arrow 500 spindle bearing renewal

[boslab]

Anyone help with a problem, ive had on of these given to me to fix, the bearings are gone, you can feel it bumping round when you spin it, some fitters have been tinkering, they have removed the drawbar unit and belt, taken the clamp slotted nut off the spindle by the pully, i can now look down on the pully and sey the keyway, also just behind the head is a 4x3 plate bolted down with m6 bolts into which 2 airlines are fitted into elbows, removal reveals 2 chambers which appear to be ported into the spindle, is this air mist lube? if it is its ni wonder the spindle failed as the chambers are dry, or is this some sort of lock or airbearing or somthing.
any help would be appreciated
thanks
mark

[greg b]

Hi the lines your talking about are for your tool clamping and release,and theres a smaller line for your spindel lubricator which pushes air and oil at the same time.The air continually runs through this line all the time at low pressure and every 15mins or so the lubricator on the back of the machine squirts a shot of oil into the line to lube the spindel bearing the air takes the oil to the spindel in a mist and also purges any swarf while machining.I just found my splitter block that ajust the air and oil feed at the back of the machine has a pair of filters in it and they were corroded closed,Im thinking they may have been some sort of iron type filter.But cutting to your question Im thinking your lubricator is not working properly or those little filters are blocked if the bearings are dry,keeping in mind the lubrication is only a mist not a flowing stream or theres a chance your bearings could skate and wear out prematurely which was pointed out by Rob Varney a knowledgable technician.regards Greg.