# DRO scale on the front or back edge of the table?



## jmarkwolf (Apr 5, 2013)

I've posed the question before on other forums and got a lot of good responses, but I'm still arguing with myself while considering my options.

Front edge:

1. Loss of table stops (can be mitigated with special table stops with a "sliding pole" (ie Pineyfolks slick solution) that bumps into the ends of the saddle)
2. Susceptible to damage while loading heavy vises and tooling onto table (can be mitigated with protective angle iron)
3. Ease of installation using t-slot.
4. Sloping saddle makes it tricky to mount read head.
5. No loss of Y-axis travel

Back edge:

1. Tough access for drilling mounting holes in back edge of table and saddle for scale and read head.
2. More protected from heavy vises and tooling.
3. Susceptible to crushing while winding Y-axis (mitigated with table stop)
4. Loss of Y-axis travel.
5. Read head and/or cable getting fouled in rubber chip guard.

All suggestions and pics gratefully considered.


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## Bill C. (Apr 5, 2013)

jmarkwolf said:


> I've posed the question before on other forums and got a lot of good responses, but I'm still arguing with myself while considering my options.
> 
> Front edge:
> 
> ...



The ones I have used, in the shops I worked in, the boxes were mounted up on the right-hand side near the spindle. Assuming you are referring to a Bridge Port type knee mill. The scale and read head I think were mounted on the back side. You can make a drill guide block with a drill bushing to keep the mounting screws straight.


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## DanLins (Apr 5, 2013)

jmarkwolf said:


> I've posed the question before on other forums and got a lot of good responses, but I'm still arguing with myself while considering my options.
> 
> Front edge:
> 
> ...



Mine is mounted on the front of the table, and is covered with a 1/4" channel iron its entire length. Loss of Y movement with the rear mount seems to be a major drawback.

Dan

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jmarkwolf said:


> I've posed the question before on other forums and got a lot of good responses, but I'm still arguing with myself while considering my options.
> 
> Front edge:
> 
> ...



Mine is mounted on the front of the table, and is covered with a 1/4" channel iron its entire length. Loss of Y movement with the rear mount seems to be a major drawback.

Dan


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## wawoodman (Apr 6, 2013)

Mine is on the back. Drilling the holes was actually pretty easy. I used a right-angle drill, and backed the drill up against the column. Then, I used the table feed to apply the drilling pressure.


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## ki4byz (Apr 6, 2013)

Mount on back.
 Front will work fine but the extra work for the strong cover and to mod. the stops and lock levers just to avoid drilling and tapping 2 small holes. Yes it is tight to work in, I have installed several over the years and the only time I had to use a right angle drill motor was on my mill/drill machine.


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## Clausing (Apr 7, 2013)

I mounted my DRO on the back. If I need additional Y travel I would move the ram out to compensate for the lost travel from the DRO>


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## jmarkwolf (Apr 8, 2013)

Thanks for the responses everybody.

As much as I hate to lose any "Y" travel, I've got 12" of it, so I am going to go ahead and mount on the back edge of my Bridgeport table.

It will be a nuisance to drill the required six holes back there (one each for the ends of the scale, two for the read head, and two for mid-scale support bracket), but once it's done it's done, as they say.

Then I'll rig up some sort of Y-axis table stop so I don't inadvertantly crush the DRO scale and/or head.


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## CMAGIC0 (Apr 12, 2013)

I mounted my DRO on the back side of the table to get it out of the way. The unit that I purchased has glass tubes and with those mounted on the back side of the table and on the lower right side they seem to work well for me.    Martin


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## jmarkwolf (Apr 16, 2013)

I went ahead and mounted my X-axis DRO scale on the back side of the bed. It works well, and is more protected from load/un-loading vises and tooling on the bed.

It does reduce my Y-axis travel but I have plenty (12 inch knee) so it shouldn't be an issue.

However, now I am concerned about someday inadvertantly crushing the scale and/or head, which would be expensive. I've searched the web and have found many examples of X-axis table stops, but very few examples of Y-axis table stops for Bridgeports.

Any clever ideas out there?


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## Bill C. (Apr 17, 2013)

jmarkwolf said:


> I went ahead and mounted my X-axis DRO scale on the back side of the bed. It works well, and is more protected from load/un-loading vises and tooling on the bed.
> 
> It does reduce my Y-axis travel but I have plenty (12 inch knee) so it shouldn't be an issue.
> 
> ...



One cheap way would be to mill two pieces of stock the same length then glue them to the ways until you find or create a permanent stop. I would clean the area of oil then use a silicone glue, so you can remove it.  In all my years of setting up and running Bridgeport style mills I never crashed the scale or head.  It could be the companies I worked for may have installed a stop.  Good luck. There many talented owners/operators on here.


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## dtberry3 (Jul 4, 2013)

Mine is mounted on the front of the table.  There were no stops to remove, which made this an easy decision.  Also,  the scale is too short(12 inches)'  I  made a long t- nut to fit the slot on take front, mounted a surplus Schneeberger  slide.  The scale can slide left and right quite easily, so there are stops to prevent damage to the scale.  There  is a brake attached to the plate that the scale is on, that prevents the scale from shifting until I  desire.


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## BRIAN (Jul 4, 2013)

This is what I use on my little mill. its simple and easy to remove. takes all of 10 mins to make (thats if you are a 
bit slow like me)
Don't know if it will work on a B P though.



Brian.


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## Kevin45 (Aug 3, 2013)

If you mount the scale on the backside, if you don't have a positive stop on the column, either drill and tap and add one, or remove the existing stop and add a longer one so the "Y" axis while cranking won't run the scale into the column.

On my Lagun, the scale is mounted on front, so I have to make sure I put the vise on by standing at the back of the table so as not to set the vise on the scale. The only downfall I find with the scale on front is the loss of the table slot. I don't often use the slot, but if you have a long part and need to add holes in the ends, that slot came in very handy for toe clamping parts to the front of the table. I don't have any slot in the back, so anytime I have to drill the end of a long part, I have to square up my angle plate, bolt it down, the clamp the part to the angle plate. But the extra "Y" travel outweighs the clamping of the alngle plate.


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