Rigid Tapping Feeds/Speeds in AL6061 - Page 3
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  1. #41
    Join Date
    Jul 2012
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    On the 1997 Fadal I worked on, until 2004, I never had machine related problems tapping, either ridged or tapping head. The installation tech said to limit rigid tapping to 2k even though it would do 3k because the spindle drive would not last, just not up to it, so that was my limit for ridged tapping. I tapped down to 00-80 with no problems in standard ER collets with decent coolant, almost all was form taps in aluminum. With form taps you should check the hole diamater the drill is drilling, size of drill just means it should be right, not that it is. I never peck tap and never have problems with deep threaded holes, even so deep I have to relieve the shank to get the thread depth. One thing I have found is it is worth getting the corect coating on the tap, which means you have to special order it. This is no big deal with Balax and only costs a dollar or so more and 1 or 2 days for chrome, which is what they suggest for 6061 aluminum. The coating really helps when you are form tapping 90-100% threads.

  2. #42
    Join Date
    Oct 2016
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    I'm lucky that my parts are aluminum. Probably makes this a lot less painful than steel.

  3. #43
    Join Date
    Oct 2005
    Wilmington DE USA
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    Followup of my earlier post.
    I had planned on replacing the spindle drive belt during Christmas break.
    Ran a test at 2000rpm for 1/4-20 F100.00 with a floating holder, form tap(new) and got good results
    2nd hole into the 18" square plate the tap attempts to become part of the plate.
    Feed hold won't work in tapping mode, aw shit, hit the big red button.
    Was able to remove the tap without breaking it, the "hole" came out with the tap.
    Customer allowed a thread insert for the one hole, finished out the tapping on the manual mill

    Last weekend became belt change time.
    I had ordered (using the manufacturers manual for a part# ) a belt 3 months ago in preparation as it was a 3 week lead.
    Saturday morning turn on the radio, fresh pot of coffee, no one to bug me, dig into the spindle and find out the belt I ordered wasn't evan close. (it did match what I ordered, the machine builders fault.)
    Lucked out and was able to measure the old belt, found 2 on ebay , nos, and reassembled today.
    Set up a test tap 33 holes in 1/2" 6061 using the S2000/F100, all 33 holes look great

    So if your having problems with tapping and everything else has been ruled out, check your spindle belt.
    Unless you have a gear drive.

    The slippage I was getting at reversing was enough to throw off the balance between the holder extending/floating a little and the limit

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