Another Tailstock Alignment Method

[firbikrhd1]

Over the years there have been many discussions on tailstock alignment and many methods mentioned to accomplish the task. Here is yet another I saw recently. No doubt others have already seen this, but when I did I thought it was a good idea, particularly for those of us with old machines since the tailstock can be aligned anywhere along the ways to account for wear at any distance from the headstock. Other methods do the same job but alignment is limited to the length of the test bar or a specific distance from the headstock.
Take a look at this video:

http://www.youtube.com/watch?v=fEysFBjGkyE&list=UUKLIIdKEpjAnn8E76KP7sQg&index=7

Any thoughts, positive or negative, from the professional machinists here?

[Barrington]

Not a professional... so probably missing something, but if he's happy to do it that way, why does he need two parts ?

Just put a single one in the spindle, zero dial guage, move it and the dial guage to tailstock, adjust.

???

Cheers

.

[Jaakko Fagerlund]

Didn't watch the whole video, but I would just dial the bore of the tailstock with a DTI held in the chuck. And with a tailstock the most important thing is to have it laterally in the center and that the tailstock quill is parallel to the spindle axis.

If the tailstock sits a little higher or lower, it doesn't matter that much as the vertical dimension.

[JCHannum]

It is an interesting method. I wish he would edit his videos more, this could have been done in about three minutes. It does have some advantages over other methods, especially when the tailstock is located a distance from the headstock.

[Forrest Addy]

This is a good trick you can take to the bank. It ' an accurate method and is low in cost to implement. It eliminates the long shafts, turning tests and other monkeying around. It has the convenience of variable tailstock location to suit the length of the intended part - very useful on a worn lathe. I've seen it used for many years off and on. Tubal didn't invent it nor does he so claim; he presents it as though he was simply passing on a good tip. Humble and capable guy, Tubal.

I can see why Tubal runs long. All his videos are tediously slow to my way of thinking. However, he's an experienced teacher used to pitching his content to suit the slowest noob. I use the same technique myself. What can be passed on with a few words to a bright experienced peer might take 20 minutes and a couple sketches for a low experienced noob unused to the concepts and vocabulary. No slam intended. Different people have different learning curves.

Also you may have noticed, early in the video, Tubal addressed using one shank swapping it from spindle to tailstock but that complicates the repeat zero verification. Two shanks really are handier than one givien the price per unit.

BTW, according to common industrial usage, they are Morse to Jacobs "shanks" not "arbors". An arbor is a shank designed to retain an item of rotary tooling with a nut.

I would prefer a spindle end shank long anough to be used with a chuck in place. I'd probably face off the end of the as-received shank and silver braze an extension on it before turning back the taper.

[wagnerite]

a little OT: I think Tubal is doing a great service explaining machining concepts. His videos are more than "tips and tricks," and the extra information he includes is always relevant. I think he follows these forums, I hope he sees that there are folks that really appreciates his videos.

[darryl]

I see he's using an adapter to be able to machine the #2 taper in the #3 spindle bore. How does he or we know that the adapter perfectly centers the shank? If it doesn't, then there will be error. We don't know that the spindle taper is precisely centered either. The process should really contain all this information.

If you start by indicating the spindle bore at a couple different depths, then you verify this condition first. Another way to do this is to machine the stub just like he did, but then indicate the turned part a few times. Move the shank around in the bore a couple of times and re-check. If the indicator shows the same every time, then you know the spindle bore is good.

This is the basic method of checking the #2 taper shank as well. To do the multiple tests, you would remove and turn the shank, but keep the adapter in the same rotational position. If the indicator shows no movement with a few different rotations of the part, then you have proven the adapter to be concentric. Then when you do the tailstock alignment, you're actually aligning the tailstock bore and not just the turned surface on the shank.

Of course the other part of this is that the bore should be aligned in all the ways- front to back, height, and parallelism. It would help in this if the stub left on the #2 taper shank was longer- then you could see more of the possible misalignment issues.

[bob ward]

This is one of those 'duh why didn't I think of that' moments.

Brilliant, its cheap and simple and as has been said it can be easily used to check the tailstock alignment for any location and quill extension of the TS. And thinking about it, the 2 diameters don't need to be exactly the same just so long as you know what the half difference is.

How does this compare with RDM? Just kidding.

[Tony Ennis]

I'm unaware that Tubal (AKA Lyle) visits. But I enjoy his videos. They're great for beginners. He's a frustrated shop teacher. I find it amusing that he has more, and more interested, students now than he ever did when he was teaching.

[mygrizzly1022]

I'm unaware that Tubal (AKA Lyle) visits. But I enjoy his videos. They're great for beginners. He's a frustrated shop teacher. I find it amusing that he has more, and more interested, students now than he ever did when he was teaching.

Hi

I agree, i seldom miss class and somtimes I sit through class multiple times

Bert

[Forestgnome]

It looks like it's also a good way to know if your tapers are repeatable. Pop it in and out and recheck. I'm thinking mine might not be. I'm going to have to try this though. I usually do it on the fly by measuring the end diameters, then moving the tailstock over half the distance using an indicator on the tailstock end.

[dian]

"This is a good trick you can take to the bank. It ' an accurate method and is low in cost to implement. It eliminates the long shafts, turning tests and other monkeying around."

well, i would call this monkeying, how should that be acurate? and whats the problem with turning a bar and see how it is? after all, thats what you need to know.

[doctor demo]

BTW, according to common industrial usage, they are Morse to Jacobs "shanks" not "arbors". An arbor is a shank designed to retain an item of rotary tooling with a nut. .

Well, I guess Morse or Jacobs had a bad day the day they made mine. It says "Arbor" right on the side.

Steve