DavesWimshurst
DavesWimshurst
- Joined
- Dec 7, 2008
- Messages
- 102
- Reaction score
- 3
Robert,
By testing on drill bit did you mean drill rod? Anyway you should first try testing on the outside of the tailstock barrel. With the barrel fully extended and both the tailstock locked and the barrel locked I get much less than a thou error in the full exposed length of the barrel. The usual allowed error is very slightly high at the nose end of the barrel (the actual test is done on a precision test bar inserted in the Morse taper but I don't have one). Have you checked for embedded chips under the tailstock and between surfaces that allow set over for tapers? Your problem may be just a chuck mounted on a crooked or bent arbor, does the error direction change if you reinsert the chuck rotated about it"s axis by 180 degrees? Perhaps a picture of your test set up would help us.
Dave
By testing on drill bit did you mean drill rod? Anyway you should first try testing on the outside of the tailstock barrel. With the barrel fully extended and both the tailstock locked and the barrel locked I get much less than a thou error in the full exposed length of the barrel. The usual allowed error is very slightly high at the nose end of the barrel (the actual test is done on a precision test bar inserted in the Morse taper but I don't have one). Have you checked for embedded chips under the tailstock and between surfaces that allow set over for tapers? Your problem may be just a chuck mounted on a crooked or bent arbor, does the error direction change if you reinsert the chuck rotated about it"s axis by 180 degrees? Perhaps a picture of your test set up would help us.
Dave