Lurk
Cast Iron
- Joined
- Feb 10, 2014
- Location
- Peak District UK
Time for another head scratchier
I am setting up a plan for bedding the lathe headstock to the newly scraped lathe bed. In order to ensure the head stock is in-line with the bed ways for spindle alignment I have to be able to take some meaningful measures against a test bar in the spindle (well I think thats the plan). However, the headstock bearings in which the spindle runs are white metal and initial assessment showed 0.035" of lift at the chuck when the bearings halves were clamped down (obviously excessive wear and no shims between the halves). I am trying to avoid re-pouring babit or machining new bearings.
My query is as follows -
From what I have read to date, the vertical lift at the chuck should show something of the order of 0.002" for a 3" dia' bearing journal - by the same token, other specifications suggest a tolerance of between 0.001" & 0.002"/inch of diameter - i.e. between 0.003 and ).005" between journal and bearing ID - which is going to give far more lift surely ?
Then I get to the dimensions given by Dr Schlesinger for tool room lathes - up to 0.0004"/12" - on a test bar. I do not understand how that can be achieved with a bearing described above - stationary you would get one result - once running the shaft would align within the bearing oil and give you another figure surely.
Any thoughts or suggestions much appreciated ?
Thanks in advance
Mat
I am setting up a plan for bedding the lathe headstock to the newly scraped lathe bed. In order to ensure the head stock is in-line with the bed ways for spindle alignment I have to be able to take some meaningful measures against a test bar in the spindle (well I think thats the plan). However, the headstock bearings in which the spindle runs are white metal and initial assessment showed 0.035" of lift at the chuck when the bearings halves were clamped down (obviously excessive wear and no shims between the halves). I am trying to avoid re-pouring babit or machining new bearings.
My query is as follows -
From what I have read to date, the vertical lift at the chuck should show something of the order of 0.002" for a 3" dia' bearing journal - by the same token, other specifications suggest a tolerance of between 0.001" & 0.002"/inch of diameter - i.e. between 0.003 and ).005" between journal and bearing ID - which is going to give far more lift surely ?
Then I get to the dimensions given by Dr Schlesinger for tool room lathes - up to 0.0004"/12" - on a test bar. I do not understand how that can be achieved with a bearing described above - stationary you would get one result - once running the shaft would align within the bearing oil and give you another figure surely.
Any thoughts or suggestions much appreciated ?
Thanks in advance
Mat