View Full Version : Floating Tap Holder.

23-01-2018, 05:52 PM
I have been trying to find a floating tap holder using ER collects and R8 shank. No luck.

All I can find are ISO or MT shanks.

How do these work? How does the tap (or reamer) float?

Could I just make one?


23-01-2018, 06:50 PM
I am not sure exactly what you want to do, but ArcEuro sell a set of sliding tap and die holders.


Then you would need to machine an R8 soft end to 16mm to hold it. This is a lathe accessory though and I can't imagine it being used in a milling machine quill.

23-01-2018, 07:36 PM
I'm sure you could make a floating tap holder, it just needs to be spring loaded up and down so it floats in a central position but allows free movement for Z synch error on a mill without rigid tapping capability, then add a way to hold a tap.
Splines or a cross-pin can be used to provide drive whilst allowing vertical float.

23-01-2018, 07:37 PM
If your mill doesn't support rigid tapping is Thread Milling an option for you?

24-01-2018, 07:37 AM
These pcm collets hold taps and are sprung loaded, they are available in the whole range of er sizes.

You can buy them from wnt but they are quite pricey, I found a few er25 on ebay that I use on my Denford triac. If you buy the largest diameter you can find you can make sleeves to hold smaller taps.


24-01-2018, 07:54 AM
Cutwel also sell them if this is suitable for you...


24-01-2018, 11:54 AM
Thanks James but have you seen the price!! Over 100 per tap size. There are tapping collets available (Standard ER collects with a squarenhole at end to fit specific taps) at about a quarter of the price. Trouble is the collet holders are not available in R8. Question still is how do springs allow the tap (held rigidly by the collet) to float in the holder.

They have to be able to float in all 3 axes but still apply torque to the tap?

How are these floating holder designed?

24-01-2018, 11:58 AM
@magicniner: I am only tapping up to say M10 so no need to thread mill

24-01-2018, 12:02 PM
They have to be able to float in all 3 axes but still apply torque to the tap?

No they don't.
Floating tap holders assume the machinist/CAD/CAM Monkey is competent enough to align X and Y and only float in Z, this is to prevent breakage when a machine's Z feed doesn't perfectly match the required movement for the tap to maintain neutral tension.
Floating reamer holder requirements differ

24-01-2018, 12:07 PM
@magicniner: I am only tapping up to say M10 so no need to thread mill

I Thread Mill down to M3, some things I make require a full thread right down to a shoulder, this has internal and external full threads to shoulders.


Internal and large external are both 1mm pitch and so were cut with one thread mill, if you are only tapping bolt holes milling may be overkill but it also allows you to produce any class of thread with one tool, unlike taps. ;-)

24-01-2018, 02:37 PM
Ah so! Thanks for clearing this up.

So I will bore out a blank R8 to fit a parrallel shank ER20 holder. Fit a drive pin and spring to bias the holder at 50% of the slot. Then use the square ER20 tapping collets.

Seems like a plan

24-01-2018, 08:23 PM
Sounds like a plan!
Ensure your materials are hard enough and well lubricated enough to avoid galling, making the pin square with soft corners and using a Moly lube on the sliding areas will help,

12-04-2018, 07:44 AM
Floating tap holders, aka Tension/Compression Tap Holders are the perfect solution when you need to tap a hole. Bridging the synchronization gap between toolhodler and Z-axis feed, the spring mechanism compensates for the minute acceleration.

Factory Automation (http://www.jawee-automation.com)