I am perhaps a bit more tolerant than some of the guys here on the subject of following the board's rules. I do try to follow them myself, but I try to, at least steer the new guys in the right direction. So, yes this board is intended for professionals and their questions and the discussion of hobby style equipment and it's problems is not encouraged or tolerated. There are a number of boards for such discussions and you will be welcomed there. And many of the members here are also on some of those, less professional boards. So the help you will get there will be no less valuable or accurate. The needs of professionals are different from those of hobbyists and dare I say, that in some cases' it will be more so. One that I recommend is:
General -
The Home Shop Machinist & Machinist's Workshop Magazine's BBS
As for your lathe, there are two approaches that I can see. The first is to reduce the height of the tail stock as has been suggested. The other is to use some shims to increase the height of the head stock. I am not very familiar with the details of those two components of the mini lathes so I can go no further with those two ideas. I do know that there are other situations where the head stock of a lathe has been increased by using a riser block. This has the advantage of increasing the swing so larger parts can be machined.
But you ask about how to measure the difference. I am sure there is more than one way. One that I may suggest that would not require more than simple measurement tools would be to remove the compound from the cross slide and use the top of the cross slide as a base for the measurements. Move it under the headstock spindle and then use a caliper to measure from the top of the cross slide to the bottom of the spindle. Then, measure from there to the top of the spindle. Add the two numbers and divide by two to get the height of the center of the HS spindle from the top of the cross slide.
Now move the tail stock over the cross slide and lock the tail stock and it's quill to prevent movement. Do the same two measurements on the tail stock quill and add them and divide by two.
The difference in the two measurements is the difference in the two heights.
Vernier, dial, and digital calipers all should be capable of making these measurements. A spacer block of known dimension may make the inside measure easier: A set of imported 1-2-3 blocks are inexpensive and have a lot of uses in the shop. Whatever you use, do check the actual dimension.
As to weather it is best to take off too little or too much depends a lot on just how you would resolve the remaining amounts and how accurate you will want the final result to be. A good shop should be able to keep the new surfaces parallel to the original ones to well under a thousandth. I doubt that the original accuracy of those surfaces were done to that level.
I bought a no name chinese minilathe off EBay a year ago, never got around to setting it up until recently. with a live center in the tailstock and another one in the headstock chuck, the tailstock one is about 3/16" higher than the one in the headstock! I got another tailstock from little machineshop. it lacks the removable base plate of the original and is just as much too high! so I GUESS that I have to have a local shop mill the 3/16" off of the underside of the baseplate, (to include deepening the v-notch that fits one of the lathe ways.
Assuming that is what has to be done, how do I go about getting a precise measurement. ? I ASSUME that I"m better off machining off a bit too much (and needing to shim it up) than to cut off too little and have to machine it AGAIN. Am I correct in that assumption? Thanks guys.
I guess I'l have to use my machinit's level and some flat pieces, like files, to get the measurements?
