Stanley tape measure MOD (Tylon 3m 30-687; marking edge + inner dimensions)

Hi,

I'm sure you're familiar with the infamous Stanley Tylon 3m tape measure (Number: 30-687). 
They are super reliable, easy to use, get the get the job done quickly and often you can pick them up for a few bucks at most (recently I've managed to grab a few for less than 3€ a piece).

However, they have two downsides: 

1. They suck at measuring inner dimensions! 
2. And they have no marking edge! (and therefore cannot be used to perform repeated cuts with a track saw. Explanation video)

With this modification i've tried to solve both these issues.

The MOD consists of installing a simple, fixed length base plate (65mm) to the already existing screw holes of the body of the tape measure, while keeping the back-clip intact.

This adds a marking edge to the back of the tape measure and ensures that measuring inner dimensions is as simple extending your tape measure so that the hook touches one face of the inner dimension while the marking edge of the base plate touches the other and adding 65mm to the reading of the scale.

For this MOD to work you need:

1. An accurately calibrated printer
2. A caliper (cheap ones will do)
3. A bit of filament, and
4. Two M2,5 x 20mm or two M3 x 20mm countersunk wood screws. (The original screws aren't long enough to permanently hold the body together if the MOD is attached). 
   
   Important, if you use M3 screws, you might have to enlarge the chamfer of the countersunk holes with a 3mm drill bit. But be careful to not remove to much material. 

To install the MOD, simply:

1. Print the model (layer height ≤ 0,2mm)
2. Make sure the length is as close to 65mm as possible. 
   
   To do so, check the length of the print with the caliper. 
   
   
   
   If it is not 65mm either recalibrate your printer or enlarge/shrink the print in your slicer (the later could affect the fit of the model though). 
   
   By how much you ask?
   Scaling factor = (65mm - measured length) / 65mm x 100 
   
   For example: -0,3 would reduce the scaling factor in the slicer from 1,00 to 0,97, while 0,3 would enlarge it from 1,00 to 1,03)
    
3. Remove the two screws from the back of the tape measure and attach the base plate with the two larger screws.
   
   

Make sure the front edges of the tape measure and model align.



Done, that's it. Enjoy the marking edge and the impoved experience of measuring inner dimensions. 

Example marking:

Example inner measure (end to end):

Add 65mm to the scale reading: → 414 + 65 = 479 total