DRO question

T

Txturbo

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New guy with a Smithy Granite 13x24.
I want to add a DRO and the ones I’ve looked at have encoders that are way to long. Are they designed to be cut to length as needed??
 
Most are ordered to lenght. Glass scales are hard to shorten . The magnetic scales can be cut to size. Usually one orders the read out and then orders scales to fit the project. There has been some confusion over what is the lengthy of a scale in some Asian imports. I am sure that someone with more current installation experience will come on with better advice.
 
Txturbo said:
New guy with a Smithy Granite 13x24.
I want to add a DRO and the ones I’ve looked at have encoders that are way to long. Are they designed to be cut to length as needed??
Click to expand...
Generally you order them to be the next size beyond the actual travel. e.g. Linear sensors I have ordered include a 500mm long to cover 480mm of real travel. That leaves only 20mm each side spare, which is just over 3/4".

The actual physical length of these is about 140mm or so , say 5.5 inches longer than the real travel.

Yes - you can shorten them, and there is a YouTube video which shows exactly how. You have to disassemble them, and cut the metal casing to be shorter, then put the plastic bits from the end onto the shorter assembly. The etched glass sensor grating have to be shortened as well. The common method seems to be to gently grind across with a Dremel-type diamond thin disc thing , on both sides, and then gently clamping the main part between card, and breaking the unwanted piece off.

--> Cutting a glass scale for a DRO

There are others ..
DRO Scales - Making them Shorter

How to Cut (Shorten) Glass DRO scales

Take your pick :)
 
graham-xrf said:
Generally you order them to be the next size beyond the actual travel. e.g. Linear sensors I have ordered include a 500mm long to cover 480mm of real travel. That leaves only 20mm each side spare, which is just over 3/4".

The actual physical length of these is about 140mm or so , say 5.5 inches longer than the real travel.

Yes - you can shorten them, and there is a YouTube video which shows exactly how. You have to disassemble them, and cut the metal casing to be shorter, then put the plastic bits from the end onto the shorter assembly. The etched glass sensor grating have to be shortened as well. The common method seems to be to gently grind across with a Dremel-type diamond thin disc thing , on both sides, and then gently clamping the main part between card, and breaking the unwanted piece off.

--> Cutting a glass scale for a DRO

There are others ..
DRO Scales - Making them Shorter

How to Cut (Shorten) Glass DRO scales

Take your pick :)
Click to expand...
Thanks. I guess I’ll have to give it a try since all the ones I can afford aren’t the length I need.
 
For what it’s worth I cut the glass scales with my horizontal bandsaw.
I laid the scale so the glass was parallel to the floor and held the saw up so it didn’t exert pressure on the glass, just scoring action.
After a maybe 15 seconds I slowly lowered the saw and cut all the way through.
The glass in my scales was very brittle, I could nibble away at it with needle nose pliers to make the required clearance for the end cap.
 
Try a Dremel abrasive cutoff disk.
 
A gentle method is a 2mm or so copper wire stretched in a fretsaw, a little water with some #80 grit abrasive, ans a drop of washing-up liquid. It cuts a channel where to break it off. Or just keep going, adding a little abrasive as needed, until it cuts right through.

I guess the more mechanized version of this is as the @wa5cab suggestion. Just make sure both sides are suitably gently supported the whole time, to avoid a sudden break-split running back into the part of the scale you want to keep.
 
Right. Either method should work. And I forgot to add that with either method (rotary or reciprocating) you should score both sides before settling down to cut it through.
 
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