A couple years ago I bought a 530-560 Accu-tapper, cheap on Ebay.... unfortunately without great instructions. I think the instructions are for someone who already knows what they are doing. The unit looks very nice and for < $25 I am willing to give it a go. I have ~ 20ea. 1/4-20 blind holes into aluminum that I thought would be a simple/good test.

I feel I need to tap the knowledge pool, OK maybe not that funny.

I tapped some test pieces with a tri-fluted tap, with light tension on the clutch it tapped all the way to the bottom, then I reversed the spindle to draw the tap out and VOILA, one threaded hole. Comments please.....instructions even better.

Glenn

You seem to be successful. Blind holes to tap in Aluminum call for thread forming taps, or you could try using a high helix tap. High helix taps are good for pushing the chip up the tap flutes and out of the hole.
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Couldn't find any pics, but sounds like a tapmatic clone. A tapmatic has a ring at the top that you screw down, 1 to 10 levels of torque. The tap pulls off the shaft to stop spinning, that's how they are supposed to be used. Then you pull up on the quill and it engages reverse inside the tapping head.

The "proper" way of using a tapmatic like head is to pull the tap out until it disengages the drive, measure how much pull out that was. Now set a stop that allows your quill to travel down (quill depth = hole depth - tap pull out length) just enough to allow the tap to disengage at the bottom of the hole. The leadscrew effect of the tap turning will pull the tap out from the head and disengage right where you want, without making the clutch do it's thing. Then you raise the quill until it engages reverse and let the tap back itself out.

For those holes you should use Spiral Flute Taps, which will lift the threads out. and for through holes in alum you should use Spiral Point Gun Taps. And, if you think that tapper is COOL you should try a Procunier!

Thanks, I just bought a couple spiral point taps this morning. I proceeded to clean up my mill, mount/true the vise and came to the realization that I need a riser to perform this op. easily. I will have to fixture my project to some angle plates (which I don't have). Then, OT - I heard a bang and all my sheep/lambs escaped from the barn and mixed with another flock so I guess machine time is over for today.

Glenn

Weedy, for BLIND holes you need Spiral FLUTE Taps, not Spiral POINT!

Since it may be a Tapmatic copy..

Tapmatic posts all of their instruction manuals on their website so you might visit threr and print some out!

Glenn