the two taper surfaces clean with solvent, acetone will do, and put them together holding the chuck up and the arbor down. Tap them on a bench and then slam them hard once or twice on the bench so the inertia of the chuck stopping seats it. That should keep them together in the future. Tapers come loose from vibration so keeping a steady force on the taper keeps them locked in place. That's why so many are recommending holding the chuck while drilling.

 

[jttheclockman]

Basically there are 2 tapers. One short and one long. To really lock the short taper to the chuck you can use the old adage heat and cold expand and contract metals. Stick the arbor in the freezer for about an hour and that will shrink the metal. Now you can get crazy and heat the chuck but I would frown on that because of the lube in it. Take the arbor out of the freezer and insert in chuck and hit it with a brass hammer or a piece of wood and a dead blow hammer. Have the chuck resting on a piece of hardwood. This will lock the arbor to the chuck. One less thing you have to worry about coming loose.

As you are inserting the taper into the tailstock give it a twist on that final push.

 

[LouF]

I had my Drill chuck fly out of the tail stock it flew across my 3 car garage and hit my wife's golf cart scared the C**P out of me.:frown:

 

[suefox51]

Got back in the saddle again (so to speak) - drilled on the lathe on a slow speed, cleaning the bits on the drill bit and all was well!
Thanks to everyone for their input!!

Sue

 

[farmer]

Flying stuff

I had my Drill chuck fly out of the tail stock it flew across my 3 car garage and hit my wife's golf cart scared the C**P out of me.:frown:

I was making manzanita burl wood dowels with a live cutter ( router 30.000 rpms ) and the piece in my lathe came loose and the router got a big hunk of wood a blew the piece of wood apart there was zero time to react.

I considered my self blessed that I didn't get hit,one piece about the size of a golf ball flew by my head.

 

[LouF]

I had my Drill chuck fly out of the tail stock it flew across my 3 car garage and hit my wife's golf cart scared the C**P out of me.:frown:

I was making manzanita burl wood dowels with a live cutter ( router 30.000 rpms ) and the piece in my lathe came loose and the router got a big hunk of wood a blew the piece of wood apart there was zero time to react.

I considered my self blessed that I didn't get hit,one piece about the size of a golf ball flew by my head.

That is a very close call there.