how to use a tapping head

Last week I went to a local machinery auction and for once there were more lots than interested bidders. I bid and won a bench grinder for
$5, the auctioneer included the two prior lots that did not sell for $5. One of those two lots consisted of an antique tapping head. The brand name is ETTCO, Eastern Tube & Tool Co. w/ a patent lable of Aug 1924. I have never used a tapping head before - I have occasionaly tapped using my Bridgeport w/ a tap in a collet. In playing with the tapping head by hand, I have been able to make it reverse direction but I am unsure of exactly what makes it change direction - is it torque based or is it when the unit receives an axial load (tap botomed out)? Do tapping heads typically have any adjustments? THere are a couple of set screws that might be intended for ajustment but there are no markings on the body nor any indication that there has been frequent adjustments made to these set screws.
BTW, a mini gloat. I had 6 winning bids, all of them bottom feeder types for odd lots. One of them was for a box or boring bars for $5 (there was only one bar in teh lot that I could use on my 12x36 Clausing. I resold the boring bars the next day. As I was loading stuff into my vehicle to the people that bought the huge Monach lathe for $100 (no joke!) came by and offered me $30. I bought a lot of misc electical for $5. The lot consisted mostly dirty extension cords. Under the pile of cords was a small, 1.2A Dumore hand grinder - that works good!
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The ones I have seen reverse direction when the axial pressure on the top changes direction from downfeed to upwards, so that you can forward and reverse by pulling up or down on the drill press quill feed handle... --Glenn Lyford
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Without being familiar with that particular tapping head, I'm not sure there are any direct answers. Some tapping heads rely on the operator to not break taps, others have adjustments that limit driving force. As has already been suggested, when tapping, all you have to do is lift up on the quill feed handle and the tapping head reverses, usually at a greater speed than the tapping speed, so you can get out of a hole very quickly. Best way to learn how to use yours if you have no literature on which to call for information is to get your hands dirty on a practice piece that has little to no value to you. You'll probably find you can still break taps, it just makes it faster to do so. <g>
Make sure you use taps intended to be power driven. The typical hand tap will usually lead to nothing but broken taps because they rely on reversal constantly to break the chips. Nothing taps quite as well as a gun tap, even in blind holes. Just make sure you have enough depth of hole to accommodate the chip, which can usually be removed after tapping by using a needle in an air hose nozzle. I keep several sizes of them in my toolbox for just such an occasion. It's also a good idea to use only sharp taps. Once they are dull, they usually lead to trouble, and are difficult to re-sharpen with good results. Most attempts generally fail miserably.
Harold
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Harold & Susan Vordos wrote:

I have a Procunier "CNC" tapping head. The difference is this one has no overload clutch, and depends on the CNC to control plunge depth.
I do a LOT of blind holes, and the spiral FLUTE taps are incredible! These bring the chip up the flutes and out the hole.
There are also thread forming taps, that make no chip. You need to start with a larger hole, and these are for softer materials only.
It is just WILD to tap a bunch of holes at 300 -600 RPM, just zoom in, zoom out, and on to the next hole.
Jon
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tap
reversal
tap,
using a

toolbox
taps.
My first choice in tapping heads is the Procunier, too. Great devices regardless of the machine on which they are used. To my knowledge, none of their tapping heads have torque limiting devices. Get ham handed and you're likely to bust taps. They're certainly capable, although they have a very nice feel if your quill isn't tight. I've had outstanding luck with them. I've used spiral fluted taps, but I still prefer the gun tap for general use, especially when tapping tougher material. I've had a few failures with them, unlike the gun types.
Harold
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Aribert writes:

Oh, you want advice AND to gloat in the same thread? Puh-leeze.
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You probably know this, but Ettco is still in business, http://www.ettco.com / and they still make tapping heads.
You might contact them. They sent me a parts diagram for my 1930's model
-- Greg

...
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All the tap heads I have rebuilt by Procunier and Ettco use a cork lined double cone clutch and a set of planetary gears inside. The tap is driven into the work by one side of the cone clutch until the body of the tapper is stopped by a physical limiter on the drill press or other machine. The tap loses driving friction at this point by the cone clutch disengaging, and goes into a "neutral", which limits tapping depth. You can pause tapping at this point if you desire, by keeping the head floating in this neutral zone, with your feed handle. Whenever downward pressure is released, the other face of the cone clutch, along with the planetary gears come into play, reversing the taps rotation to back out of the hole. The gearing speeds up this process of getting out of the hole more quickly. Once the tap clears the work, it automatically switches directions via a coil spring against the cone clutch to once again drive in a right hand direction. The screws you see around the lower end of the tapping head are the spindles of the planetary gears. Take the top off. It won't explode. Parts are not cheap. I just spent over $400 converting a Procunier from Morse taper mounting over for use on a Burgmaster 2BH with a threaded spindle.
RJ
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Backlash wrote:

And store them in an upright position to keep oil from getting on the clutch.
michael
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I checked a Procunier tapping head today, and found that it backs the tap out of the work at 2X the speed that it feeds into the work, for those interested.
RJ
--
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YOU came."
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Greg, Backlash, others: Thanks for the wealth of info - now I know a bit on how to use it and how it works. I hope to be able to play with it this week end. Since this is a small unit, the tap head chuck only opens up to 0.25 inch, I need to rumage thru my misc tap bucket for a spare or two that I don't mind sacrificing - it seems that I have many more duplicate taps that are greater than 0.25 than smaller.
And no, I will admit that I did not even think of looking to see if ETTCO was still in business, I just assumed that most companies have either gone under or have been consolodated / renamed in the past 80 years. In looking in a couple of catalogs to see if I could visually identify "gun" taps, I came across current ETTCO tapping heads.

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