View Full Version : Need Advise on Threading Head
01-15-2007, 11:22 PM
I need to buy a threading head for a drill press. It has a MT4 spindle taper. After reading the descriptions in a couple of catalogs, I find that I have some questions. At first glance, it appears that the Tapmatic line is a good choice. But I am open to suggestions. I have never seen one up close, much less operated it so my first question is how it is set up and operated.
Does the operator have to hold the arm that prevents it from rotating, or is this usually secured to the column or something? Or does it just ride against it? I have seen the model that attaches to a Bridgeport spindle, but I doubt that my spindle is that same size so that model is probably out.
My next question is about the down feed. Obviously, the tap will move down as the thread is cut. But how is this accomplished? Does the head itself provide a sliding fit? Or does the operator have to feed it down with the drill press's feed? Or what?
Finally, I see models that use individual sized collets and others that use the rubber collets that handle a range of sizes. Is there any reason to go for or avoid either of these? The rubber collets are obviously more economical. But do they work well?
Anything else I should know?
Your Old Dog
01-16-2007, 06:09 AM
I'm rooting for you to get an answer on this one!
01-16-2007, 06:38 AM
Although we have a couple of those Tapmatic units at work I always just chuck the tap either in a chuck or in tap holders we have that go right into the taper. The tap holders are something like a collet and are supposed to alow the tap to slip if it jams. Supposed to but not always!
Down feed the tap pulls down on the spindle to feed. Make sure you do NOT have power down feed engaged on the drill press or you will get funny threads or broken taps.
01-16-2007, 08:06 AM
I don't think any of the commonly available tapping heads are any better than another, but I would prefer the Tapmatic because it is more compact than the others, and the torque is more easily adjusted.
They work by maintaining a light down pressure on the quill feed handle, the tap will pull the head down. When tapping depth is reached, raising the handle will reverse the feed direction and retract the tap. tapping speed is from around 500 RPM to 2000 RPM. Retraction is usually at about twice the tapping speed. This is the basic sequence, there are some differences in the different styles and manufacturers.
Be aware that there are tapping heads for CNC equipment that have the slip clutch and other features of the reversing heads, and are about the same physical size, but do not have the reversing function, counting on the machine cycle to reverse and retract. These cannot be used on the drill press.
The reaction arm stops the head from rotating, and must be restrained to keep it from swinging. It is usually allowed to ride the drill press column, and often a light chain is attached to keep it from swinging around and catching the operator's chin when reversing. I would not recommend holding it by hand.
The collets in the chuck serve to keep the tap on center, the tap is restrained by a double nut affair that grips the driving flats. The rubberflex collet will handle a larger range than the steel collets, and is probably more economical. The steel collets are not too difficult for the HSM to make if they are missing.
Tapping heads are usually rated by capacity in brass, cast iron and mild steel, and by the size range of taps they will physically accept. While it may be possible to install a larger tap in a small head, it might not have a strong enough clutch to handle it.
Most of the Tapmatic heads use Jacobs Taper mounts, and if a MT#4 is not installed, they can be changed. Some of the others use proprietary threaded mounts, and they must be fabricated or purchased if they need to be changed. Many of the used Tapmatics I see have had the JT pinned, so I suspect they are prone to slipping in the larger sizes.
01-16-2007, 12:20 PM
I have a tapping head. I like it but I would suggest that you do get a "brand name". Mine is a "Big Accu" or something...made by Sowa and sold in Canada. I'm still trying to buy parts for mine. The previous owner (Fleabay purchase) let the unit slip out of the taper a few times and the nose got broken up a bit.
They do work awful slick though. I needed to tap 30 holes in aluminum. It went really quick and made me a believer.
01-16-2007, 01:47 PM
FWIW, I thought this thread had decend tapping head information:
01-16-2007, 03:06 PM
I have a Tapmatic 30X and love it picked it up used . The the tapmatic web site is an excelent source for tapping info you can dowload manuals for the products and also download lots of other tech info on tapping. The lever that stick out rides against a bar mounted on the table or machine head. the tap feeds itself the operator follows by feeding the quil. A quick lifting of the handle reversesthe tap and the tap comes out. WWW.tapmatic.com
01-16-2007, 10:15 PM
Thanks to all for the response. I think my questions are answered, at least for the present. Sounds like the Tapmatic X series is what I want.
Thanks to all.