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How to really screw up a lathe.....

Discussion in 'Tutorials and Tips' started by underdog, Nov 30, 2005.

  1. underdog

    underdog

    Joined:
    Oct 5, 2005
    Messages:
    451
    Location (City & State):
    North Georgia
    1) When turning blanks between centers, don't remove the drive center, just hammer the blank on to the drive spur. This will impact the headstock bearings and shorten their life.

    2) When trying to keep the blanks from slipping, overtighten the tailstock ram. This will preload the headstock bearings and also shorten their life.

    3) Use a long extension cord and run the lathe at top speed while turning agressively. Don't ease up if it slows the lathe down. It makes it easier if you use dull tools. This will overheat the motor because the resistance of the circuit is too great and you've also overloaded it.

    4) Don't clean off the lathe after each use. If the lathe is a mini, chances are the chips will build up in front of the motors cooling fan because the tool rest is right above the intake. Oh yeah.. it will overheat then.

    5) Teach yourself how to use a skew. This way you will have plenty of catches and run that newly sharpened HSS tool into your drive center, tailtock center, or.. even better, the spindle threads.

    6) If there's a slight chance you might damage a lathe during any procedure, then borrow a friends lathe. It will ensure that something will break. Murphy's law and all that don'tchaknow.


    Now in case you think I'm being overly sarcastic....

    Yeah. I learned most of these things the hard way. :eek:

    After I realized a few problems, I reviewed all my habits, and made some policy changes.

    1) Now the drive spur comes out and gets tapped into the blank.

    2) I tighten the tailstock till all centers are engaged and then back off til the piece slips, then tighten until it won't slip. Adjust as needed during turning.

    3) Nick Cook pointed out Monday at our club meeting, that he was turning at a step down from top speed because I had him on an extension cord on a mini lathe. So I then realized I had done this before and decided to follow his advice. I will not turn at top speed if a lathe is on an extension cord. I've always paid attention to motor speed and back off if it slows down, but now I'll be even more sensitive in this kind of situation.

    4) I once let the chips build up til it covered the motor (I think this was all in one session...) but now I pay attention to the fan intake. I also vacuum/blow the lathe off after each use. I pay special attention to the motor since I burned up a capacitor once by overheating the motor with a combination of this problem and the preceding one (extension cord).

    5) I'm also grateful to Nick for showing us the basics of using a skew (or at least one way to use them). I realize the value of some foundational teaching as well. I had determined that I probably wouldn't pay for any lessons since I don't have lots of money, but I realize that tutoring would advance my skills quickly. It also helps save a lot of sharpening sessions, screwed up projects, and cut up centers and spindles... :(

    6) And if there's the least chance that I think I might just possibly damage someone else's lathe or tool, I'm not gonna borrow it. Period. Luckily my friend was very understanding. I got the requisite ribbing of course, but he didn't curtail the relationship because of it. It probably helped that I replaced the bearings in the motor as well as the capacitor too.


    Well, hope this helps you. I'm sure you can come up with some more things that will break your lathe, but this should get you started. Better yet, break your friends lathe...
     
    Last edited: Nov 30, 2005
  2. Redfish

    Redfish

    Joined:
    May 13, 2005
    Messages:
    121

    You're doing it the hard way if you have something that's slipping. For spindles I use the bandsaw to cut a 1/4" deep kerf dead center of the blank, flip the blank 90", cut another kerf forming a cross-hare. Shoot a 1/8 hole in the center with a drill and stick the blank between centers. Holds like a ticked off octopus.

    For larger blanks like bowl blanks I use a dremel and a carbide disk to hog out the cross-hares. You do have to have a kung-fu grip on the dremel but it works.
     
  3. JimQ

    JimQ

    Joined:
    Aug 30, 2005
    Messages:
    134
    Location (City & State):
    Glendale, AZ
    Don't even need the Dremel. Just hit a couple of times with a sharp chisel & mallet.

    JimQ
     
  4. Utuk_Xul

    Utuk_Xul

    Joined:
    Nov 16, 2005
    Messages:
    5

    I've split a few good blanks that way. :(
     
  5. JimQ

    JimQ

    Joined:
    Aug 30, 2005
    Messages:
    134
    Location (City & State):
    Glendale, AZ
    I hit it at a 45 degree angle to the grain, and I don't hit it that hard.

    JimQ
     
  6. underdog

    underdog

    Joined:
    Oct 5, 2005
    Messages:
    451
    Location (City & State):
    North Georgia

    Eh? Sounds like a lot more work than popping the drive center out with the knockout rod which is right there on the lathe, and popping it with the mallet, which sits on the lathe bench...

    Instead you recommend walking over to the band saw and cutting, and then finding a drill or drill press and drilling? Yeah it might hold good, but for 12 inch scrap spindles, it sounds like more work than my method...

    Or, even better, get a dremel tool and carbide disk (both of which I'd have to purchase) that it takes a King Kong grip to cut? :eek:

    Who's doing more work here? :p

    I've tried the bandsaw method and drill method before and it works fine, it's just quicker to smack the center into the wood with a mallet.

    I think we can all agree with my main point, which is merely that it's better not to hammer your headstock bearings...
     
  7. FlyingScooter

    FlyingScooter

    Joined:
    Jan 13, 2006
    Messages:
    2
    Been there, done lots... ;) it got better!

    My excuse is: It's like TV logic, honey.
    If the TV don't work, doesn't everyone lovingly caress it with a ballpene hammer?

    I've been guilty of those many times.
     

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