Lathe V Ways Calculation for fitting Tailstock and Carriage _/\_

While rebuilding the Chipmaster, the problem of aligning the carriage bed ways ( bottom slide ) and top slide arise, from what information I can find these have to be at right angles. The bottom slide is worn bananas, so a simple spotting technique, on the bed might cause a lot of headache later to align the cross slide. So I decided to align the tail stock base first, and then use it on the lathe to check which original sufaces on the crosslide are closest to allignment, to be used on the mill setup.  I will then cleanup the V groves at the bottom, and do the final spot checking on the lathe beds. So the approach requires three steps.
1) Align the tail-stock on the mill, and touch-up the V slot, and flat surface. Machine one outside surface parallel to the V-Groves. Final fit on the lathe with transfer spotting.

2) Find the best reference surface on the carriage with the fitted tail-stock base as guide. Or bolt an adjustable bar to the back, where the taper attachment usually attaches.

3) Machine the cross-slide base V and flat ways, aligned to identified surface. Fit with transfer bluing.

The calculation for the depth of the V slots require similar math to that used for dovetail calculations. I used two 14 mm end mills as gauge pins, the bottom circle is used for measuring the depth, when the base is upside down on the mill, since I want to do the machining in one setup.

Height with14mm gauge pin in V slot, should be z higher than flat surface          
              
On the drawing, the top two 14mm gauge pins are used to  measure the_ /\_ ways, the
bottom gauge pin is used to measure height over the flat surface, for a level tail stock base.          
              
map the flat surface to find low points, add z, mill out v until this height is reached          
mill down flat surface         

                 measured    38,515    across pins
c1,c2,c3    r    7   
                 a    24,515    measured-2r
                 b    4,949747468   
                 c    2,050252532    r-b
                2d    14,61550506   
                d    7,307752532   
                h    9,358005063    c+d
               w    18,71601013    2*height
               e    9,899494937   
              c3    center    0,541489873    e-h
              z    7,541489873    r+c3 center

Oil grooves for sliding surfaces on Machine Tools / Ölschmiernuten für Gleitführungen an Werkzeugmaschienen

My ongoing quest to restore the Deckel FP2, Chipmaster and Eagle surface grinder, makes you deep dive into Machine tool design frequently.

Once the castings where back with shiny new precision ground sliding ways, the question comes do I improve on some of the shortcomings, like no oil grooves? Or leave it factory standard? Well this is probably one of the main reasons why I decided invested in old machine tools, the new machines from china also require a fair amount of work to perform consistently and last for some time.... Might as well spend the time on an old machine tool and in the process learn the trade.

Well back  to the topic at hand, how to cut the oil grooves inside dovetails? There are various tidbits on the web giving advice, but nothing seemed elegant and time efficient. As example one could spend a lot of time with a precision setup on the manual milling machine to engrave oil grooves. Or a setup on a CNC. Or use a hand held dremel like tool, or use a custom ground scraping tool.

When you consider the options, it becomes apparent why a lot of old machines, have very simple oil grooves like elongated Z's,  straight connected 0's, long straight slots with perpendicular grooves similar to I. A few examples shown below.

But we know better, there is a great book by M Weck ( Werkzeugmaschinen 2 - Konstruktion und Berechnung ) Pg 245 it shows some examples and the form which shows best performance, a trapezoidal zig zag form (figure 1 below) When you think about what happens to the viscus fluid while the slides are sliding across one another back and forth, this almost acts as a staged pump.  The pumping action helping the spread of oil, since it can not run back along the inclined grooves. The one thing my research did not find is the best angle for the inclined grooves. The angle needs to satisfy two opposing requirements, retain as much oil to evenly spread on the opposing slide, 2. feed oil to the next stage. My starting point is 25͒͒͒͒͒͒°, lets see how this goes.

Now once the form is selected, the down side is this form probably is the most complex to produce. This made me go in search of methods we used before machine tools, and the result is a simple tongue and grove planer with a special ground tip.  Below take one on such a tool, for 60° dovetails. The angle might vary on your specific requirement, but I can see a use in inverted V slides used on the lathe and in square columns used in the Deckel.