# Dro Pro Magnetic On Lms Hitorgue 3990



## edojan

Just want to share my installation config of a magnetic DRO pro (3 axis kit, model EL400)  on LMS 3990.

A big thanks to Joe Pitz, his post and his youtube video http://www.hobby-machinist.com/threads/little-machine-shop-hitorque-mini-mill-dro-install.36143/

This led me into the right direction (especially with regards to the Y-axis needing a separate base with set screws to correct the taper in the cast iron). I implemented this part the same way as he suggested.

The differences in my config were due to the fact that I purchased a magnetic scales / readers option (while Joe's system is optical). This required somewhat different approach to mounting the rails, the reading heads and the covers. I have also chosen to mount both X and Y reader head mounting brackets at the back of the Y axis table to allow for an easier power feed installation, if I ever wanted to install one on the left side of the of x-axis table.

The finished product looks like this:





Ok, here is what I've done: First of, I received a bunch of different brackets / bolts  as part of the kit and it took me some time to figure out how I can use them for my purposes. I ended up using modifying some of the brackets and not using others. Those parts that I used I labeled (for convenience) as brackets "A", "B" and "C"











The bracket "A had to be modified by shaving off a few mill from its top to fit over the rubber mat.

This pic shows both modified and unmodified "B" brackets




The following pic is somewhat out of place, but it hopefully explains how I used the brackets to mount the readers for X and Y axis:




 Here is a similar view with the Y covers removed so that you can see the mounting of the reader head:





A better of view of the Y-axies:




Making sure that X-axies scale is aligned with the table





Making sure the Y-axies scale is aligned




Now it is time to cover the Y-axies. I made the covers in three pieces: two short covers for the ends of the scale and one cover which would move together with the reading head (covering the head and the adjacent portions of the scale)









Here is the pics of the Z-axis
The scale mounts to the left side of the column (the fixed scale needs to be removed first) and then two "C" brackets are used to mount the reading head to the left side of the mill head.




Making sure that Z scale is aligned 





Wire slots are milled in the cover and a small wire management bracket (included in the hardware kit) installed on the inside of the z-scale's cover




This is the view from the back showing all covers installed





Regards,
Ed


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## wrmiller

Nice install. I must say that the mag scales do look like they were easier to fit than the G30 glass scales that came with my DroPros DRO.


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## edojan

thanks Bill, the relative ease of installation on a mini mill is what made me bite the bullet on the price difference  over the glass scale. I wasn't sure I had the skills to install the glass to be honest (I am a newbee to all things machining and riding a steep learning curve).  
One question on the display resolution: the dro display comes pre-setup with 5 micron res.  I have also changed the led screws to metric so everything in my setup is in mm.  When I use the DRO the resolution gives me 3 digits after the decimal - not sure if I need this much given the machine's natural limitations. I wonder if changing the resolution to 20 microns (and going to 2 digits) would make sense?


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## wrmiller

I had 5 micron scales as well, and when in inch mode I had four digits right of the decimal point. When in metric mode I had three like you do.

The mill is quite capable of giving that level of precision if the operator is capable. One time, I had a flat-head allen screw that was sticking up just a little too high on a mag funnel for a pistol. Rather than try to increase the depth of the countersink, I put the frame in the vise, came down and zero'd on the surface of the mag funnel, came up 0.0004" and milled the top of the screw off without so much as touching the surface of the mag funnel. I was quite proud of myself, and my little LMS mill. 

Not a very good pic, but this is what I used:






Your LMS mill can be very accurate within it's intended work envelope. Have fun!


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## edojan

Great! Thanks for sharing.


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