Mounting a Z axis Dro scale on a full size mill.

[mcostello]

I have a full size Jet mill and I want to mount a readout scale. The base is tapered top to bottom and has a generous radius that is from 2" or so on the top, to 3" to 4" on the bottom. And last but not least it has an oil pipe near the top. I need to make some brackets that would be square and plumb with the world. I was thinking of making a temporarily glued in place mold and filling it with epoxy or some such, then machining to fit. Any one have any ideas?

[Bill Shields]

Pictures?

[NP317]

Z axis DRO on the quill or on the knee?
RussN

[Rich_Carlstedt]

What we did at work and what I did on my mill at Home.
Mount a aluminum bar (say 3/8" x 2 by length) to the column
Match drill the column and the bar in two places, say 1" from each end
C'Sink the holes in the bar for 3/8" Flat heads and tap the column holes accordingly.
Now drill and tap 4 holes 1/4-20 (ie) . one on either side of the big holes and maybe almost to the edge, but still 1" from the end
Put set screws in the 4 holes and mount the bar. Moving the Flat heads in and out get you perpendicular and the setscrews can cock the bar square to the ways by engaging the curved sufaces. They basically lock in the whole bar mount. If the bars edge is not plumb, slot one of the 3/8" holes to adjust and C'sink the slot.
Now when you mount the scale it will be a simple install, using the bar as a base .....make sure it is long enough before hand

Rich

[pete]

With the way I'm reading your post this has to be for the knee travel right? That epoxy casting form could work, I think I'd want to cast some steel threaded inserts into it first though. Everybody's got there own methods that work best for themselves and what extras they have in there shop. Myself I think pre-drilled & tapped aluminum blocks would work better.

Even though it's a rough and painted casting, running the knee to the bottom of it's travel, then using a magnetic base on the table top or face with an indicator tip on the casting and moving the knee up would give you a close enough profile for an accurate taper angle per inch or foot the casting has. Cut your blocks to that angle and just under sized for depth the dro's vertical spar mounts to. Use the same epoxy dam idea to fill any unsightly gaps in so it form fits your blocks to the exact casting shape, once cured, drill through and tap the column using the holes in the blocks as a drill guide. I'm leery about epoxy and it's full strength on something like a painted casting, so I'd just use it to hold the blocks in place, provide a bearing surface for the blocks and as a gap filler. The screws would be what I'd be depending on for the actual mechanical attachment. Install the spar and again indicate it for squareness in X,Y, then shim the spar to whatever tolerance that agrees with what the dro manual says. Obviously this isn't an exact how to, but in general terms it should work for what ever mill/dro you have. Modify any of this to what will work for you.

[mcostello]

Thanks for the ideas. I'll see what develops.