I have a Bridgeport knee mill 1970 with no DROs. I do some fly-cutting that requires that I be VERY accurate with height (quill) settings in order to make sure I maintain thickness requirements.

I would like to add a quill DRO or digital scale, but all that I can find have a resolution of only 0.0005" with an accuracy of +-0.001". This is still too rough. I would prefer a resolution of 0.00005" or 0.0001" and an accuracy no worse than +- 0.0002".

I have found the Mitutoyo quill DRO and many Chinese versions, but all of them have no better resolution.

Is there something better out there? Should I be looking at glass scales and a seperate display as a solution?

Any help would be appreciated.

Andy
amasters@customthermoelectric.com

Come on guys...any help would be appreciated.

Even a shop/provider that can answer my questions and perhaps even sell me the Quill DRO solution I need.

Thanks

I don't know of any high precision quill scales, but I haven't looked hard either :D I can imagine it might be quite a hassle to mount a glass scale up there. Heat growth of the spindle might even affect trying to stay inside those tolerances.

What kind of tooling and what kind of operation are you doing? Is there any way you could use a scale on the knee instead of on the quill?

Maybe another method would be to rig up some kind of a stop system on the quill, wherein you could place a stack of gage blocks. Nowadays, a person can find relatively inexpensive gauge block sets suitable for shop use as opposed to worship use :D

Hello Andy I have a Bridgeport with a Quillstar Mitutoyo scale on the quill it is very accurate to 0.0005" and I use it frequently for putting a cut on as it far more accurate than the knee,to get any more accuracy is going to be quite a challange, 1, Fly cutting is not the most accurate form of machining as even the back cut will probably take off more than a couple of tenth's due to spring in the tool, this is on the assumption that you can tram the head square enough to tha level of accuracy, 2, I have seen slim glass dro scales on a Bridgeport quill but to get the feel using the hand wheel and the feed clutch engaged in the neutral position will take some very light touch and a near perfect quill rack and pinion fit to maintain that accuracy. 3, And lastly I doubt even Bridgeport would say that you could get that sort of accuracy on even a new machine. Hope this does'nt destroy your attempt at the level of accuracy you are after but I think you are on a hiding to nothing to repeat it. Cheers Colin