boring head

	1. (Taper arbour) This is the setup to machine the jacobs taper section on a comercially available MT3 arbour soft blank. First take a light cut to straighten up the jacobs section before cutting the taper.
	2. (Taper arbour) After machinig a parallel section that will later become the jacobs taper , cut of the tang. Then, hold the arbour as shown in the picture, for drilling and tapping. The 12mm tapping is the hard work.
	3. (Taper arbour) Finally, put the arbour in the spindle taper hole, and pull up tight with the draw bar. Then machine the end of the shaft to the Jacobs taper size.
	4. (Micrometer) Threading the micrometer shaft. Diameter is 10mm and pitch is 0.5mm. The material is free cutting steel
	5. (Micrometer) Machining the micrometer shaft.
	6. (Micrometer) Engraving the scale lines with a 0.1mm width slitting saw. The depth of the line is also 0.1mm
	7. This is the slitting saw and its arbour. The best thickness for the scale line may be 0.2mm.
	8. (Micrometer) Punching the numbers on the face by hand is difficult. A punch jig makes it much easier.
	9. (Micrometer) Engraved lines can be made to stand out by filling with marker pen . An Allen head set screw is installed in the centre of the micometer head with medium lock tight to allow turning with an Allen key .
	10. (Making a special tap) Making a tap for the internal thread of the micrometer. 10mm x .5mm pitch , is a non standard metric size requiring a custom tap.
	11. (Making a special tap) Cut the flutes with a 4mm end-mill. Then grind or file the cutting edge relief angle.
	12. ( (Making a special tap)) Hardened and completed.
	13. (Body) The body is made from 55mm round free-cutting steel.
	14.(Body)Place the body in the four-jaw chuck. Find the center of the micrometer hole with the setup shown in the photograph. Bore a 17.2mm hole to take micrometer dial head and then finish rest of hole to 9.5mm then thread with custom tap.(See No. 12 )
	14.5. Tapping should be done with a 17.2mm diameter sleeve as shown in the photograph below in order to keep thread at a right angle.
	15.(Body) Dial indicate the fixed jaw of the milling vice to be parallel with the table travel. This needs to be done as the next job requires a nice parallel cut.
	16. (Body) Preparing for the dove tail cutting. Using a 12mm roughing end mill depth of cut is 8mm.
	17. (Body) The dove tail has been cut. Then finish the dove tail surfaces with an oil stone.
	18. (Sub Body) The unnecessary parts are cut away with the band saw allowing for milling.
	19. (Sub Body) Finally, the surface is machined with slow feed to produce as fine a finish as possible .
	20. (Sub Body) Drill a 12mm hole and ream it to fit boring bars .
	21. (Sub Body) Preparing for the dove tail cutting for the sub body with a roughing end mill.
	22. (Sub Body) The dove tail cutting is finished.
	23. (Gib plate) Thickness is 3mm. Material is mild steel.
	24. (Finishing) Fit the sub body to the body and lightly machine the outer surface . Then sand off all machining marks on a belt sander.
	25. (Finishinig) These are all the parts of the boring head.
	26. (Adjustment) Gib Adjustment. The left and right screw is the adjustment for gib tightness and the center screw is for locking. Completed !!