Schaublin Dials, why are they backward in X and some are Radius instead of Diameter

[laminar-flow]

After dealing with my Schaublin 70 English dial reading the material removed diameter instead of actual diameter of the part, (I would always use it to show diameter of the part by thinking of a 8 as a 2 and a 6 as a 4, etc.), I finally made a new X dial. I also have a Metric Slide and not only does the X dial read in material removed but it is in Radius. So I made a Metric dial and engraved it to read in diameter of the part. The Metric screw is 1mm pitch so the dial has 100 divisions and when turned CCW, (larger part), every 5 divisions proceeds as follows, 0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0 ~ which is one revolution. It was quite a project for just a few but will be worth it.

Does anyone have any idea why Schaublin used dials like this in X? The same dial can be used on the X and Z but I can't believe Schaublin did that to save money. All my CNC and DRO read in diameter of the part. I don't care how much fuel I have used, I need to know what is left in the tank.

 

[jim rozen]

My 70 slide has same as yours - lathes are subtractive machining so they typically read 'how much comes off when you crank it in.' Long' feed has different dial as it reads 'how much does it move along the bed.' Save the old dial, somebody will want that someday and you could make some $.

 

[Conrad Hoffman]

I've never used a lathe that didn't work in "material removed". Some lathes, like my Logan, have very small dials. My guess is the graduations would be too close together if they referenced diameter, so they work in radis, IOW, direct tool travel. That's why dial upgrades are so popular for old Logans and Southbends.

 

[dgcope]

I always thought that the diameter vs. radius dials were based on a tradition difference. Imperial lathe cross slide dials indicate diameter and metric lathe dials indicate radius. Obviously there are exceptions. My Schaublin lathes (one metric, one imperial show this difference)

 

[Screwmachine]

The 102 slides I've used in inch were radius, maybe the larger Schaublin machines move to diameter in inch?

 

[laminar-flow]

I can't remember a lathe that was radius and material removed until I got my 70 Schaublin Metric Slide. We also have a metric 102 slide that is radius material removed and it could only be used with a calculator. The 102 was converted to DRO to read diameter of the part and now is a dream to use. If drawings were in radius and micrometers in radius I guess that would work, but calculations would still be needed if it read in material removed. With my other lathes CNC and 10EE with DRO, they read in the diameter of the part. When setting up the Haas CNC, no tool setter, you skim the work, measure diameter of what you just cut, press X offset, and it prompts you to enter the diameter you just measured. Same with the 10EE, skim a piece, measure, and enter in the X. Then make a datum for the tool number in the DRO.

 

[wesg]

Don't remember which, but one of the lathes i used years back was radius. Just fine if you know nothing else.

My SAG-12S is diameter, .400 per turn. The standard dial practically needs a microscope to read. The optional large dial is just fine, but interferes with the compound in some situations.

With the DRO, I still use the dial for roughing passes, and glance at the display for confirmation.

 

[laminar-flow]

After two months of used the reversed Schaublin dial I can only say that it makes quite the difference. Yesterday, I had ten parts that need to be bored to .150 and .165 ID and it was so nice to take a skim cut, measure with a pin, set the dial, then proceed without ever checking anything again. So nice. On every part the slide had to be backed out to drill and set back to the exact number to make the bores. No need to continually measure except after they were all made for a QC check.