Terry Turner’s 4 Facet Drill Sharpening Part One. | Peterborough Society of Model Engineers

In the distant past (1998) when PSME held auctions in the meeting room at Thorpe Hall, Terry Turner bought an item which he knew would come in handy……one day!

About 25 years later he was proven right…!

A tool/drill holder with rotating base and inclining’V’ block, marked in degrees for precise adjustment and a strong locking mechanism.

Now bring your thoughts to 2022 and Terry is working on a 7 cylinder radial aero engine and will shortly need to create ten 1 inch cylinders. (He needs some spares). He decided to use some of the large 2 MT high quality (Imperial) Dormer drills he had acquired in the intervening years but although the drills were generally in good condition and the tapers were good, they all needed to be sharpened.

Terry looked into the best method of sharpening large drills and found many articles online about ‘4 facet drill sharpening’ which creates a drill capable of efficient material removal with much lower cutting forces.

Terry didn’t have a tool and cutter grinder and did not want to go to the expense of buying one and wanted to avoid the time taken to build one from a kit, so he decided to use items which he had in his workshop to build a drill sharpener.

Required…1. A bench grinder with correct grinding wheels.

2. A small X, Y milling table.

3. An accurate drill holder.

The key to 4 facet drill sharpening is accuracy of drill position and repeatability.

It is essential that the position/grind on one side of the drill tip is precisely replicated when you rotate the drill through 180 degrees to grind the opposite side of the drill tip.

More to follow…….