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Alignment or miss

Joined
Aug 26, 2006
Messages
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Location
Hampton Roads Virginia
John, love the installments on your Planet Mesquite turning. I bet the problem solving is just as much fun as the turning. So as not to hijack you thread I wanted to ask about the bore sighter as an alignment tool. Looking on the net, I found three possibilities of shaft misalignment, radial, axial and angular. We know that just because the drive center point lines up with the live center point does not mean the lathe drive shaft is in alignment with the tail stock quill. Spinning the bore sight in the lathes morse taper, inscribes a small circle on the wall. The question is, is the center of that circle aligned with the drive shaft? My bore sight has the little adapter rings so as to get a tight fit in the morse taper, I can push/move the sight a bit to get a bigger circle, smaller circle or just a dot, the center of the circles and the dot are all in the same place. I know I don't need the accuracy, it's more a curiosity thing...
 
Joined
Apr 11, 2014
Messages
424
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420
Location
Dallas, TX
My gizmo works - ain't pretty, but it works.
I found two kinds of bore sights - the end of barrel and the cartridge - I selected the cartridge thinking it best to use the length of the spindle. Plan is to simulate the rifle chamber on a faceplate.
Step-1 / Pic-1:
  • Bought a bore sight cartridge from local sporting goods store. Selected the Remington 25-250 because it was on close-out at $15. Any cartridge will do - the longer 30-06 might have a slight advantage.
  • On a 4" faceplate I attached a 18mm Baltic birch piece and turned it round.
  • Put the calipers on the neck of the shell - came to 1/4" - drilled a 1/4" hole all the way through - the cartridge was a great friction-fit
Step-2 / Pic-2:
  • Bought a floor-plate for 3/4" pipe and a short nipple.
  • Drilled 4-holes at 90-degrees in the nipple and tapped to 1/4-28
  • Mounted the floor plate to the baltic birch - inserted the nipple - inserted four bolts as adjusters - pressed the bore sight laser into the assemble
  • Put it on the inboard end of the lathe and turned it on with the little screw in back
  • Moved the cartridge until I could see a red dot on the far wall - screwed in the adjusters
  • Rotated the spindle - the circle was about 8"-diameter
  • With the adjusters, I was able to get the dot stationary in about 3-minutes.
  • Because the 1/4" hole is in the absolute center and the red dot is stationary, my thinking is it's spot-on
  • Remounted the gizmo on the outboard end and put the tail-stock / live center on the bed
  • Attached a drilled board with grid paper on the live center - turned the laser on - WA-LAH - dead nuts on the point
Step-3 / Pic-3:
  • Remounted the gizmo on the inboard end
  • Attached a piece of grid paper to a standing board and set on the end of the extension
  • Re-centered the dot and marked
  • Moved the board in toward the spindle - it is critical that the board be in the same east-west position on the bed
  • The red dot moved up about 3/16" - east-west it didn't move. The bed is lower towards the head-stock - now the work begins
Next step is getting the two beds (lathe bed and the extension bed that sits on top of the sub-bed) parallel.
Cartridge Laser.JPG

Align Oneway.JPG

Truing Laser on Extension.JPG
 

john lucas

AAW Forum Expert
Joined
Apr 26, 2004
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Location
Cookeville, TN
I was thinking on my powermatic of mounting any a laser on the outboard end since that end is 3/8". I couldn't use my bore sight but might be able to rig up the small laser I use on my hollowing rig. If I put a 3/8" morse taper collet in the headstock and then aligned the laser so it was center on both ends that would pretty much tell me where the headstock is pointing.
 
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