# Cutting Glass DRO Scales-How to...With Pictures



## Kennyd

In my recent DRO thread: http://hobby-machinist.com/index.php?topic=2019.0 a comment was made stating "You cannot cut glass scales". Well, after some research I have found that indeed you can, and I did two of them today.

Here is a simple How-To on how I did it. First let me state that it is not for the faint of heart, but there where no surprises and everything that happened was predictable.

-First, I removed the endcap opposite the labels so they would remain intact, slid the reader head out, then I pulled out the 4 wipers. 

-I determined that the glass was glued in (some scales it's not) and that I did not want to try removing it from the scale body, so a packed a paper towel around it to give it support during the cutting process. Then I proceeded to make a test cut, and since I had to shorten it by 15 inches I had plenty of trial and error room.

-After the test cut proved un-eventful, I cut the scale to the final length. When the blade hits the glass, it breaks in a fairly straight line, but this is NOT critical anyway since it must be trimmed back about 1/4" and the reader head is still over 2" away at it's closest point. For the trimming I just reached in and nipped at the glass with needlenose pliers since nothing else could get in there to trim the glass. Remember this is non-critical.

-Next I filed the end of the body to remove burs, Then I taped the endcap on and used a transfer punch to mark the holes for the endcap screws.

-Next I drilled the four holes-this was the most stressful part worrying about the bit breaking. The I proceeded to tap the four holes with a 2mm tap.

-After all the cutting/drilling/tapping was completed, I removed the paper towel and used compressed air to clean ant debris from inside the scale body.

-Then I slid the wipers back in and cut them with a razor blade, then re-installed the reader head.

-The last step is to apply a small bead of silicone around the endcap and install it using a dab of Loctite on the four screws. 

All this took a little over 1 hour to complete, and things went so well I decided to cut down the compound slide also by 2" since it's going to be hanging of the rear (see other thread linked) I figured the less mass/length the better.


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## Kennyd

Four more pictures:


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## Kennyd

Thanks Ed, consider thy butt "covered" ;D

The pictures worked last night before the set was offline for a while. The are not links but rather attachments uploaded to the posts. Possibly something wrong on the site after the maintenance?


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## Kennyd

Pictures re-loaded


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## Bobby Bailey

Good write-up. Thanks,
Bobby


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## RandyM

Yup, nice job Ken. I will have to book mark this one. Thanks for the post.


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## Kennyd

The install has begun, updates in this thread: http://hobby-machinist.com/index.php?topic=2937.msg20428#msg20428


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## tdrago

Just wanted to clarify what I read here...so you cut the glass with it in place INSIDE (still glued in place) the aluminun housing and just hacksawed the entire scale ???  Photos look like you did it with the housing/glass in the upright/vertical position so the glass was cur downward on its edge ...is that correct ??  Would have thought cutting it on the larger flat side (horizontal position) would have been less risky.....  just a regular hack saw blade ???  Please fill me in..Thanks. TD


-I determined that the glass was glued in (some scales it's not) and that I did not want to try removing it from the scale body, so a packed a paper towel around it to give it support during the cutting process. Then I proceeded to make a test cut, and since I had to shorten it by 15 inches I had plenty of trial and error room.

-After the test cut proved un-eventful, I cut the scale to the final length. When the blade hits the glass, it breaks in a fairly straight line, but this is NOT critical anyway since it must be trimmed back about 1/4" and the reader head is still over 2" away at it's closest point. For the trimming I just reached in and nipped at the glass with needlenose pliers since nothing else could get in there to trim the glass. Remember this is non-critical.

-Next I filed the end of the body to remove burs, Then I taped the endcap on and used a transfer punch to mark the holes for the endcap screws.


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## Kennyd

tdrago said:


> Just wanted to clarify what I read here...so you cut the glass with it in place INSIDE (still glued in place) the aluminun housing and just hacksawed the entire scale ???  Photos look like you did it with the housing/glass in the upright/vertical position so the glass was cur downward on its edge ...is that correct ??  Would have thought cutting it on the larger flat side (horizontal position) would have been less risky.....  just a regular hack saw blade ???  Please fill me in..Thanks. TD



Yes, scale is glued in, cut just like the pics showed.  Just a regular metal blade in my bandsaw.


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## Splat

I'm necroposting  to say thanks for posting this. I've got a SINO DRO package I bought used. One of the scales I got with the SINO is about 5" longer than what I need for my cross slide. So with help from the info you posted here I'm going to cut it down to what I need. Wish me luck!


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## FLguy

Kennyd said:


> In my recent DRO thread: http://hobby-machinist.com/index.php?topic=2019.0 a comment was made stating "You cannot cut glass scales". Well, after some research I have found that indeed you can, and I did two of them today.
> 
> Here is a simple How-To on how I did it. First let me state that it is not for the faint of heart, but there where no surprises and everything that happened was predictable.
> 
> -First, I removed the endcap opposite the labels so they would remain intact, slid the reader head out, then I pulled out the 4 wipers.
> 
> -I determined that the glass was glued in (some scales it's not) and that I did not want to try removing it from the scale body, so a packed a paper towel around it to give it support during the cutting process. Then I proceeded to make a test cut, and since I had to shorten it by 15 inches I had plenty of trial and error room.
> 
> -After the test cut proved un-eventful, I cut the scale to the final length. When the blade hits the glass, it breaks in a fairly straight line, but this is NOT critical anyway since it must be trimmed back about 1/4" and the reader head is still over 2" away at it's closest point. For the trimming I just reached in and nipped at the glass with needlenose pliers since nothing else could get in there to trim the glass. Remember this is non-critical.
> 
> -Next I filed the end of the body to remove burs, Then I taped the endcap on and used a transfer punch to mark the holes for the endcap screws.
> 
> -Next I drilled the four holes-this was the most stressful part worrying about the bit breaking. The I proceeded to tap the four holes with a 2mm tap.
> 
> -After all the cutting/drilling/tapping was completed, I removed the paper towel and used compressed air to clean ant debris from inside the scale body.
> 
> -Then I slid the wipers back in and cut them with a razor blade, then re-installed the reader head.
> 
> -The last step is to apply a small bead of silicone around the endcap and install it using a dab of Loctite on the four screws.
> 
> All this took a little over 1 hour to complete, and things went so well I decided to cut down the compound slide also by 2" since it's going to be hanging of the rear (see other thread linked) I figured the less mass/length the better.
> 
> View attachment 18879
> View attachment 18880
> View attachment 18881
> View attachment 18883
> View attachment 20745


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## FLguy

In an other hobby I enjoy; lapidary, I would use my diamond saw. It has gushing water to keep things cool and free of swarf. A great finish and really cuts faster than one thinks it might.


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## Steven4HIM

Hey Kennyd, thank you for your post.  I have been wanting to do this for a long time but just couldn't get up the nerve to do it.  I installed an X and Y DRO setup on my mill and had a couple glass scales left over which I wanted to use for the Z axis but the scales were too long and I just didn't know how to do it.  I watched a few videos and saw that it could be done but again, could not get up the nerve.  Long story short, I saw your post with some good pictures and it all of a sudden seemed doable.  So I went at it.  I measured, pulled off the end cap, pulled out the reader head and the protective wiper strips.  I stuffed in some paper towels to sure up and reduce vibration on the glass strip which I believe in mine was not glued in, it looks like there are just some rubber pieces that wedge it in.  
So I do not have a band saw with a metal blade so I went with using my 14" metal cutoff miter saw.  Definately not the most gentle cutter, as a matter of fact, it vibrates and is pretty violent compared to a band saw, but it is all I had.  I took it slow and let the saw do the work.  Well it cut it perfectly, the edges of the aluminum was a bit rough but the glass cut perfectly with not chips or nothing.  It cut out about 1/4" of my scale but it worked!  I sanded down the edge and cleaned up the burs and then took my snub nose pliers and chipped back the glass a tad for the end cap to fit on.  Now I am just waiting for my 2mm tap to arrived from Amazon and I can tap the new screw holes for the end cap.  I did put my reader head back in to make sure it still read ok and it seems to still work just fine.  So thank you again for your detailed post and will get this thing installed soon.  Gotta fabricate something as well to connect the reader head with the Z axis.


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## DavidR8

I cut my glass scales with my 4x6 saw. I didn't remove the wipers as I wasn't confident that I could get them back in place. Didn't remove the glass either. Just marked for length and went to town. 'Trimmed" the glass back using needle nose pliers so the end cap would fit. 
Worked like a charm.


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