Installing a Z-axis DRO scale on a knee mill

[GeneT45]

I'm going to install a Z-axis (knee) scale on my mill. The problem is that the column is tapered and there's a generous step between the column and the knee. I have a few ideas (and found a couple more online), but if you've done it, or your mill has a knee scale, I'd appreciate seeing how it was done.

TIA,

GsT

 

[Karl_T]

drill and tap a few spots. Put all thread in to use as stand offs. The get an appropriate sized angle iron to bolt to it. The scale bolts to the angle iron.

 

[tailstock4]

I don’t know if this is what you wanted or not, but I posted some pictures of my three vertical mills, and the z-axis scales I mounted on them. All of them have tapered main columns. The Sajo was the most difficult because it had to be mounted on the feed kickout rail. About the only thing you have to make sure of is that the scales are mounted straight as confirmed with an indicator.

I really like the knee scale on my machines. I use a Mitutoyo quill scale on the Vectrax and Acra, and a long travel 4” indicator on the Sajo quill the mounting of which was designed into the machine.

I hope this helps.

Vectrax:


Acra:


Sajo:

 

[GeneT45]

That looks like first-rate work @tailstock4 ! Thanks for the pics. May I assume that the black rail is for a power feed? How did you go about drilling the holes in the column "square"?

Thanks again,

GsT

 

[tailstock4]

That looks like first-rate work @tailstock4 ! Thanks for the pics. May I assume that the black rail is for a power feed? How did you go about drilling the holes in the column "square"?

Thanks again,

GsT

You’re correct. The black rail on the Vectrax and Acra are feed kickouts for the servo power feed. The Sajo has what I would call “real” power feed and clutched rapids. (That set up will spoil you quick.) The kick outs are built into the machine and the heavy rail that the scale is mounted to.

As far as drilling the holes straight, the Acra has a Newall DRO with their mounting system which makes squareness of the hole more irrelevant. Newall DRO’s are the easiest to install in my opinion, and they are my favorite DRO.

The Vectrax has an Acu-Rite. I just drilled the holes square with a hand drill. Then I cut one side of an aluminum block to the correct angle of the column slightly less thickness than I needed and then shimmed to alignment on the flat or square side of the block.