Power drawbar


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Thread: Power drawbar

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    Member popspipes's Avatar
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    Default Power drawbar

    I have an 1100 with a power drawbar and would like to limit the distance the collet lowers so that it will still release but not protrude as much from the spindle nose if that makes any sense??

    any thoughts, views or insight appreciated.....................

    Similar Threads:
    mike sr


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    Member kstrauss's Avatar
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    Default Re: Power drawbar

    I assume that the 1100 PDB is very similar to the 770 one, If so, adjusting the protrusion of the bolt from the pneumatic cylinder should allow controlling how far the collet stick out. I'm curious though. Why do you care?



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    Default Re: Power drawbar

    Quote Originally Posted by kstrauss View Post
    I assume that the 1100 PDB is very similar to the 770 one, If so, adjusting the protrusion of the bolt from the pneumatic cylinder should allow controlling how far the collet stick out. I'm curious though. Why do you care?
    I like to wipe the spindle nose between tools with my hand and its hard to do with the collet protruding thru a bit and I like to seat the tool and rotate the holder a bit just to insure a good seat against the spindle nose, just force of habit I guess, no reason otherwise.

    mike sr


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    Default Re: Power drawbar

    How much can you expect?
    My bell view washer stack of 8 allows what looks like 1/8-1/16 of an inch of total movement at most in the pdb.



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    Default Re: Power drawbar

    Quote Originally Posted by mountaindew View Post
    How much can you expect?
    My bell view washer stack of 8 allows what looks like 1/8-1/16 of an inch of total movement at most in the pdb.
    mine sticks out 1/8" or more in the release position, the tts holders dont touch the spindle nose when inserted when the pdb is in the release position. I just like to seat the holder and rotate it back and forth slightly to theoretically make a good seat of the tool holder (just a habit) maybe not necessary though. I think I need to tighten the drawbar a bit as I only have a 4 set stack of bellevilles, I notice the new machines have an 8 set stack, I like that as there would be less flex on the bellevilles for the same travel??

    Parts business has slowed down, time to work a bit on the machine ha!

    mike sr


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    Default Re: Power drawbar

    I shortened the Tormach collet, it doesnt protrude now, we shall see how it works out, I have a new Lydex just in case this wasnt one of my better ideas ha!

    I want to make a new power drawbar nut and split it so that I can tighten/clamp it on the threads, it was loose again, that setscrew doesnt work all that well. My theory is that a split nut will work much better in that regard, the factory nut has a very sloppy thread and just wont stay tight.

    another idea is a seal for the bottom of the spindle to keep coolants out of the lower spindle bearing. I think mounting it to the spindle nose may be challenging....

    mike sr


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    Default Re: Power drawbar

    Quote Originally Posted by popspipes View Post
    another idea is a seal for the bottom of the spindle to keep coolants out of the lower spindle bearing. I think mounting it to the spindle nose may be challenging....
    I recall seeing the suggestion (maybe from Keen?) that rather than attempting to seal the bearing just put a plastic disk on the tool and it will sling off the coolant before it can get into the bearing.



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    Default Re: Power drawbar

    Quote Originally Posted by kstrauss View Post
    I recall seeing the suggestion (maybe from Keen?) that rather than attempting to seal the bearing just put a plastic disk on the tool and it will sling off the coolant before it can get into the bearing.
    I made one of those a few years back, and it works fine, I used UHMW and put an oring on the outside rim so I could turn the spindle by hand with it I was just thinking high pressure coolant would or could get into it possibly, just a thought...........

    I think the new M machines have a seal on the bottom of the spindle housing.

    mike sr


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    Member nitewatchman's Avatar
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    Default

    I have had my PDB for quite a while. When I received it, I noticed the thread fit on the spindle flange nut was very loose. Loose to the point that I felt it might strip when it was tightened. Even with the set screw tight, it would loosen sometimes to the point of spinning off and locking up the spindle when stopping from high speed.

    Out of frustration I bought a replacement nut from Tormach. The new nut fit was very good, a tight hand fit all the way down. After that no more problems.

    I believe the first nuts were defective and the threads were yielded and stretched by the PDB and impossible to keep tight. Anyway problem solved.

    Quote Originally Posted by popspipes View Post
    I shortened the Tormach collet, it doesnt protrude now, we shall see how it works out, I have a new Lydex just in case this wasnt one of my better ideas ha!

    I want to make a new power drawbar nut and split it so that I can tighten/clamp it on the threads, it was loose again, that setscrew doesnt work all that well. My theory is that a split nut will work much better in that regard, the factory nut has a very sloppy thread and just wont stay tight.

    another idea is a seal for the bottom of the spindle to keep coolants out of the lower spindle bearing. I think mounting it to the spindle nose may be challenging....




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    Default Re: Power drawbar

    Quote Originally Posted by nitewatchman View Post
    I have had my PDB for quite a while. When I received it, I noticed the thread fit on the spindle flange nut was very loose. Loose to the point that I felt it might strip when it was tightened. Even with the set screw tight, it would loosen sometimes to the point of spinning off and locking up the spindle when stopping from high speed.

    Out of frustration I bought a replacement nut from Tormach. The new nut fit was very good, a tight hand fit all the way down. After that no more problems.

    I believe the first nuts were defective and the threads were yielded and stretched by the PDB and impossible to keep tight. Anyway problem solved.
    Thanks for the heads up! Mine is a 2012 model and has a very sloppy thread.

    mike sr


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    Member nitewatchman's Avatar
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    Default

    Quote Originally Posted by popspipes View Post
    Thanks for the heads up! Mine is a 2012 model and has a very sloppy thread.
    Mine is about the same vintage. I lived with it for years.



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    Default Re: Power drawbar

    Quote Originally Posted by nitewatchman View Post
    Mine is about the same vintage. I lived with it for years.
    I looked for one on the parts section of the Tormach.com website, found lots of parts but no pdb nut.
    I called them today, got to talk to a lady, got a case number and I asked when I could expecct a call back, she said turnaround on calls is 24 hours.

    mike sr


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    Default Re: Power drawbar

    Brian from Tormach called back in an hour or so, they are sending me a new PDB flange nut for the spindle.

    mike sr


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    Default Re: Power drawbar

    Quote Originally Posted by popspipes View Post
    Brian from Tormach called back in an hour or so, they are sending me a new PDB flange nut for the spindle.
    What are you guys talking about?
    My machine has a pdb rod with flange then bellview stack slid thru spindle to the tts r8 holder, No nuts
    I just replaced the entire assembly pdb,washers and r8collet this time last year. I stored old in a drawer in case of need.



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    Default Re: Power drawbar

    MD the flange nut on top of the spindle, about 3" in diameter at the top of the spindle that the PDB pulls up on to release the collet. It is a large nut probably 4 or 5 pounds that screws onto the top spindle thread, when that thing is out of balance at high rpm you will know it thats for sure.

    mike sr


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    Default Re: Power drawbar

    Quote Originally Posted by popspipes View Post
    MD the flange nut on top of the spindle, about 3" in diameter at the top of the spindle that the PDB pulls up on to release the collet. It is a large nut probably 4 or 5 pounds that screws onto the top spindle thread, when that thing is out of balance at high rpm you will know it thats for sure.
    Ahh, guess I needed a picture
    I had that come lose right after I setup the machine years ago. Made me check the entire machine before I used it for months. Was afraid of machine damage from something stupid that I assembled or from the maker.



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    Default

    I should have called! Mine was SIGNIFICANTLY more than free.

    gary

    Quote Originally Posted by popspipes View Post
    Brian from Tormach called back in an hour or so, they are sending me a new PDB flange nut for the spindle.




  18. #18

    Default Re: Power drawbar

    I had a local engine builder balance the motor, spindle and spindle nut.

    https://tormachpcnc1100series3.blogs...y-balance.html

    I also purchased Gary's (nitewatchman) motor fan kit, to remove the stock motor fan

    David



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    Default Re: Power drawbar

    Flange nut is installed, I cross d/t the lower portion 5 mm x .8 and split it in the saw about 75% of the way thru so that it would compress on the threads, worked out well. I also static balanced it on my set of hard drive bearings and drilled the heavy spot out of the upper flange, the machine still had some vibration so I put my eccentric rings on and balanced with those, it is not perfect but close.

    That nut coming loose is history now .................

    mike sr


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