Author Topic: When tapping  (Read 8166 times)

Offline Toolshed

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When tapping
« on: May 11, 2016, 02:40:53 PM »
Do not use a brute drill when tapping with an adapter.   :palm:

Finally just cut flats on the bit itself and chucked that in the drill.  THAT worked!
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Offline sparky961

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Re: When tapping
« Reply #1 on: May 11, 2016, 06:43:02 PM »
It looks like you've learned something today.  In the process, you've created a nifty little piece of art to stick on your shelf too.

But I must ask, despite my better judgement: Why were you attempting to use the "adapter" (tap wrench/handle) to drive the tap instead of just chucking in the drill?

Was it perhaps due to the tap slipping in the chuck?  Your solution to put flats on the tap is certainly in my book of tricks as well - just not in chapter 1.  If all other variables are fine, a drill chuck in good condition should hold even the very hard shank of a tap with enough force to cut threads without slipping.

I'll go out on a limb and make some general suggestions:
- Make sure the hole is drilled the correct size, or even a little bigger.  Depending on material and your drill bit set, one or two sizes off can make a huge difference.
- Set up the job so that the tap remains square to the work.  Difficult if you're using a hand drill, but if you brace your arms/elbows/wrists and try to create a 2 or 3 point support system for the drill you'll have a lot more luck and break few taps.  If the tap binds, it's going to want to twist the drill out of your grasp.  Much better to have a good hold rather than the drill twisting, moving off-square, and snapping off the tap.  That said, sometimes its better to give firm support to the back of the drill and less on the handle.  That way if it does bind it can rotate a bit on it's axis and save the tap from breakage.
- Use cutting oil.  Other oils are perhaps better than nothing, but a true cutting (tapping) fluid can make a world of difference even on easy to tap materials.  Not to mention prolonging the life of your taps.

.... or maybe you just needed a few more inches of length ... :P

Offline Toolshed

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Re: When tapping
« Reply #2 on: May 12, 2016, 05:16:40 PM »
Very good points ALL.  Kinda wish I'd spent another couple semesters in metal shop to learn more about proper ways of doing tasks....

I will admit the holes may have been a bit small, since I knew I would be using the holes to bolt something that would be a spinning death dealer, I wanted to be sure they were absolutely full threads.  The chuck simply wouldn't hold the bit with enough force.

I also got about 6 holes tapped before I smacked my head and got some cutting oil (well, motor oil) and it went a lot smoother after that.
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Offline sparky961

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Re: When tapping
« Reply #3 on: May 12, 2016, 10:02:50 PM »
Trust me, you'll learn far more spending time in your own shop than in most trade schools these days. There's also plenty of information at your fingertips online but it may take some trial and error to weed out the bad advice you inevitably encounter.

It's great to see that you're also thinking about your safety. On that note, might I respectfully advise caution when using your new faceplate. Backyard cast aluminum is often brittle and of dubious strength. If applying heavy cutting force near the periphery of your plate, or spinning up a heavy part off balance, the MT shaft could easily and catastrophically fail.

As you progress with the hobby and if you find you're using this a lot, maybe consider making a version 2 out of steel. Two piece construction wouldn't be too difficult.

Offline Lew_Merrick_PE

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Re: When tapping
« Reply #4 on: May 13, 2016, 11:16:26 AM »
You might find these of use...

Offline Toolshed

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Re: When tapping
« Reply #5 on: May 13, 2016, 01:09:16 PM »
Thanks all! 

I'm not going to be putting a lot of strain on this, or do not plan to.  I rarely take more than a few thousandths at a time.  I use my lathe like an old granny would.  hahaha 

Most of what I'll be machining will be parts for Gingery machines made out of a better grade of aluminum I bought from another caster on the Alloy Avenue board.  I haven't tried machining any of that yet but it is a known alloy. 
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