# What is a draw bar?



## TomC (Oct 27, 2008)

What is a draw bar and why would you need one? I Was watching a video on bottle stopper turning and Capt Eddie said you need to use a draw bar with the mandrel. I had just turned a bottle stopper with a mandrel and did not use one. 
Tom


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## Dave Paine (May 30, 2012)

A draw bar is normally used to "drift" i.e. knock out a morse taper.

Capt'n Eddie was presuming the mandrel had a morse taper and that during use it was not a simple pull to extract.

I normally use my scroll chucks and attachments, so I rarely have a morse taper in the headstock.

I use a morse taper in my tailstock all the time, either a live centre or a Jacobs chuck with a morse taper.

I can tell the difference in quality. The live centre was made by Oneway. This comes out without much force. The Jacobs chuck needs a hard knock to remove.


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## duncsuss (Aug 21, 2009)

I understood it to be the opposite, Dave :huh:

To me, a draw bar is a length of threaded rod that you feed through the hole in the drive shaft and screw into a threaded hole in the end of the mandrel.

Then screw a nut onto the outboard end of the threaded rod and tighten it up as a way of locking the mandrel to the head stock.

I hope one of us is right :laughing:


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## TomC (Oct 27, 2008)

duncsuss said:


> I understood it to be the opposite, Dave :huh:
> 
> To me, a draw bar is a length of threaded rod that you feed through the hole in the drive shaft and screw into a threaded hole in the end of the mandrel.
> 
> ...


That's kind of what I thought as I had seen statements that the end is threaded for a draw bar. I still don't know why you would need one? Is it to make sure the taper is seated? I don't need one with my drive center. Confused!!!
Tom


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## Dave Paine (May 30, 2012)

duncsuss said:


> I understood it to be the opposite, Dave :huh:
> 
> To me, a draw bar is a length of threaded rod that you feed through the hole in the drive shaft and screw into a threaded hole in the end of the mandrel.
> 
> ...


One of us is definately right. :laughing:

I think it is you. I was confusing with knock-out bar. :huh:

I now remember my mandrel is tapped for a drawbar. I have not needed to use it since I mount the mandrel in my scroll chuck.


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## Alchymist (Jan 2, 2011)

A drawbar is just what the name says - a threaded bar to "draw" collets and other accessories into a tapered recess on a machine spindle. Second picture shows drawbar, collets, and the knockout bar. In many cases a knockout bar is not used, the drawbar is loosened, then tapped to unseat the collet or other accessory. Drawbars are not used in all cases, typically like the tailstock of a lathe - tapered recess,friction hold.


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## duncsuss (Aug 21, 2009)

TomC said:


> That's kind of what I thought as I had seen statements that the end is threaded for a draw bar. I still don't know why you would need one? Is it to make sure the taper is seated? I don't need one with my drive center. Confused!!!
> Tom


Again, my understanding ... there's no need for a drawbar if you're working on a spindle and the far end is supported by the tailstock.

However, I've got a MT2 mandrel with a cloth buffing wheel on it.
With nothing holding the mandrel into the headstock except friction, it has worked loose while I'm buffing bowls (I guess a combination of the drag as it buffs plus occasional force tending to pull it out of the drive shaft.)


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## TomC (Oct 27, 2008)

duncsuss said:


> Again, my understanding ... there's no need for a drawbar if you're working on a spindle and the far end is supported by the tailstock.
> 
> However, I've got a MT2 mandrel with a cloth buffing wheel on it.
> With nothing holding the mandrel into the headstock except friction, it has worked loose while I'm buffing bowls (I guess a combination of the drag as it buffs plus occasional force tending to pull it out of the drive shaft.)


OK, that make sense with on tailstock pushing on the head stock. I did most of my stopper between centers. I only move the tailstock to complete the top.
Tom


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## sawdustfactory (Jan 30, 2011)

Don't want to hijack this thread, but Dave why are you having to knock tapers out of your tailstock? Mine automatically eject when I retract the tailstock all the way.


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## duncsuss (Aug 21, 2009)

sawdustfactory said:


> Don't want to hijack this thread, but Dave why are you having to knock tapers out of your tailstock? Mine automatically eject when I retract the tailstock all the way.


Some do, some don't ... the same live center auto-ejects on my HF lathe but doesn't on my Nova.


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## Dave Paine (May 30, 2012)

sawdustfactory said:


> Don't want to hijack this thread, but Dave why are you having to knock tapers out of your tailstock? Mine automatically eject when I retract the tailstock all the way.


I wish my lathe worked this way, but sad to say it is a "manual" process for me. :thumbdown:

The darn Jacobs chuck sticks and drilling does not exert a lot of force.


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## Woodwart (Dec 11, 2012)

That's a feature found on some lathes and not on others. Mine, for instance.


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## TomC (Oct 27, 2008)

sawdustfactory said:


> Don't want to hijack this thread, but Dave why are you having to knock tapers out of your tailstock? Mine automatically eject when I retract the tailstock all the way.


I Turned my stopper between centers and put the mandrel in the tailstock to thread the stopper. I went to eject the mandrel by turning the wheel and it would not eject. First time this has happened on this lathe. I had to use a knock out bar to remove it. Upon looking at my mandrel it is shorter than all my other Morris tapers. That is why it would not eject.
Tom


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## joek30296 (Dec 16, 2009)

TomC said:


> I Turned my stopper between centers and put the mandrel in the tailstock to thread the stopper. I went to eject the mandrel by turning the wheel and it would not eject. First time this has happened on this lathe. I had to use a knock out bar to remove it. Upon looking at my mandrel it is shorter than all my other Morris tapers. That is why it would not eject.
> Tom


Tom...My Woodcraft live center was too short, like yours, to self-eject when turning the tailstock in reverse. I was able to fix it though. The end is tapped for a 10-32 screw. I found a couple of washers about the same diameter as as the end of the mandrel and screwed them in place. That just lengthened the mandrel enough so that it now self-ejects properly.


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