3951
General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course
« on: October 06, 2012, 07:03:56 PM »
Surface FINISH also comes into play. The drawbar force IS important to maintain force on the taper it is NOT like a morse #2 where the taper is so long it has a lot of holding power from the force exerted on the taper by the pin(tool holder). Remove the tension from the BT30 holder and it WILL fall out under cutting loads. Let it get light and it will chatter the toolholder in the spindle under heavy loads
I do not KNOW of a STANDARD value or calculation to estimate the force needed. Each Manf I have dealt with has their OWN NUMBER working range they want you to set the drawbar tension to. They know the basic values needed then add in a fudge factor from in field experinces over the years.
Most are similar for each taper. THICKER spindle shafts may need more, harder spindle shafts may need more.
Call a spindle grinder or repair shop and you will get the genaric values used by most OR they tell you to call the manf for the correct values for the machine.
The standard taper used for all the sizes is not used by accident it it a compromise of torque transfer AND being able to release it from the spindle
Just a thought, (;-) TP
I do not KNOW of a STANDARD value or calculation to estimate the force needed. Each Manf I have dealt with has their OWN NUMBER working range they want you to set the drawbar tension to. They know the basic values needed then add in a fudge factor from in field experinces over the years.
Most are similar for each taper. THICKER spindle shafts may need more, harder spindle shafts may need more.
Call a spindle grinder or repair shop and you will get the genaric values used by most OR they tell you to call the manf for the correct values for the machine.
The standard taper used for all the sizes is not used by accident it it a compromise of torque transfer AND being able to release it from the spindle
Just a thought, (;-) TP