While the linear encoders may be better for the purposes of this list I
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think the question is really: 1 - Is my machine such that I would notice any difference? 2 - Even if I could notice a difference is the cost/benefit at a point that makes sense for me. I run my Bridgett my Bridgeport series II on Gecko G320 drives with rotary encoders on the motors. The accuracy and precision with the rotary encoders is more than adequate for my purposes. It will easily hold to less than .001" and I can sell all the stuff I produce on the machine. Spending the money to upgrade to linear strips would buy me nothing as the items I am producing would not become any more valuable and no one would pay more money for then. It is all a balancing act to get the accuracy and precision needed and not waste money getting more. Also remember what the rest of your machine is capable of. Putting on super high resolution linear encoders on a mill drill conversion is probably a waste as the rest of the machine will have enough play and flex that you will not likely see an improvement. Also remember that setup of the part can have a huge impact on machining precision. A weak setup will introduce more inaccuracy than the difference between linear and rotary encoders. Ditto with thermal expansion. So, if you are not using flood with the coolant being held to a relatively constant temperature than you will also have inaccuracy. In summary, my point is that you have to consider the whole and not just focus on one part. Like so many things in this hobby it is easy to get into a pissing match where the claims of what is required no longer fit the reality of most machining much less hobby machining. So if you really feel your setups will be rigid enough to allow machining to .0001" and you will control the temperature, and your machine is capable of moving that small an increment, than maybe the linear encoders will make sense. Tim [Denver, CO] ----- Original Message -----
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