CNC mill with quick tool changer

grabcad

The project started by combining two items sittings for years in the storage of my shop: An EMCO (Austrian make) milling head with column and a crude import X-Y table. Those were mounted on a granite surface plate (drilled to insert the bolts). The column was aligned to the table using toolroom granite right angle. One challenge was to convert the X-Y to a precision tool, and the other to create a very accurate sliding fit (no clamping) on the round milling head column. The column was done by lapping the housing and some other changes to the key-way guide. This is still the weakest part of the design with about +/- 3 microns side play on the Z travel.Video of lapping: https://youtu.be/Kbg2MbcFI8c The castings of the X-Y table were ground and scraped on all surfaces and C1 ball screws installed. Double shafted steppers allow hand-wheels (with scales).The tool changer is using a die spring and a hardened steel (D2) cam riding on a hardened steel nut to release the collet. Not show, but the RC60 shaft rotates in a bronze bushing.