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Tapping Q's....

Janger

(John)
Administrator
Vendor
I'm learning about roll taps or form taps. Instead of cutting the threads they press the thread into the metal. Kind of like how bolt threads are rolled but not with hot material. I bought a few to try and thought before I broke these tools I would at least do some research and watch some people using them. So I found a video to watch but there is a weird point where he is using some sort of floating tap head with a regular cutting tap. The tap seems to be bouncing all over until it engages in the hole. ie it's not running true to the hole axis. See time frame 8:03 to 8:20 before and after the tap engages.


I thought that was really strange. ? Is that how those floating heads work? they float in XY as well as Z?

and again at 12:00...

How do you clamp 20 separate parts really well all at once without any of them being loose? Brilliant idea from Edge Precision in the comments. Lot of work but if you are making thousands...
Edge Precision​
4 years ago​
John. If you really want to go first class with you fixture (You probably wont). On your moving jaw drill and ream or bore a hole at each parts location so you can install a small piston with a o-ring seal. Drill a cross hole to intersect all the pistons holes with small pipe plugs at each end. Start each piston in each hole than fill full of oil (try to eliminate as much air as possible ). Mount the jaw and clamp all the parts than crack one of the plugs to bleed off some air (like bleeding breaks). The hydraulic pressure will balance the force on all the parts even if they very in length. The only down side to this is you have to have a full fixture or blank parts in every station.​
 
Last edited:

PeterT

Ultra Member
Premium Member
CNC is above my pay grade. Regular tapping heads on manual machines typically uses rubberized collets.
http://www.tapmatic.com/product_line_catalog_rubber_flex_collets.ydev
The tap is locked on the flats like normal, but the net effect of the metal collet vanes & rubber pie segments is to provide some radial float so the hole/tap axis can be off by a little bit. The axial float you typically see is internal to the head, not the collet AFAIK. That works in conjunction with the clutch torque control as the tap advances in & then self-reverses when being retracted (while the spindle is stiill running forward).

This has some CNC & regular tapping videos & info.
http://www.tapmatic.com/videos.ydev?video_id=11
http://www.tapmatic.com/product_line.ydev

I've never done rolled taps but I think they require different hole size & torque presets for tapping heads. How that's accomplished on (non tapping head) direct driven CNC's I haven't a clue.
 

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