TAILSTOCK CENTERING:
A good percentage of manual lathes have tailstocks that are adjustable. Tailstocks can be intentionally moved off center to cut a taper, however, after cutting a taper, the tailstock needs to be brought back in line with the centerline of the lathe to make a straight cut.

There are a couple of ways to do this: One way is to mount a test indicator in or on your lathe chuck (either with a mag base or chucking on an indicator holder) then dial in the morse taper of your tailstock quill. The morse taper should be checked with the tailstock locked down to the bed of the lathe. The morse taper should check out fairly close vertically. Front to back (x-axis) is a different story. There should be adjusting screws near the base of the tailstock to bring this back to where it needs to be. Typically these screws push the tailstock toward or away from the operator. You will have to release the tailstock clamp to make this adjustment, then re-clamp the tailstock to the bed and re-indicate. Once your indicator is reading zero from side to side you should be close enough to begin taking a test cut. Keep in mind that many lathes have beds that are worn out or twisted and the tailstock will affect the cut when it is mounted at different places on the bed.

So that if you have dialed in your tailstock close to the chuck and you start a cut on a part that requires the tailstock to be substantially further away from the chuck and you find that your part is tapered, you will have to measure the part front to back to determine how much you need to adjust the tailstock at that position. This is done by setting a dial indicator close to the point of contact between the part being machined and the live center, then adjusting the tailstock half the dimension that the part is tapered.

BUILDING A TOOLING PLATE:
I prefer to make tooling plates out of aluminum (6061, 7075, etc). I've seen people make them out of steel but these are very heavy and more difficult to re-surface. I recommend that you find a piece of material that is large enough to cover the work envelope of your mill. Do not use a tooling plate that is outside the limits of your machine's travel using a large face mill or fly cutter. Keep in mind that if you have a knee mill you are going to experience some sag in the knee and saddle, this will cause the plate to taper off somewhat at the ends of your x travel. The material should relatively thick, however, I have made tooling plates as thin as 3/4". If you cannot find an ideal piece of material, you can use 2, 3 or even 4 separate pieces that are close to the same thickness to cover your table with then machine them all to the same thickness after installation. To attach the plate to the table, you need to determine where to put your mounting holes. I measure the centerline of the outside t-slots on a mill table and layout for a minimum of 4 mounting holes. On a standard vertical turret mill, these holes would be drilled and counter bored for a 1/2" socket head cap screw leaving a minimum of 3/16" of material between the bottom of the screw head and the table top. Once you have the tooling plate mounted on the machine I recommend drilling and tapping the plate with 1/2-13 holes (or a size that fits your operation). Try to use a standard incremental grid pattern when you drill and tap your holes. I usually use 2" centers when I build tooling plates. Use caution not to break thru and machine into the mill table. This is a little bit of work up front but it will make your life easier down the road when you go to mount things on the table. An alternative method of building a tooling plate is to put the tooling plate on aluminum rails to get the tooling plate up off the mill table. This creates clearance under the tooling plate leaving room for drilling, tapping and milling thru the tooling plate. This method also shortens the z axis travel.

SOME DO's, DONT'S and MAYBE'S
* Do cut a tram line in the x-axis before you put your grid pattern in(this is just a shallow mill cut on the front or the back of the plate that will allow you to indicate it in if you ever have to remove it)

* Do - be very cautious about your z-depth when machining parts on your tooling plate. Drilled holes should go no deeper than what is required to get a hole completely thru the part so that all you will see in the tooling plate after drilling your part is a complete drill point. When you mill a part, try not to go into the plate more than .010" - .015". Your plate will have a longer life.

* Do - think ahead. Whenever you set up a job on a tooling plate that will come back (repeat) try to fixture the job with pins, pockets and/or tooling holes and try to identify the part of the plate where the job is located (engrave or stamp letters or numbers).

* Don't use mic-6 cast tooling plate. This stuff comes from the mill nice and flat but it is tremendously weak. Threaded holes won't last long.

* Don't ever press dowel pins into a tooling plate. These should be slip fit so they can be easily removed.

* Maybe - Some guys use setscrews to keep the chips out of the threaded holes. I tried this once and it was just about as difficult to get the setscrews out of the holes as it was to clean the holes out. Your choice. I will have an article in the coming months on trick ways to clean out holes (threaded or otherwise).