I admit I don't do a lot of tapping holes, but my interest in a tapping head is to offset tendonitis I have contracted in both wrists as I get older. Even after switching to spiral flute taps when I first saw one, which I consider a super great invention as they are so much easier to turn, I still have some trouble muscling through sizes like a 1/2-13 hole in thick steel plate ( 1/2" or thicker) and pay for it the next day. It's the same reason I just added power feed on the Y axis of my X2 clone mini mill. Sparing the wrists, because I really enjoy this hobby.
After the fiasco with the Grizzly Tapping Attachment, which is being returned, I spent some time looking at tapping head use videos on YouTube. Not a single one of the many I viewed showed the clattering, clutch slipping mess I had experienced. With a quality tapping head it is a lovely ballet of machine operation to watch. One video had a series of holes to tap on a CNC mill, and it ran through them like butter, smoothly and quietly, by comparison.
So hopefully this story is at a close. I have bought a TapMatic Model 50 TC-DC from a seller on eBay who happens to be less than an hour away from here. It looks to be in very good condition by the photo, and he said they only used it a couple times in some small batch runs in his factory that makes conveyor equipment for the movement and handling of mail marketing material. It has a 33JT taper on its drive end, so I will be able to put it right on my drill press spindle in place of my chuck, when I want to use it.
This was educational. Especially when I turned to eBay to look for a tapping head that for sure had a 33JT input. Most of the eBay listings don't say what taper is on the drive end. But it appears the later runs of the older TapMatic models started stamping the input taper right on the front of the tool. So sometimes the picture would tell what it had, even if the listing did not. I visited TapMatic's current website, as well as finding copies online of manuals for their older models they don't make anymore. All of them were available with different tapers, using the varying model numbers to tell what was MT2, 33JT, different threaded options, etc. Unfortunately, they do not seem to put the actual model numbers that would tell you that on the face of the tool so you could see it in a photo.
Thanks to everyone for the help and suggestions! And I hope this information will be useful someday to anyone else who has designs on removing the MT2 taper from a Grizzly Tapping Attachment, saving them the hassle of trying to do so.
If anyone who happens to have one of the Grizzly models finds it to work well without chattering and spitting out the tap, I'd love to learn what is inside the clutch pack, just to satisfy my own curiosity. I really think something was missing or defective inside the one I tried.
Also, for general information, I had emailed TapMatic and asked if the top parts into which the various styles of arbor are mounted could be interchanged if one bought the necessary bits. His reply: "the heads are unique and can not be changed by swapping out parts." So when shopping for one it is necessary to get the kind that has the taper you need.