# Bridgeport simmple knee dial mods for the visualayimpaired



## GailInNM (Feb 10, 2019)

First off to set the stage, I started having vision problems about 20 years ago ,  Today I have been legally blind for about a year and a half.  This means that to see any detail I need lots of light, and magnification. I have lots of overhead light and various magnification items.  But on the Bridgeport knee dialif I get closee enough to see  the dial my head blocks the  light.  

The first mod adds a tactile indication of where the zero  is  on the dial.  The photo shows it all. Under the zero a hole was drilled and tapped 2-56.  The dial is hollow so a  short screw  does not interfere with anything wen threaded into the hole. I used a 1/8  inch long pan head screw.  With  just a little bit of  practice I was easily able to get the dial within 0.005 with out even seeing the dial. Then I only had to tweak the dial a bit to zero it using magnification.  Eventually I plan to add some dedicated lighting to the dial so I don't have to use a flashlight to  do  the final setting.

Another  problem was the engraved index mark on the bearing housing.  It was difficult for me to see.  I tried fillig the engraved line with white LaquerStik and also tried polishing the black finish off and filling the engraving with white.  Neither improved the visibility enough to use easily. But, while working in this area I noticed that the the bearing housing was recessed into the casting leaving a groove around the bearing housing a little over 1/16 inch wide and almost  an  1/8  inch deep. I had to clean 35 years of grime  out  of the groove to measure it.  I cut two strips of 1/16 inch thick  XX ,7/16  wide X 3 inch long black  on white engraving stock. I put a triangular pointer  on one of the strips  and a wide black line on the other. This gave me two variations to try.  A strip was bent around the bearing housing and pushed into the groove. After trying both strips I liked the triangular pointer much better than the line. 

Gail in NM


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## DJP (Feb 10, 2019)

When I read your post I was hoping it would solve my problem too. The front bellows that protect the ways shade the index mark making it hard to see. A small LED lamp in the area may be my only solution as my mill casting does not have the groove where you placed the white strip with triangular pointer.

Have you considered using an audible signal to compensate for lost vision? In archery there is a small spring strip attached to the bow and it follows the arrow during the draw until the tip of the arrow passes and the spring strip makes a click sound to indicate full draw. With your zero screw location a spring might work to 'click' when at the index mark.

Just a thought for your consideration as we all learn to substitute other  senses when one is lost.


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## GailInNM (Feb 16, 2019)

DJP,
I  don't think that an audible signal would improve things a lot for me.   I can't think of a way that it could be bidirectional with any real degree of precision.  Also, with my touch screw I know quickly which direction is the shortest way to zero and  an  audible might slow the operation down some.  

However you got me to thinking that a LIGHT detent when the dial is at zero  might be useful.  Get the dial close with my existing screw and then complet the zeroing operation by feeling the detent by adjusting the dial.  The detent would be  strong enough to feel when adjusting the dial but week enough thet it would not be felt when cranking the knee.  Have to think on that some more.

I have the same problem as you in that the dial and index mark needs more light.  I have a tooling plate that the vices are mounted on and it extends over the operator side of the table by 6 inches.  This shades everything. Adding aLED light to illuminate the area is on the short list.  Holding a magnifier with one hand and  cranking with the other leves me  on hand short for holding the flashlight. I rigged a light and it worked OK but was too  big and I would forget  to turn it off when not in use.  As it was battery operated the next time I went to use it the batteries would be dead.  I have installed a laser pointer on my vertical roll in band saw and had the same  problem.  I built up a low  precision timer that turns the laser on for about 45 seconds and then  turn off.  I timer is push button operated and draws no power in the off condition.  I installed it about two years ago and just changed the batteries (3 AAA)  for the first time.  As the laser draws about 10 times the current that the LED light s would use I think that the same setup would work here.  I have parts for a few more timers arriving this coming week and a plan in mind for mounting the LEDS.  Should get started on this in a montoh or so.  

Gail in NM


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## DJP (Feb 16, 2019)

A single LED lamp that you epoxy to the knee casting should work. I like the timer idea.


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## GailInNM (Feb 17, 2019)

Current plan is for 3 wide viewing angle white LEDs mounted close  to the index mark. This is so a least one of the numbers on the dial will be illuminated at any time. I will mold the LEDs in a filled epoxy that contours to match the area near the dial and then mount it with double stick carpet tape os it can be removed and changed easily if I want to try something else.  Timer circuit is simple and inexpensive.  I have built several and have a PCB layout for it but I want to make a change to the PCB layout before I make any more.  PCB's are engraved and drilled on the CNC mill using a floating head engraving adapter   that I built a few years back.
Gail in NM


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## DJP (Feb 17, 2019)

Instead of a timer, a motion sensor in the same epoxy holder as the LEDs might be even simpler. Your hands moving towards the knee crank would trip the sensor to illuminate the LEDs. It would be one less button to push and no time out after x seconds. 

I'm not a fan of double sided tape especially in an oil environment. I would clean the area with alcohol and epoxy the components directly to the machine. The epoxy will be a good sealant and if you need to replace the LEDs a chisel is all that you need.

Just some thoughts for your consideration. You can go first.


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