[How do I?] Advice Needed: 3 Axis Dro Kit For Sx3 Milling Machine

Darren

Darren

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I am thinking of buying one of these 3 axis DRO kits for my SX3 milling machine...

http://www.ebay.co.uk/itm/3-axis-di...ete-DRO-kit-/320919811363?hash=item4ab84fb523

Obviously there will be no machine specific instructions with this kit so i am looking for advice on the best way to mount it all.

Has anyone here got this or a similar kit fitted to an SX3 machine? If so i would appreciate some photos of how it has been mounted, brackets etc? What 3 sizes of scales are recommended for the SX3 machine?

Any other advice regarding fitting this kit to the SX3 machine would be great.

Thanks
Darren
 
Darren,

Nothing specific to your machine but I have mounted two three axis glass scale DRO's on mills. Ideally, you will select a location for the scales that does not interfere with operating capability. The scales should be mounted with the pickup on the bottom side of the scale to minimize possible contamination.

The scales are fairly generic and if you look at a site like DRO Pros, you can get a fairly good idea of how long each scale should be.
http://www.dropros.com/Digital_Readout_DRO_Scale_Sizing.htm

When mounting the scales to the machine, you should have a flat surface for mounting each end and those surfaces should be coplanar. If not, use an intermediate mounting plate. Castings have a taper due to draft and this should be considered when mounting. On on mill, I mounted the x axis scale on the front on a piece of ground flat with standoffs to clear the power drive limit switches. The y axis was mounted on a bar machined from 3/4" x 2" aluminum and mounted to the end of the x axis ways. The y axis pickup was mounted to the mill base with a tapered adapter to correct for the draft.

Generally speaking, I made my own mounts instead of using the supplied hardware.

One thing to consider when selecting a vendor is what kind of support you will get with the DRO.

Bob
 
I agree with everything Bob said. I mounted a similar kit from the DROStore on a round column mill a few years ago and am now moving it, (with new scales) to a Bridgeport.

When mounting the long scale part, indicate it in along its full travel length so it runs true to its ways. Leave the reader piece attached with the plastic shipping mounts while you set up you reader support brackets. Shims, wedges, spacers, whatever is necessary to match up to the reader before bolting in place and removing the shipping spacers.

Sometimes the scales and readers can be quite some distance from the object whose movement they're measuring. Quills can be tricky like that. That's fine as long as the mounts are solid and move true. I've seen some very inventive ways of hooking up scales and keeping them out of the way of all the levers and wheels. :)

Also, I had a little difficulty zeroing out the end to end error once set-up. There's a parameter that needs to be programmed into the DRO unit to account for minor variations on the glass scale etching. The math in the installation guide was very wrong. So watch out for that.

All in all you should be quite happy with the added sense of ability the DRO will provide. I was.
 
I took a look at your mill and it is fairly small for glass scales. Keep in mind that mounting the x axis scale behind the table will most likely impair your y axis travel. It looks like you could mount the scale on the front side. The y axis looks OK on either the left or right under the table. For the z axis, you will need could get creative. Most likely , the scale would locate on the front or to the left an a mounting plate. I made a custom pickup adapter which fit the end of the quill. Unfortunately, I can't locate the assembly model (it was several years back at work and since retiring, I no longer have access to those files.

If you have difficulty in locating suitable mounting arrangements, you might want to consider the iGaging type scales. They are more compact. You will give up some performance in that they are 10 micron scales and don't have the resolution of the glass scales and the readouts don't have all the features of the one you are looking at.
Here is a link for an SX3 DRO install.

http://www.mini-lathe.com/X3_mill/dro/dro.htm

Bob

Z axis quill adapter.JPG
 
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