jskeen
Member
I've suspected that there is something gone afoul with my lathe for a while now, but never really spent too much time thinking about it till tonight, when in the midst of replying to another thread about Out of Round blanks, I had to stop and spend a solid hour lying in a dark, silent room trying to get my 3 year old daughter back to sleep. So here's my Idea, please help me disprove, improve, or remove it as you are able.
As we all know, if the tips of the dead and live centers on your lathe don't touch when you move the tailstock all the way up, it can make your pens end up out of round. But, if they do happen to touch perfectly tip to tip, that doesn't guarantee that you won't still have problems for two reasons. The first is that just because the tips touch with the tailstock all the way up is no guarantee that they still would with it down in it's usual spot for turning. The second is that even if the tips do touch perfectly, there is no way to tell or adjust how the actual centerline of the bores align all the way down the axis of rotation.
I found a couple of places that sell these little widgits:
http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=lathes-acc-mrstool
and
http://sierramold.com/WMorse_Taper.htm
for $18 And $24 respectively, but i'm not really sure even that will really fix the problem totally. I guess they would help you accurately shim your headstock so that the bores are concentric at one point on the ways, and that may be enough to eliminate most of the OOR issues when TBC, but you still have to question if the tailstock is moving that bore out of alignment somewhere down the ways.
SO..... Here's my thought. I know this is not going to be accurate down to the last whillionth of a skillimeter, but it may give some indication as to what's going on with your lathe without having to lay out a big chunk of cash. If you were to take a piece of 3/8 or about drill stock, or even just cold rolled from the borg about 18 to 24 inches long, and check it to see if it's bent by rolling it on your tablesaw or jointer bed, and chuck it in your mt jacobs chuck in the headstock, so that it extends through the bore of the tailstock chuck it seems that it would give you a fairly accurate gauge as to how centered the axis of rotation in the headstock is to the centerbore of the tailstock AS YOU MOVE IT down the ways. I know, I know, intrinsic runout in jacobs chucks and linear deviation in a steel rod that length, ect. ect. ect. but would it be accurate enough to let you know if something is out of whack enough to be causing a 2 inch or less pen blank to turn out of round for some reason?
What say the cognoscenti among us?
As we all know, if the tips of the dead and live centers on your lathe don't touch when you move the tailstock all the way up, it can make your pens end up out of round. But, if they do happen to touch perfectly tip to tip, that doesn't guarantee that you won't still have problems for two reasons. The first is that just because the tips touch with the tailstock all the way up is no guarantee that they still would with it down in it's usual spot for turning. The second is that even if the tips do touch perfectly, there is no way to tell or adjust how the actual centerline of the bores align all the way down the axis of rotation.
I found a couple of places that sell these little widgits:
http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=lathes-acc-mrstool
and
http://sierramold.com/WMorse_Taper.htm
for $18 And $24 respectively, but i'm not really sure even that will really fix the problem totally. I guess they would help you accurately shim your headstock so that the bores are concentric at one point on the ways, and that may be enough to eliminate most of the OOR issues when TBC, but you still have to question if the tailstock is moving that bore out of alignment somewhere down the ways.
SO..... Here's my thought. I know this is not going to be accurate down to the last whillionth of a skillimeter, but it may give some indication as to what's going on with your lathe without having to lay out a big chunk of cash. If you were to take a piece of 3/8 or about drill stock, or even just cold rolled from the borg about 18 to 24 inches long, and check it to see if it's bent by rolling it on your tablesaw or jointer bed, and chuck it in your mt jacobs chuck in the headstock, so that it extends through the bore of the tailstock chuck it seems that it would give you a fairly accurate gauge as to how centered the axis of rotation in the headstock is to the centerbore of the tailstock AS YOU MOVE IT down the ways. I know, I know, intrinsic runout in jacobs chucks and linear deviation in a steel rod that length, ect. ect. ect. but would it be accurate enough to let you know if something is out of whack enough to be causing a 2 inch or less pen blank to turn out of round for some reason?
What say the cognoscenti among us?