Tailstock Upgrade

[JPG]

First of all, this has been the standard way of boring a centered hole using a lathe for a few hundred years.
I did not know they turned wood pens a few hundred years ago.

Secondly, the wood is well supported. I'm using a proper chuck with tall jaws that extend well over half the length of the blank. (Not that it is needed considering we are talking about a short, fairly thick chunk of wood with no lateral pressure being applied.)
OK! Not sure I agree a pen/blank is a 'fairly thick chunk of wood'.


Wrong. If the blank isn't centered, then you just get a off-center hole. In fact, it is not an unusual technique to intentionally offset the work piece to move the location of a hole.
IF the drill bit were turning instead of the piece chucked, it would merely be off center. However since the chucked piece is turning, an off center positioning of the piece WILL cause an oversize hole.

You will, however, get a larger hole if the bit isn't centered against the center of the chuck. Hence my original complaint about the tailstock.
This is the same as the preceding paragraph. If the centers (piece in chuck or bit in tailstock) are not aligned, how can one say which one is 'off center' and that one or the other gives a different result. Either way the misalignment will cause the same result.


Using any other lathe, this is both the fastest and the most accurate way.
Usually. Doubt boring pens/blanks would work an a LARGE lathe.

I'm actually to the point now where I just ask my brother to use his mini-lathe to drill the blanks for me. It takes him only a minute or two to do a whole batch and he doesn't even have to mess with trying to line-up the drill.
Only because he has no way to do so. ALSO a 'mini lathe' is designed to work with 'mini stock'.
This isn't rocket science, this is all covered in day 1 of any high school shop class that has lathes.
In a brief overview(of many other things as well), I doubt pen/blank boring is discussed on day 1.

Jonathan

YES! The tailstock has 'flex'. Yes it can be 'loose'. Yes it can be deflected(maybe). Yes a mounted drill bit can be 'off center' AND off line(not parallel to the axis of rotation).

I doubt the original designers of the SS had pen turning in mind during conception time. That being said, the spt tube tail stock with its rotatable morse taper socket does NOT provide us with a good solid way to mount a drill bit for boring pens/blanks using a headstock mounted chuck.

It IS however quite adequate to its originaly designed purpose.

[JPG]

. . .

(I fail to understand why pen turners drill holes before turning. Seems to me with a little longer stock they could leave some wood in the chuck and also some on the tailstock end. The only reason I can remember is "pen blanks" are expensive and come in this size. Seems a larger block of wood and a bit more waste would be easier.)
. . .

It is a whole lot easier to get the inserts through the blank and mounting them onto a pen turning mandrel if the blanks have a hole bored through them!:D

[charlese]

Thanks to the answer to my "hole first" question. That helps!

Now another suggestion for Johnathan. I don't know what type of chuck you are using on the power side, but I assume a drill bit chuck on the tail side. Since you are using a brad point bit, can you align the wood to the brad point, using slight quill pressure then adjust the chuck on the power side while the drill bit point is into the center on the tail side? --Then, after the drive chuck is tightened, move the quill, so the bit is a little into the wood. Then turn a couple of rotations by hand to get it started. It procedure will put pressure on the tailstock that should remain through the drilling activity. This proceedure is what I use (on larger stock) and has served me to be a sure fired way to get the bit started in the center to avoid a funnel shaped hole.

Paper shims, as suggested earlier, might help also. I'm sorry, as I have a hard time understanding the tailstock flex issue, as mine just won't flex! With the collars firmly on the base and the 'sleeve and insert assembly' firmly tightened, there is no measurable flexing.

This thread would be an excellent one for explanatory photos. Do you have the capability to snap a picture of your setup?

[charlese]

Here is an example of horizontal boring in the lathe mode. This was boring a 1 1/16th inch hole through a 15 inch long pepper mill base.

After finishing the boring, I messed with the tailstock. Previous posts are absolutely correct. The stop rings must be placed in the right place and the tightening bar must apply pressure to each post of the tailstock.

This boring probably would have gone easier, if I had a 1 1/16th in. spade bit. But in this case a forstner did the trick with two 6 inch extenders. needed frequent backing to relieve shavings/dust.
[ATTACH]3905[/ATTACH]

[ATTACH]3906[/ATTACH]

[JPG]

Now scale that down(stock and bit) and keep the tailstock 'slop' constant. You can appreciate the frustration pen borers are experiencing.

[charlese]

My point was - there is no - or should be no tailstock slop!

If I can bore through 15 inches and come out in the center on the other end, I should be able to bore a straight hole through 5 or 6 inches with a relatively shorter drill bit shank.

Maybe the problem is the ability or inability to chuck up a piece that measures only 1/2" X 1/2" and align it to the tail point. Or maybe it is a problem in aligning the center of the quill with the center of the tail piece.

[a1gutterman]

Funny thing. With this conversation in mind, I re-watched the Rick Davis DVD that I have. His tailstock sure looked rock solid, even when he was banging on the center he had in it with a mallet. I have never turned a pen blank, so I am certainly no expert, but the thing that he (Rick) did to insure that the mount locks created equal pressure onto the accessory tubes and the tailstock tubes seems like an likely place to look for "slop". As we should all know, and what he demonstrated, was that if there is knot equal pressure on both tubes, one will move.

Equalize the bolts in the mount lock to ensure that it will tighten equally to both tubes.

[JPG]

. . .

Equalize the bolts in the mount lock to ensure that it will tighten equally to both tubes.

. . .

For procedure, see #8 below
https://forum.shopsmith.com/viewtopic.php?t=3297

[charlese]

..., but the thing that he (Rick) did to insure that the mount locks created equal pressure onto the accessory tubes and the tailstock tubes seems like an likely place to look for "slop". As we should all know, and what he demonstrated, was that if there is knot equal pressure on both tubes, one will move.

Equalize the bolts in the mount lock to ensure that it will tighten equally to both tubes.

You bet,Tim! That's the right approach. Also, what I found when messing with the tailstock is - if only one of the two stop collars gets loose and moves just a mite (guessing a 32nd") up or down, the center points will no longer be true. To add to this - If one of the stop collars is not firmly seated onto the bench assembly some wiggle of the tailstock can occur, - even if the locks are evenly tightened.

However, after the collars are properly adjusted, they will stay so for years and when the tailstock is fully seated and locked, no play or wiggle will occur. If it does, the bench tubes or the way tubes are loose, or the bench assembly is cracked.

I have assumed that the eccentric mounting tubes are tight and the tailstock insert is also firmly set.

[JPG]

. . .

I have assumed that the eccentric mounting tubes are tight and the tailstock insert is also firmly set. . . .

Your tailstock tubes are 'eccentric'?