Sweeping a DTI held in the spindle is consistently accurate plus you don't need to purchase a coax indicator but new toys are always good!
But they are not rigid tapping on a Bridgeport so a little slippage doesn't matter and might even be good to reduce tap breakage. Any slippage is fatal when rigid pecking.
Not only are cheap ER holders more accurate than most drill chucks you get more Z-clearance which often matters when drilling tall pieces.
Sweeping a DTI held in the spindle is consistently accurate plus you don't need to purchase a coax indicator but new toys are always good!
I agree. I was getting frustrated using a normal indicator. Decided I could put a coaxial indicator to good use. Take time and dial them in tight. Should only have to set center for each holder 1 time per holder adjusting nut and setting x. Then I can pop in any tool and set z offset. Besides I have no less then a dozen ways to indicate why not add one more. I like new strategies to limit frustration and get it done.
Going to need a mt2 er 20 collet holder or some other.
I sent a link earlier (https://www.amazon.com/Collet-Holder.../dp/B08CRM1PK8) for an ER20/MT2 that is supposed to be in stock.
thanks for link!
I guess amazon was being stupid when I searched. I did same search and 4 others popped up that are in stock!
Amazon filters people to certain buyers and hides others. Then your link unlocked the filter and now I see those other vendors.
By the way coaxial indicator was well worth the money. took all of a minute to indicate center. The front view and slide dial markers help big time .
FWIW, I was highly advised that even though the MX does rigid tap, to hold the tap in a T/C holder anyway for a little extra safety factor.
Thanks for heads up
I was shopping for that option also. I could find a 5c collet holder in bxa size but no oxa size tool holders. then a 3/4 5c collet to hold tts tc unit and your on your way!
This would have a huge tool overhang from tool post out to end of tc unit. Not optimal imho
Anyway I have the mt2 taper ordered for rigid tapping on 8l lathe. My concern at this point is I have no way to measure rpms. I would like to check spindle speeds before i start testing .
this would eliminate one factor. Then its down to settings.
Isn't the actual spindle RPM irrelevant with rigid tapping? The infeed/outfeed should be controlled by the spindle rotation.
Within the usual speed/feed limits of course. I've not done rigid tapping on the SL15, but have done lots of external and internal threads which should be very similar code-wise. You put in a short air-cut in front of the part to get everything synced-up properly.
My guess is it starts moving the axis at the 'book' rate, then modifies feed based on spindle encoder inputs, so you need enough encoder pulses for it to settle down. IIRC there's a tooltip in the conversational threading screen for that lead-in sync distance that suggests how long to make it.
Last edited by shred; 03-18-2021 at 10:38 AM.
I did, but then I mounted an encoder The encoder delivers the exact RPMs and this value is (at least on my modified mill) displayed on the DRO. You can consider the encoder derived RPM value to be "exact".
As Ken mentions the feed tracks the spindle speed (on a non servo system) so the exact spindle speed is not particularly important.
On these non servo systems the spindle speed is harder to control so it's allowed to run and the Z axis motion is synchronized with the spindle encoder. At the required depth the spindle decelerates and reverses while the Z continues to track the rotation.
If I had a lathe I'd certainly be rigid tapping.
I can imagine on a large mill/lathe a little travel in the tool holder might be advantageous because there will be very little flex in the system. On at least my 1100 it works fine with a rigid ER20 holder.
Step
Kstrauss , turbo step,
Your right
it does thread any pitch perfectly at all speeds with a single form tool. It would need to be in sync to do that.
I'm Always going back to what I learned on mill setup. New tech works different
Step, I believe that you have added rigid tapping to your 1100. Any chance for a few details of what is involved?
I was being to fussy about the process. Rigid tapping using sprutcam turns out to be simple.
I also spent time to dial in the tools accurately only to find the tool post is not that good and repeatability lacks.
still it works fine as is. If more accuracy is required I will need to develop other methods for axial tool holding of drills.
I believe I did
Originally using a parallel port and later through the mesa card. There are a few issues if you want to avoid a custom Bit file and I wouldn't recommend my solution to anyone else. For milling I only thread mill so I haven't tried it for quite some time. I did notice that the RPM DRO no longer showed the speed when controlling the spindle via the potentiometer so I'll have to look into it some time. Things did change when Tormach introduced the encoders on the MX series so I expect I need to adapt somehow.
I'll let you know if I make any progress but I'm afraid it's not high on my priority list.
Step
May ask you regarding G84 (Rigit Tapping).
Before our Kuraki Fanuc 15M loss the parameter the tapping G84 could run smoothly but after loss the paramater (we dont have backup, ask the CNC service to do Restoring), our machine cannot perform G84. When we execute for tapping G84, the spindle could go in but cannot out after reach the positiion Z. Please help me any paramater may be change. Thanks for your kindness.
This forum is for the discussion of Tormach machines. You are more likely to get a useful answer by posting in a more appropriate place.