Cutting DRO scales?

[Nick_GParticipant @nick_g]

[Nick_GParticipant @nick_g]

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Hi peoples.

I have the chance of purchasing a used but very good 2 axis DRO at a very attractive price. But the scales are longer than needed.

The scales are glass linear encoders. Sino KA-300 series ones.

Is it possible to cut the length does anyone know.? And if so what method should be used.

I know 'some' can be cut but it's the 'glass' word that bothers me.

Cheers, Nick

[MuzzerParticipant @muzzer]

If you take the end caps off (4 screws), the little bogie assembly comes out, PCB and all. That just leaves the glass scale in the extruded housing. Mine was just held in with rubber wedges or similar. It came out easily enough and I was able to use a new carbide insert tool to score the glass, then snap it off. Shortened the housing, retapped the holes and off I went.

Be aware that there is an index mark on these scales. It will work without the index but if your DRO display can pick it up (to reclaim the origin after power off – useful function sometimes), it's worth checking where it is and making sure you don't accidentally chop it off in the process!

I have some pics if you want reassurance! I shortened a spare scale to fit the head of my Bridgeport clone so I now have 2 (alternative) Z-axis scales which I change by swapping over the connectors on the display. I have to say I use this quill-mounted one 99% of the time, so it was an excellent mod.

Murray

[Nick_GParticipant @nick_g]

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Thanks for the reply.

What does the index bit look like.? – Presumably it's at one end of the glass scale.

Regards, Nick

[Brian WoodParticipant @brianwood45127]

Just a word of advice, not actually applicable in this pariticular case, but it might stop someone making a BIG and expensive mistake.

Scales used by Newall on their system cannot be shortened, they work by sampling complex eddy current signals from a carbon fibre tube containing a linearly compressed set of precision ball bearings and releasing the end cap competely destroys the scale function.

I know not everyone will be thus equipped but bought in ex-industry equipment may well have a Newall system fitted and the end caps are vulnerable to knob twiddlers and the simply curious.

Regards Brian

[GaryMParticipant @garym]

Hi Nick,

I don't know the answer to your question but there are some useful installation videos on this site which might give you some ideas.

**LINK**

HTH

Gary

[MuzzerParticipant @muzzer]

I doubt you can actually see the index mark but if you connect the display up and use the "index detect" function, you can locate roughly where it is. On my system, the display stops blinking and the unit beeps when the index is found. I think that's fairly typical.

This is what the slider looks like. The orange plastic thing is a disposable keeper. The ball on the end of the spring biases the slider against the scale. You can see three of the rollers too. It produces a classical encoder signal.

This is the extrusion with the seals removed and the scale visible. It's held in with small pieces of soft plastic beading

There's a few more pics over on this external site: **LINK** and in my albums on the ME/MEW site **LINK**.

Hope this helps.

Murray

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