Making a boring head

The sliding member was machined first. The starting blank was not quite square on the cut faces, so the 4-jaw chuck was used to get all the faces at 90°.

The blank part was marked out for the adjuster hole which was then centred in the 4-jaw chuck....

......and drilled to size right through.

The milling machine was used to cut the lower.......

....and upper shoulders, as well as reducing the part to final width. Without moving the vice....

.....a 60° dovetail cutter was used to cut the angled shoulders on the parts.

The sliding member was rotated in the milling vice to be drilled and reamed for the gripping bushes which would hold the boring cutter.

The underside was sawn, milled and filed, to create the necessary under-cut.

Then the tapped hole was counter-drilled, on the drill press, before....

...the excess material either side of the nut was machined away.....

...and then the nut was rounded with a file.

The chamfer on the underside of the sliding block was machined with light cuts on the mill.

The Housing. The cut ends of the housing block were squared off in the 4-jaw chuck and then the screw hole was drilled and counter-bored to the drawing.

The mill was used to cut a slot through to the drilled hole and to rough out the shoulders for the dovetail.

The dovetail cutter was used to create the dovetail to the drawing. Light finishing cuts were used on all the working surfaces to ensure parallelism, and minimal tool deflection

A test fit with the sliding member showed a gap where the dovetails met. The problem was that the corner on the sliding block was sharper than the one in the housing.

This was remedied by filing the sharp edge off the sliding member as shown above, to get the working surfaces to meet.
The result would be a fractional offset to the threaded nut, but this could be compensated for with the front plate positioning.

Before removing the part from the mill, the housing was used to hold the gib strip for machining, in accordance with the instructions.

The housing was rotated in the vice for drilling and tapping of the gib strip screws, and also adding detents in the gib strip using the set-up shown above.

The 4-jaw chuck was used to machine the threaded hole for mounting arbor and skim the top face to final profile to ensure it was perpendicular to the hole.

The universal MT-02 arbor was put in the lathe headstock and a matching thread was machined on the open end.

The shoulders of the housing were chamfered using the mill as shown.

The arbor and housing were threaded together and secured with Loctite.

The end plate was marked out and drilled to the drawings.

The nut was a simple turning job. It was cross drilled accurately for the grub screw using the the lathe chuck clamped in the milling vice as shown.

The screw spindle was turned between centres on the lathe and threaded using a 40tpi die.

The detail on the other end of the screw was turned whilst holding the threaded section in a simple split collet, to avoid any damage.

The knob was a straightforward lathe job including knurling and cross drilling for a grub screw.

The locking screw was turned from the same piece of bar.

The screw hole locations from the end plate were transfer drilled to the housing with all the parts assembled, to ensure a perfect fit.

The brass collet clamps were turned to the plans, including the flange which would be used to hold then secure for the drilling operation* for the boring bar.

To ensure the hole for the boring bar would be parallel with the arbor the whole tool was placed in the lathe spindle and the sliding member position adjusted to get the marked hole location to run true.

To position of the sliding member was then locked using the gib strip and the end plate and screw withdrawn for the machining operation.

* The hole for the boring bar was now drilled and reamed to 3/8". This operation would also cut the required notches in the brass collets.

This photo shows a check fit of the boring bar in the sliding member collets.

The flanges were then machined off both collets, to allow them to pull into the sliding member hole, to clamp the boring bar.

This photo shows the brass collects re-fitted without their flanges.

The boring bar was cross-drilled at an angle using the set=up shown above in the milling machine.

The dial blank was turned from mild steel and mounted on an arbor to cut the conical face using the top slide.

With no dividing head, a paper sketch of the dial division was fixed to the rear of the lathe headstock and a height stand set up as an indicator.

A broken centre drill was sharpened to create a scratching tool.
The top-slide was used to create the long and short markings on the dial face.

Scotchbrite was used to polish the scratch marks back to a neat finish.

The finished boring tool.