How do you measure the center point of the head stock?

[jdervin]

I've become suspicious that the head and tail of my indexer are not aligned. In the past, I've always set zero based on the live point in the tail stock. Now I want to confirm that the center of the head stock is perfectly aligned with the tail, but can't think of a good way to chuck up something accurate enough to trust.

Given the chuck provided by ShopBot with their indexer, I'm wondering how others go about ensuring that it is perfectly aligned with the tail.

(For the record: I only have the #2 and #3 jaws, so there is a limit to how small an object I can use)

[myxpykalix]

Hey John,
When i set mine up i did alot of other things like running a string line and other stuff but the quickest way to make sure the headstock and tailstock are lined up with each other is to simply take the lathe chuck off the shaft of the indexer motor and you'll see a dimple in the center of the shaft.

move your tailstock up and see if the tailstock center goes into the center of the dimple in the end of the indexer shaft as in the pic.

When i mounted a 2x6 wood base for mine the first thing i did after bolting it in my gulley i ran a reference line in it with a .25 bit.

I lined up my aluminum tracks to that line as I knew that line corresponded with a straight line from the router.

I also made a simple jig to measure center. I just took a bit lowered it to the center of the dimple and zeroed it. Then i just cut the 2x6 to that height so when i want to quickly find center i just Zzero to the surface of the jig.

[myxpykalix]

more pics of my setup

[jdervin]

Thanks for the tip, Jack (no pun intended). Looks like I've found my problem (see the photos -- and note that for this comparison, I mounted both the head and tail on the same piece of aluminum track, so the only variation is in the head and tail and not the mount).

I'm assuming that the simple fix is to loosen the mounting screws and line everything up. Let me know if there are any tricks or hurdles to consider.

Also, I'm hoping to come up with a precise way to quickly chuck up a center point so I can test for alignment right before cutting (without having to take the chuck off each time). Any ideas?

[myxpykalix]

Also, I'm hoping to come up with a precise way to quickly chuck up a center point so I can test for alignment right before cutting (without having to take the chuck off each time). Any ideas?

Yes, go back to my post and look at the piece of wood in the pictures. That is cut to the height of the center point on my shaft. So now when i want to find center of any size, shape stock I pull the jig out (fancy name for piece of wood) and simply do a C2 to the top of the wood and you are now zeroed to the center of the shaft.

Some guys have a plate on their indexer and then do a offset to find center on the stock. My thought is, what if something goes wrong with those settings?
This way it is set each and every time to the center. But to each his own..

I mounted both the head and tail on the same piece of aluminum track, so the only variation is in the head and tail and not the mount).

I'm assuming that the simple fix is to loosen the mounting screws and line everything up. Let me know if there are any tricks or hurdles to consider.

mounting it on the same piece of aluminum won't give you an accurate representation of your problem. I would get myself a laser and shoot it down the center of your indexer shaft and then even if you mount the tailstock 8 feet down your table you ought to be able to line up the tailstock and the tip of the dead center to the center of the shaft on the indexer.
I don't recall if i had that much play in the groove that the indexer and tailstock rode in.

Also get yourself a 90 or 120 degree vbit and line that vbit to the center of the shaft on the indexer(my pic shows an endmill). Once you have that lined up run it straight down your table to the tailstock. That can be your failsafe guide.

[Brady Watson]

John,
That's one issue with mounting the indexer on the table side extrusions. My advice would be to shim the headstock where top 'lip' that overhangs the AL t-track - so that it remains in alignment when you slide the tailstock back & forth. The tailstock will move more than the headstock in daily use, and seems to sit fairly true even when mounted on it's side. Let gravity put the tailstock where it 'wants to be' and then align the headstock to it, using shims where necessary, since the HS has a lot more slop in it as it relates to the t-track than the TS does.

Now...in terms of checking alignment you can do a few things...I know it is a bear to feel confident about the centers being aligned when you have them 30" apart The first method consists of chucking a 60 or 90 deg v-bit into the spindle and then align it to your live center point. Get it dead on Z zero and the centerline of the rotary axis, using the v-bit and the live center as an indicator. Then move along the axis without moving in Z up to your drive center. A nice pointy steb center or pointed drive center will work fine. Observe if it is still dead on center or if there is a deviation. You can also just chuck up another v-bit in your chuck if it runs true.

Another way, and less accurate depending on the casing itself, is a laser pointer. If you can chuck it up and shoot it at the tailstock, you can observe the 'point spread' of the laser and how it gets broken apart by a nice sharp live center point. It will get you pretty close, but it is not 100%. Rotate the chuck with the laser on and see if it get's 'wally' as it turns around.

Then there is the 'test bar' method, which involves machining a round piece of stock and measuring the diameter at each end to see if there is a difference. If you know how to 'read' the bar, you can tell where it is running out of true.

Start with the shims and the better of your 2 eyeballs to get it in the ballpark and go from there...The stock SB setup has quite a bit of 'allowance' to let the HS & TS slide down the t-track. If you want to kick it up a notch, drill & tap the blue motor mount on the top & bottom edges where it overhangs the AL t-track. Then install 4 screws that will let you adjust the HS in your Z direction & then lock it in. You can also adjust pitch/yaw/twist of the HS with this arrangement. If you've ever seen a decent metal lathe, it has side to side adjustment screws on the tailstock to fix the issue you are having right now...but you won't see many lathes running 90 degrees like yours.

-B

[propellers]

John,

What visual means of alignment used will not result in perfect alignment. I use a method for XY but could be used for Z also. I had been plagued with visual misalignment for years since coming close to giving up on a CIA contract the light bulb of idea came on. We are carving to a thickness of .02 of the rear edge of propellers and this procedure has made alignment fast and perfect.

This procedure will be reference only and you can adapt your own ideas for the specific application. You will be measuring the tailstock live center flat area, or even the holding chuck for the live center.

Whatever location used, determine the diameter and turn a part that is the exact diameter and chuck into in the headstock.

In the router chuck use a drill blank or even a length of steel rod, we use .5", any diameter will work as long as it does not bend.

Use a wire that has an alligator clip on each end, attach one end to the Z zero plate and the other on the headstock. Touch a wire or metal object to the zero plate and the rod chucked into the router. Check to see if the input light illuminates on the monitor that is used for the, C2 keystroke, Z zero switch routine. If the light illuminates you have proper connection.

Open Keyboard command, K. Move Z axis so the rod in the router is below center on the part chucked in the router. Move the Y axis towards the part in the chuck. When the router rod gets close to the chucked part be sure to select the Fixed Move Button so your movements are very small.
When the router rod touches the part in the chuck, zero Y, ZY command. Move the alligator clip to the tailstock.

Move X so the router is at the tailstock, do not move Y axis, keep at zero. On the flat side of the live center or whatever point chosen for alignment, adjust the tailstock hold down so the light illuminates on the monitor. Your tailstock is now in perfect alignment in Y axis.

For Z Axis..Move X axis back to headstock and connect the alligator clip to the headstock. Move the router rod, Y axis, to the opposite side of the part in the headstock. Move Y axis now towards the part in the headstock until the rod in the router touches the part in the chuck, which is determined by the input light illuminating on the monitor. Write down the value of the Y axis. Divide this number by two which represents the center of the headstock or what is the Y zero position. Move Z above the chucked part and to the new Y center, zero Y, ZY command. Now do a C2 command which will zero the Z axis and move Z axis to .5”.

Move X axis to the tailstock and connect the alligator clip to the tailstock. Make sure the router rod is above the tailstock measuring point. Using keyboard command to move Z axis towards the measuring point and when getting close to the measuring point use the Fixed Move Button to arrive at Z Zero. If you reach the measuring point and you do not see the Input light then you will need to raise the tailstock, if you see the light before reaching Z zero then the tailstock must be lowered.

I would like a program that would have fill in’s for this routine but, not smart enough. As I become older and the vision is getting worse this has been a tremendous aid for alignment. Hope it works for you.

[jdervin]

Okay, so I've tried a combination of the above suggestions and think I have the head and tail very well aligned. That is, until I put the chuck back on. Then I'm getting less than satisfactory results. How are you mounting V-bits, lasers, turned blanks, etc. in the chuck in such a way that you can know that they are perfectly centered and that they are exactly parallel to the center of rotation? Everything I've tried is clearly inaccurate at best.

FYI: the chuck on my headstock is a Oneway "Talon" with the #2 jaws, which have a 1-5/8" minimum capacity. I also have a set of #3 jaws, but nothing smaller than the #2's.

[Brady Watson]

How are you mounting V-bits, lasers, turned blanks, etc. in the chuck in such a way that you can know that they are perfectly centered and that they are exactly parallel to the center of rotation?

A dial indicator. It's the ONLY way to KNOW for sure.

-B

[jdervin]

I've got one of these dual guage spindle squares, but still can't think of a precise way to hold it in the chuck of the head stock.