Please help an idiot

[TRS]

Okay, first let me say that I'm not only new to pipemaking, but woodwork in general. I've completed two pipes, both of which were squared on a miter saw. I then marked the center of the top of the block and used a square to trace the center line all the way around to the shank face side. I used a circle template to lay out the outer and inner diameters of both the bowl top and shank face on the center line and marked the centers of both. My first pipe was drilled on a press, the second on my lathe. A third stummel was also laid out this way and drilled on the lathe; it was the most perfect drilling I've done to date. (I later f*cked up the shank royally on the sander, but that's another story...) Now the past three pipes I've tried this way won't work; I chuck them in the lathe, center either a forstner's point or a drill bit on the shank's centerpoint where I want to drill, and then as I spin the chuck by hand to adjust, the center point goes off (as it comes around to the opposite side) by a good margin (1/8" or so). I've made sure the face of the block in the chuck is square and is flush against the chuck..... wtf? I can't figure it out, because I'm inexperienced with these tools, and also probably an idiot. Help please anyone, if'n ye can. Thanks again!

[KurtHuhn]

Is it possible that the tailstock or headstock is off-center? Or that the chucked is buggered? Either of these would do exactly as you've described. I doubt the squaring of the block makes a difference - I don't square any of my blocks prior to drilling them, and everything comes out perfectly centered every time.

If you have a morse taper in the headstock, put a jacob's chuck with a small (like 1/16") in the headstock, and a live center in the tailstock. If the tip of the drill bit meets the tip of the live center, spin by hand, and see if the tip of the drill bit stays centered on the live center. If not, the spindle could be warped. If it isn't centered to begin with, you will need to adjust either the headstock or tailstock to bring them back in line with each other.

[TimGeorge]

Just a wild guess but I am also new to the lathe, and at least with the Jet Mini I discovered that you cannot crank the tailstock with your drill chuck all the way back as far as it will go. The taper fits properly and stays square to the headstock only if it is out about an inch. Kind of hard to describe, and probably not your issue at all, but what the heck maybe someone will benefit ...

[T3pipes]

If your chuck is self centering, close it all the way down and make sure they all hit center at the same time. If you put them in in the wrong order they will be off. Yes, this is something i learned the hard way .

[TRS]

If you have a morse taper in the headstock, put a jacob's chuck with a small (like 1/16") in the headstock, and a live center in the tailstock. If the tip of the drill bit meets the tip of the live center, spin by hand, and see if the tip of the drill bit stays centered on the live center. If not, the spindle could be warped. If it isn't centered to begin with, you will need to adjust either the headstock or tailstock to bring them back in line with each other.

Ugh, this seems to be it. The 1/16" starts out centered on the live center's point, but half a revolution around it strays a tiny bit towards me.... exactly like the block was doing. Thanks again for your help Kurt. Is this, erm, fatal to the lathe......?

Edit; something just occurred to me as I was grating cheese: this is an old Craftsman lathe from the 1930's-40's. Is it possible this is an issue with the bearings? or do they not wear in that fashion?

[KurtHuhn]

Ugh, this seems to be it. The 1/16" starts out centered on the live center's point, but half a revolution around it strays a tiny bit towards me.... exactly like the block was doing. Thanks again for your help Kurt. Is this, erm, fatal to the lathe......?

Edit; something just occurred to me as I was grating cheese: this is an old Craftsman lathe from the 1930's-40's. Is it possible this is an issue with the bearings? or do they not wear in that fashion?

Oh, that just sucks. It might not be fatal, but it might be out of commission for a while. Which model lathe? You may be able to find a replacement spindle for it.

The bearings, if they went, would likely allow pretty free lateral movement of the spindle. Grab it by the threads where the chuck screws on and shake it, if it moves, the bearings should be replaced. However, it would be unusual for worn bearings to make the spindle act as you described. The movement would typically be fairly random, and attempt to follow the highest angle of momentum - the heavier side of an imbalanced block. Moved slowly, it would constantly point low (following gravity), but at higher RPMS, it would want to follow the block.

[sethile]

Ugh, this seems to be it. The 1/16" starts out centered on the live center's point, but half a revolution around it strays a tiny bit towards me.... exactly like the block was doing. Thanks again for your help Kurt. Is this, erm, fatal to the lathe......?

Edit; something just occurred to me as I was grating cheese: this is an old Craftsman lathe from the 1930's-40's. Is it possible this is an issue with the bearings? or do they not wear in that fashion?

Early in my pipe making exploits I went to a friend's shop (an instrument maker) to try making a pipe on his old 6" Atlas lathe, (closely related to Craftsman). I could not get the bit to stay centered when I rotated the block in the chuck. After looking it over for a while I decided it could not possibly be anything I did and asked my friend to come check it out. It turns out the tail stock was completely out of alignment with the headstock. We lined it back up and it was fine. Check out that tail stock and see if something has changed, or can be adjusted. It must be something simple like that or maybe something moved since you mentioned drilling with perfect alignment before. I don't think anything would have worn out that quickly....

[TRS]

Check out that tail stock and see if something has changed, or can be adjusted. It must be something simple like that or maybe something moved since you mentioned drilling with perfect alignment before. I don't think anything would have worn out that quickly....

I'm going to do this as soon as possible. The same thing occurred to me earlier in the day and then it slipped my mind. I remember having a problem lining things up with it after I first got it, so I kinda forgot about it and went back to the drill press. Then when I tried the lathe again a few weeks later is when I had the successful blocks. Also, I tried searching the internet for a 3/4X16 1MT spindle and that situation looks pretty bleak.....

I can't thank you guys enough for your help.

[TRS]

Well, I ventured out in the blizzard that's dumping on us to the unheated shop. (This didn't help my mood any) I found the little threaded pins on the tailstock that align it and adjusted them with the jacob's chuck in the head and the live center in the tail until it was centered. Nothing. Same problem. I also removed the spindle and held it against a square and it didn't seem bent at all, though I'm not sure this is the most accurate way to gauge this. The spindle did not slide out very easily, and required a couple light taps with a rubber mallet.....

I think when I've thawed out I'll go back out when I'm gonna shovel again and just chuck up some scrap and drill it, just to observe the results and see if it accomplishes anything. I dunno....

[FredS]

What type of chuck do you have?

3 jaw or 4 jaw?

Is it a universal/scroll chuck where all the jaws move when you turn the key? Or is it an independant chuck where each jaw moves only when it's individual leadscrew is turned?

How does the chuck attach to the spindle?

[TRS]

Independent 4 jaw, screws right on to the spindle..... I've tried using both 3 and 2 jaws on it.... (block won't fit with all 4 on)

[FredS]

Based on that info, and your original post, it sounds to me like you simply don't have the block centered in the chuck.

EDIT: Suppose your tailstock was 1/4" off center towards the far side. If you aligned the centermark on your stummel with the tailstock, then spun the chuck 180 degrees, your mark would now be 1/2" away from the tailstock (towards you). So, even though the marks lines up with the tailstock, they are not in the center of the headstock spindle - which is what matters since that's what your stummel is attached to.

[TRS]

Thanks Fred. I had assumed that if I had a squared block placed flush against the chuck, and then zeroed in the point of a bit on the point where the center lines met, all I'd have to do would be tighten the block in the chuck at that spot. When it went out of center I only tried to adjust it up and down along the chuck. After reading your post I went out and adjusted it by also pulling and tilting the block away form the chuck and it centered much better. Thanks again to everyone for putting up with me and helping my slow brain. I hope you can't get kicked off this forum for incompetence....