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There are two ways to drill on the lathe. To make sure I understand the situation, I believe you said:

The blank is held in a scroll chuck mounted on the headstock spindle. The Jacobs chuck holding the drill bit is mounted in the tailstock morse taper. And the problem is that when the hole gets about 1/4" deep, the blank 'grabs' the wood - which means that the Jacobs chuck starts spinning in the tailstock. And then if you try to back the tailstock away, the bit remains captured in the blank and the Jacobs chuck slips out of the tailstock taper.

That's a very common problem. The solution is simply to grasp the Jacobs chuck with your left hand as you advance the tailstock ram with your right hand. The cause of the problem is that your Jacobs chuck isn't firmly seated into the Morse taper in your tailstock . Some Jacobs chucks are designed with a second taper - a JT33 - that fits into a matching taper inside the body of the Jacobs chuck - that just gives you a second taper that can slip, and twice the chances of the problem happening. In either event, the solution is the same - grasping the body of the Jacobs chuck will prevent it from spinning. And if you hold the Jacobs chuck you can also push it slightly toward the tailstock as you back the bit out of the wood to prevent breaking the seating of those tapers.

Louie

<blockquote data-quote="Louie_Powell" data-source="post: 87886" data-attributes="member: 602">There are two ways to drill on the lathe.&nbsp; To make sure I understand the situation, I believe you said:&nbsp;The blank is held in a scroll chuck mounted on the headstock spindle.&nbsp; The Jacobs chuck holding the drill bit is mounted in the tailstock morse taper.&nbsp; And the problem is that when the hole gets about 1/4&quot; deep, the blank &#039;grabs&#039; the wood - which means that the Jacobs chuck starts spinning in the tailstock.&nbsp; And then if you try to back the tailstock away, the bit remains captured in the blank and the Jacobs chuck slips out of the tailstock taper.That&#039;s a very common problem.&nbsp; The solution is simply to grasp the Jacobs chuck with your left hand as you advance the tailstock ram with your right hand.&nbsp; The cause of the problem is that your Jacobs chuck isn&#039;t firmly seated into the Morse taper in your tailstock .&nbsp; Some Jacobs chucks are designed with a second taper - a JT33 - that fits into a matching taper inside the body of the Jacobs chuck - that just gives you a second taper that can slip, and twice the chances of the problem happening.&nbsp; In either event, the solution is the same - grasping the body of the Jacobs chuck will prevent it from spinning.&nbsp; And if you hold the Jacobs chuck you can also push it slightly toward the tailstock as you back the bit out of the wood to prevent breaking the seating of those tapers.Louie</blockquote>

[QUOTE="Louie_Powell, post: 87886, member: 602"] There are two ways to drill on the lathe. To make sure I understand the situation, I believe you said: The blank is held in a scroll chuck mounted on the headstock spindle. The Jacobs chuck holding the drill bit is mounted in the tailstock morse taper. And the problem is that when the hole gets about 1/4" deep, the blank 'grabs' the wood - which means that the Jacobs chuck starts spinning in the tailstock. And then if you try to back the tailstock away, the bit remains captured in the blank and the Jacobs chuck slips out of the tailstock taper. That's a very common problem. The solution is simply to grasp the Jacobs chuck with your left hand as you advance the tailstock ram with your right hand. The cause of the problem is that your Jacobs chuck isn't firmly seated into the Morse taper in your tailstock . Some Jacobs chucks are designed with a second taper - a JT33 - that fits into a matching taper inside the body of the Jacobs chuck - that just gives you a second taper that can slip, and twice the chances of the problem happening. In either event, the solution is the same - grasping the body of the Jacobs chuck will prevent it from spinning. And if you hold the Jacobs chuck you can also push it slightly toward the tailstock as you back the bit out of the wood to prevent breaking the seating of those tapers. Louie [/QUOTE]

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