Gadget Builder Drill Point Inspector

A 3D Printed Version of John Moran’s Drill Point Inspector

John Moran has an excellent website that details all manner of engineering projects. He is a keen advocate of four facet sharpening of drill bits and he details a Drill Point Inspector device for checking grinding results. I quite liked the concept and thought it would also be a useful asset for checking the condition of milling tools. The design uses a small inspection eyeglass magnifier lens that can be flipped from end view to side on view for tool tip inspection.

Those who know me through my blog will know that I am of a lazy disposition which tends to cause me to step back and look for an easy way to manufacture something. John’s design immediately suggested to me that a conversion to a 3D printed equivalent would be a practical solution. I also picked up on a comment that John made that you needed good light to be able to view the drill point clearly. As a result of this comment, the 3D design evolved with the addition of a simple LED illuminator. I also added a ‘right angle stop’ so that when hinged for side viewing, the lens was held more repeatably.

Because the inspector will only be used now and then, I opted for two small hearing aid batteries as the LED power supply together with a single resistor and switch. I printed two slots in the cavity for a pair of nickel silver battery contacts to sit in.

View into the battery and switch cavity. The battery contacts are bent pieces of nickel silver or tinplate

The design was modelled using Fusion 360. The two parts of the body were 3D printed. The Perspex viewing graticule was CNC milled to size and the reference comparison lines were also engraved on the CNC. The inspection lens is available from many sources on EBay (x30 21mm). The inspection screen mounting holes are 3D modelled. Here are a couple of shots of the finished model.

3D Model of John Moran's Drill Point Inspector showing the model flat for end viewing of the tool
Model hinged flat for end viewing of the tool (the LED is just visible)
3D Model of John Moran's Drill Point Inspector showing the model hinged at right angles for side viewing of the tool
Model hinged up for side viewing of the tool

Note that the addition of the LED illuminator needs the modelling of a cavity on the bottom surface of the main body. When printing this part it will be necessary to have the printer provide support structures. I also printed a cover for the cavity but this could be an offcut from an old credit card or similar thin plastic sheet.

Once printed I found the parts needed slight ‘fettling’ to remove any surface striations on the V block section, in and around the hinge section and around the eyeglass mounting slot. That aside it printed fine and the parts went together easily. More to the point it works well and is a useful tool to have to hand.

The Fusion 360 file and STEP files for the main two model parts are available in the following ZIP file. If you need additional information please get in touch.

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