First off a discussion of the pros and cons of TTS to give a background to the subject of R8 TTS vs BT30.


  1. Great educational video and as always you seem to use facts to dispel the thinking of how superior BT30 is over TTS especially for those of us that rarely use cutters over 3/8”.
    I was planning on getting the 1100 MX because it now has 10,000 rpm spindle and a luxurious X-Y compared to my 440.
    But I had never considered not being able to use My ITTP. I can’t go back so I REALLY need one with a BT30 holder. My uneducated feel is that a dedicated BT30 holder will be more accurate than an adapter from the current TTS to BT30. I’m very interested in hearing more, And a BT30 ITTP is essential.
    Thanks Cliff..

  2. Excellent discussion Cliff! I think the TTS system would be much better it the shanks were back tapered about 0,1 to 0.2mm over the collet grip length and the collet had the matching back Taper. That would greatly increase the pullout strength as it would be self tightening. The shanks would need a gentle taper on the length past the collet grip area to ease the temporary over expansion of the collet as you insert the tool and having 4 to 6 collet slots would help also. Also moving to a 7/8″ collet size would increase available thru capacity.
    ATB, Robin

  3. Pull studs and drive dogs are another advantage of the bt30 over the tts. Running the 770 with atc on the tts is a nightmare and more trouble than it is worth to constantly readjust to prevent crashes, busted forks and broken cutter$ (One week is the longest the atc has gone without crashing on me). I would think the bt30 would alleviate some of those issues with the included tapper over the straight shank tts.

  4. Many great points mentioned in this Cliff. This sort of pulls your question off into another direction but I can only comment about what I’m experienced with. Given that a true centered position to the spindle center line would be very important with a touch probe then I’ll use my Haimer 3D as an example. They recommend a dedicated holder is used. On mine I use a 3/4″ R8 end mill holder that gets indexed each time in the spindle using that ridiculous internal set screw in the slot on the R8. So the Haimer unit was zeroed in that holder to my spindles C/L. It’s a good accurate and repeatable system as I’m sure you already know. I honestly can’t see any good reason why your Touch Probe would be any different for it’s initial set up and daily use. Like the Haimer it pretty much requires some type of dedicated holder that fits what ever spindle taper the machine has. Even the best machine and collet system is always going to have at least some measurable runout. Using a dedicated holder and zeroing the probe in it will remove some of the variables if the best results are expected. Marking the spindle and tool holder with an index position might even be a good idea for non R8 spindles or one’s where the index set screw has been removed.

    Interesting and well explained points about the comparisons between the R8 and BT 30. I’d just always assumed a BT 30 would have a much larger advantage over an R8 than there apparently is. And good information about the importance of keeping high use threads well lubricated. I learned a long time ago and luckily on an easily replaceable part that dry threads start wearing quickly. Those wear particles then start quickly accelerating further wear. My unscientific gut feeling is there’s as much as 50-1 life span between clean well lubricated threads and unlubricated. Plus as you pointed out most of the available torque is actually going into holding the tool with much less being wasted due to friction. Your demonstration of how vibration / chatter can cause tool pull out was eye opening and a very good lesson.

  5. Excellent video! Cliff very good explanation

  6. Thanks Cliff, very interesting. Now I can stop wondering if the TTS system is better for the manufacturer than the user. What I took from this video is that it is a reasonable system if I keep to smaller tools and try to avoid hammering with flycutters and facemills etc.

  7. Interesting Cliff. As stated below, Pull studs and drive dogs are a key difference and may hinder your ideas on a bt 30 collet idea when a tool changer is taken into account. BT30 ‘Plus’ standard adds spindle face contact like the TTS which is definitely a better idea and probably what Tormach should consider. FYI I use a BT30 holder on a VMC drill tap machine and use a 3/4 collet to hold a Haimer with a TTS shank. I imagine the easiest fix for your probe is to buy BT30 blank holders and bore to accept your current 3/4 design.

  8. Interesting discussion Cliff. My next mill will definitely have a 30 taper and for all the reasons you mentioned, having a probe with the same taper should increase accuracy, so I’d go for that. Having a BT30 to TTS adapter collet could be a money saver if I don’t sell all the TTS tooling so that could also be useful for smaller diameter tools.

  9. I am looking to get a tormach with the bt30 and would like to own one of your probes. So I don’t have feed back per say but am looking forward to seeing how you go about the change.