A Quick Tail Stock Alignment Trick

[rake60]

Did you ever think just how sensitive your finger tips are?
You can feel .002 of an inch. Can you feel the edge of a piece of paper
laying flat on a table? Paper is .002" thick. Can you feel a single hair?
That is also .002"

Anyway on to the post.

Mr. Frank Ford has a quick and easy way of aligning a tail stock on
his web pages based on the plain old feel.
It's at Tailstock Alignment Trick
Now if you will be turning a 20" long bearing fit next, this procedure may
not get you close enough, but if you will be boring a 1" long cylinder bore
I'm willing to bet it WILL be.

Before this is shot down, I DO know the proper way of aligning a tail stock.
The fact is is doesn't have to be that critical for making the small scale
parts that most of us are turning.

Check out the Back to Machining Index at the bottom
of that page. He has some very good information on there!!!

Rick

 

[wareagle]

I am missing something on this technique. Maybe I am too tired to think straight, but I don't see that you would have a difference in the two discs by using this method. It looks like a quick way of aligning the tail stock, but I am just not comprehending exactly how it works once the disc is parted off.

Hmmm.... I sense a sleepless night coming on :lol:

 

[Lew Hartswick]

I am missing something on this technique. Maybe I am too tired to think straight, but I don't see that you would have a difference in the two discs by using this method. It looks like a quick way of aligning the tail stock, but I am just not comprehending exactly how it works once the disc is parted off.

Thats the whole point. The discs are identical and when held together by the
center you can feel even a .001 difference in the alignment. It would also
be a good test to see if the tailstock were at the right height, wear etc.
...lew...

 

[shred]

I think the trick is the nearly-aligned tailstock and center drill will make a conical hole that's centered but bigger than the center drill (aka using the center drill as a conical boring-bar), Swap the center drill for a center and it will align on the cone a little deeper, but centered.

 

[wareagle]

Don't I feel like the dummy! Well, not really. But after I thought about it some, I can see how it works very easily.

Neat trick, no doubt!

 

[Hexbasher]

ahem......(i just got back from a 11er shift at the shop)*sign

thats not accurate

yes, that method can get you to within a few thou taper per foot....

yes, both the head stock and tail stock are aligned...

BUT, cutting pressure is a big part of tapers, regardless if the head stock is aligned with the TS or not ...head stock alignment with the ways is a big deal too .....cutting pressure is gonna want to push that TS back, out or compress the metal contacting with the center, distort your centre drill mark, push on the bearings of your live center (obvious if its old and worn its crap), push on the backlash of the adjusting screws on the TS, the cutting acting tents to "climb" on the tool and pull the TS up...

etc etc etc etc etc....you see eh?

thats why lathe standards are junk (unless you want to get close)

heavy drilling always throws TS out of whack , so for me, each time i need to turn something long with a close tol., i dial in the TS after roughing.....luckily, 80% of my work i do is bearing or bearing related.

downer,. you have to machine that little spacer thing each and every time you want to use that method


my quick, fast, easy method to get that TS close fast without machining anything
-dead center in TS
-dead center in spinal (or chuck something and turn something sharp and pointy)
-push TS towards head stock
-pinch a piece of MS in between the two centers(Al isn't a bad idea as long as its milled) use something soft so you don't knacker up your centers' tips
-adjust until the pinched piece of metal is 90 degrees to the ways(use the one squinted eye and thumb technique if you wish

 

[rake60]

Yes tattooed_machinist there are many much better ways to align
a tailstock. This was just suggested as a quick and easy alternative
when a dead nuts result is not required.

When I need a perfectly straight taper free cut at home I set mine by
turning a long section of what ever metal I will be turning, mic the
taper and adjust the tail stock to remove the taper. You can get it perfect!
Two days later the temperature in the shop may be 10 degrees different and
the minuet expansion or contraction of the machine and or the bench can
have it tapering again.

The machine I run for a paycheck is completely CNC. No chance of human
error, the machine is going to do what the program tells it to. Yet from a
cold start it will taper. No big deal for a CNC. If it's tapering .002 over 20"
you just adjust the program to tell it you WANT a .002 taper in the
opposite direction and it will cut dead nuts straight. As the machine and
temperature in the shop warm up that taper may disappear or even go
past that point to taper in the opposite direction. The you adjust the
program again to keep it within tolerance.
When we're doing it for a living it has to be perfect every time.
If there's a machine broken down in the middle of nowhere and the repair
parts that are shipped there to fix it don't fit, heads roll.
The shop I work for has total accountability for all the parts we manufacture.
Every fit you finish, you record the result on an IPI (In Process Inspection)
report. Recording a false or fraudulent entry on one of those forms can
lead to serious legal repercussions.

At home we don't need to deal with those pressures.
If it fits and works, it's GOOD! :wink:

Rick