Fingers crossed it'll cut ally

[Ross77]

I'm just looking at spindle design and A/c bearings so I'm intrigued if you know of a cheap type.

im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them

Do you mean rigid enough for milling Ali? If so be careful adding addition preload to a factory set tandem one as I believe you just end up un loading one side!!! if its a double row then lock it to the sharp end and fit a floating bearing at the other end.

According to SKF the distance between the CL of the bearings should be 3 to 3.5 time the shaft dia, so 12mm shaft = 36 to 42mm so a 100mm shaft should be way long enough.

The optimum design seems to be to use 2 opposing A/C bearings with a spring loaded pre-tensioner.

Have you seen the "DIY spindle design" on here, or these?
http://www.cnczone.com/forums/showth...t=12184&page=6
http://www.cncathome.com/spindles.html

It seems this has been done many times and the problems are mounting the motor to the spindle, the first link post no. 64 and 65 shows a flexible mount and water cooling for the motor.

I also have an ER11 collet and a RC motor to power it but as its for machine No. 2 I haven't got around to doing anything with it yet. so I will be watching with interest.

Good luck

[blackburn mark]

I'm just looking at spindle design and A/c bearings so I'm intrigued if you know of a cheap type.

"5200 zz z 2z ball bearing 10mm A/C" ebay aprox £16 for two... they might be to good to be true

just end up un loading one side!!!

och!! i hadnt thought of that... i hadnt decided if id just throw two in for good measure or pre-load them against each other
iv decided now!! cheers ross

According to SKF the distance between the CL of the bearings should be 3 to 3.5 time the shaft dia, so 12mm shaft = 36 to 42mm so a 100mm shaft should be way long enough.

i think you misunderstand, jonathan has a motor that has a 100mm long body so with a 100mm shaft there is no room left to add an A/C bearing and housing


yea iv seen those thread, they make interesing reading, one of those guys has his own ballancing machine!! to posh for me:)