Sony LH51-2 Lathe DRO system questions

[techymechy]

I purchased a used Sony LH51-2 with two SR128 scales. Everything works as it should, however the SR128 scale that is supposed to go on my cross slide (X axis) is way too big for my little Logan 400 lathe. The Z axis scale is just fine.

I really don't fully understand how these DRO's work, but is there a smaller mag scale (say, like Ditron) that would work with my Sony LH51-2? Some of the scales made today are really small and could actually fit my lathe w/o affecting the limited travel distance or interfere with the follow rest attachment.

Please let me know if you think that I can substitute a different manufactures scale for my Sony SR128 scale. If you think that this is possible, please make some suggestions for the scale.

Thanks,


Dave

 

[techymechy]

Well, I actually found an article that discusses servicing and adjusting of the preamplifier on SR128 scales. I'm pretty confident that this is a no-go. The Sony wave form is actually really complicated (looks like 2 sin waves, 2Vpp, 50kHz superimposed on each other and 180 degrees out of phase) as opposed to the typical square wave scale wave forms. Shoot - I can't use this wonderful Sony DRO. I guess I'll have to sell it on eBay or something.

 

[Billtodd]

As Dave says, the sony uses a relatively long wave length sine signal and uses quadrature interpolation to produce the accuracy. It is not at all like the typical 'ttl' scales used by most manufacturers (although, the newall system has some similarity , and the more expensive hydenhain F series also use analogue quadrature).

Sony make (or made) the scales in various sizes so check ebay for a shorter one .

 

[techymechy]

Hi Bill,

Thanks for the reply. My unit is for a lathe. I bought this from eBay and it was my first DRO purchase. The X axis scale is way too bulky to fit on my Logan 400 X axis. My DRO works wonderfully well, but it just won't fit (my current X axis scale is too bulky and a bit long).

I haven't ever sold anything on eBay before. I guess I'll try to sell this one.

Dave

 

[rklopp]

The Sony X scale I got second hand for my Chipmaster was also too long and bulky to install alongside the cross slide, so I got creative and stuck it out the rear. I thought about shortening the scale but found the scale is a steel strip held in tension by the housing, and the strip is spot-welded in place at the ends. I can't find the CAD files of my brackets, which I designed back in 2014. I would not have done this if the DRO wasn’t super-cheap and the lathe was newer.