CNC Lathe Tailstock - Alignment and Checks

Before proceeding with the checks and adjustments outlined in this post ... we highly recommend you review and perform the adjustments contained in our previous post :
CNC Lathe Headstock - Alignment and Checks

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Continuing our series detailing alignment checks and adjustments that may be required after a visit to Crashville ... this post deals a little with the other end of your CNC lathe ... the tailstock.

The tailstock may end up getting a bump in variety of ways and for a variety of reasons ... sometimes it doesn't even have to be involved in the cutting !! Sometimes just sitting somewhere on the bed ... it can be bumped or hit with the turret body. These kinds of "crashes" will inevitably cause the tailstock spindle to fall out of alignment with the main spindle ... the result? ... taper when cutting a workpiece that is held in the chuck and supported by the tailstock.

However ... if you perform any main spindle alignments as outlined in the post above ... you definitely will need to re-check the tailstock alignment. Shifting and adjusting the main spindle will surely result in a mis-alignment with the tailstock.

Alignment Check
The easiest way to check the alignment of the tailstock is to test cut on a piece of material the length of which you feel is appropriate ... with one held in the chuck and the other end supported with the tailstock. The stock should have a precise center drill hole to accept the tailstock center. Obviously the longer the piece of stock used for cutting will result in the closer the alignment adjustment ... so you should select a diameter and length of stock that is appropriate ... you're a machinist ... you know what will work best.

Make sure to take enough stock to insure the bar OD has been "cleaned" ... then take a light finish cut the appropriate length and measure both ends. The difference in diameters at the headstock and tailstock end will tell you the amount of mis-alignment.

Alignment Adjustment
If you reviewed our headstock blog post ... you are already familiar with the type of construction used on most tailstock assemblies ... which is similar to the construction used on the headstock assemblies. As the pic below illustrates ... the tailstock body is usually bolted to the tailstock base. There are usually "push-pull" bolts similar to the headstock assembly that can be used to push-pull the body on the base for alignment.

One way to make the adjustment ... and should be the starting procedure ... is to mount an indicator on the chuck face ... move the tailstock all the way up to the chuck so you can sweep the tailstock spindle with that indicator mounted on the chuck ... and adjust the tailstock body until you get a zero reading. This is a fairly good place to start ... but you should still conduct the test-bar procedure below to insure that the whole tailstock body is "square" with the spindle. Performing only this tramming procedure will not insure that the tailstock body is out of square ... and may still result in a taper when the tailstock is employed in shaft cutting.

1. Mount an indicator somewhere on the tailstock base against the tailstock body to measure the amount of movement you will employ in the steps below.
2. Crack the hold down bolts loose.
3. Use the push-pull bolts to adjust the body in the direction and by the amount you deem appropriate.
4. Make sure the hold down bolts are fairly snug.
5. Take another test cut.
6. Measure again the headstock and tailstock diameters ... repeat steps above as necessary.

The above may take a few tries to get it right ... but the indicator mounted is Step 1 will help you evaluate your movement direction and amount of movement to help you hone it in. It really is a trial and error type of procedure.

As mentioned above ... whether it is a visit to Crashville involving the tailstock ... or a re-alignment of the headstock ... the above re-alignment of the taistock is just as critical to accurate machining as any other check and adjustment. We hope that the clues and tips here can help you get back on track with accurate machining with your CNC lathe.

Until Next Time ... Happy Chip Making !!

Please Visit our Website for More Info on all our Real World Machine Shop Software

Product Introduction : Vise Jaws and Cut-Off / Grooving Tooling

Every once in a while we like to include some new product information that we come across while surfing the web. Products that would interest us based on our chipmaking or machine repair experiences. We are not endorsing any product ... we don't have any relationships with the companies ... just passing the information along. We know everyone out there are adults ... and can make up your own minds if the products we bring to your attention are a good fit for you and your requirements.

This is such a post ....

Product #1 : Walter Grooving System
Anyone involved with CNC turning ... specifically grooving and cut-off ... knows that oftentimes those operations can be tough. Eliminating long stringy chips ... or just eliminating plain old chips ... can be a real challenge. We stumbled upon the Walter CUT - SX system of grooving tools and knew right away we wouldn't be the only ones that were impressed. Sure the turning grooving / cut-off tools are cool ... but they also have system for milling cutters as well.

From the Walter website :
"The Walter CUT-SX system offers a variety of advantages :

• Lower inventory cost due to one-cutting insert type being used for multiple tool variants
• Maximum tool life due to the optimized self-clamping system
• User friendly self-clamping system for fast replacement of the cutting edge"

You can watch an in-depth video using the YouTube link below

http://youtu.be/jeqJDHGVJZM

Product #2 : Carvesmart Vise Jaws

Anyone working an HMC or VMC knows the tough road of changing vise jaws. We recently did a product review post regarding the Chick One-Lok Vise which got a lot of interest from our readers. So when we stumbled upon and were impressed by these vise jaws ... we knew we had to pass them along as well.

To quote from the Carvesmart website :
"The Carvesmart Quick Change Vise Jaw System is a complete package of front loading dovetailed jaws for production and toolroom vises that are accurately changed in seconds. Carvesmart's extruded aluminum soft jaws replace homemade jaws with a less expensive option that can be saw cut to any length."

For more information and to watch an in-depth video ... visit their website :

http://www.carvesmart.com/

We hope you find these links and information helpful ... 

along your road of Happy Chip Making !!

Please Visit our Website for More Info on all our Real World Machine Shop Software

Customer Feedback regarding our Making Chips Blog

It's always nice to know that our Real World experiences ... shared through this Making Chips Blog ... is having a positive impact on our CNC community. We want to quote and say thanks to John  Roberts for his recent post to our Facebook page.

"I recently had a major shut down issue with my fanuc Wire Edm. Not only was your informational page helpful, but guided me through solving the problem in laymens terms. I am an apprentice Mold Maker, and was thrown to the wire to my own devices. I have been operating my Wire for less than a year, and have no formal training, but solely operate and maintain my machines. With out the resources so easily afforded by your company i know with out a doubt my machine would still be down and id be sweating bullets. Thanks again for providing us joe schmoes with a little professional courtesy and help. ! Best Regards, JR"

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As Always ... Happy Chip Making !!