Hi all, I am (like many others) patiently awaiting my PwnCNC spindle/VFD and dustboot package to arrive. I am a hobbyist and I have been using a standard SO3 since October 2020. I have modified the belt tensioning system with a straight path design of belt tensioner by Neil Ferreri. I tune the belts by vibration to C3 at 440 cycles. This gives me a belt tone at 130.813Hz. The ideal tension of the belts can fall anywhere in the range 100 ~ 150Hz. I have purchased the fixture plate, stiffener rails and modular vices from Saunders Machine Works in Ohio.
I have prepared my SO3 to receive the PwnCNC air cooled 2.2kw spindle package by exchanging my Z plus Z axis for the much heavier duty HDZ Z axis with ball screw. I added the 80mm HD spindle mount. While checking squareness of the rails, I changed all of the system wide delrin V wheels for new ones and replaced all of the Gates GT2 belts. The picture shows my machine ready to go once my spindle arrives.
Questions for users:
What type of collet nut is provided with the spindle?
Has anyone used a bearing collet nut with their spindle?
Does anyone have any information on the torque setting for the collet nuts?
Thanks Chris. I realised that the nut was an ER20 collet nut and wondered if there is any collective experience at PwnCNC of ER collet nuts with included ball bearings? I may have misunderstood but I got the impression that a bearing nut reduces the friction and wear on the collet and permits higher torque values. I found this link to REGO-FIX (inventors of the ER collet system) and I guess their guidance must be accurate.
Thank you for your helpful response, Chris. I will post my own experiences just as soon as I get my hands on my very own PwnCNC spindle/VFD package delivery.
I use a torque wrench when calculating how to take the uncertainty out of a regular requirement to tighten any fastening. The issue I have had in the past is when reefing hard on a tool to apply torque, the point when sufficient torque has been applied is hard to know.
My Saunders Machine Works fixture plate, with its sea of 840 x M6 holes in the ½" thick aluminium baseboard, had the potential to leave me with damaged bolt holes in the case of applying variable torque to the M6 bolts while using the modular vices for workpiece holding.
I had originally set a torque wrench to 5 N-m. This value is the point when the baseboard just held the vices very firmly. That setting proved to be good enough and in more than two years, not a single threaded hole is showing any signs of wear damage through over tightening. I am hoping to replicate that sort of comfort and certainty when clamping ER20 collets on my much anticipated PwnCNC spindle.
