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Horological Milling Machine Bushing and Depthing Accessory


Product Description

About the Horological Milling Machine Bushing and Depthing Accessory

The idea for this accessory was given to us by Jerry Kieffer who is a long time Sherline user and Craftsman of the Year. The basic concept of this accessory is to use a small milling machine to do the job of several specialized clock and watch repair machines. With the Sherline mill, you can maneuver and align your clock and watch parts easily and accurately. You can also machine your parts more accurately in regards to the size and location of your bushing hole. When the machine work is done you can also use your milling machine as a manual press to insert your bushing.

Depthing attachment with a clock movement held in the two posts
Depthing attachment with a clock movement held in the two posts

This accessory also makes depthing easier and more precise, allowing you to locate your gear exactly where you want it. You can also check the gear mesh with the mating gear and then machine your bushing hole exactly where you want it to be. By using the Horological Bushing and Depthing Accessory in conjunction with your Sherline mill, you now have a three-in-one clock and watch repair machine that is also a fully functional milling machine.

Click photos for a larger view

Depthing attachment shown on a 5400 mill (mill not included). Photo courtesy of Jerry Kieffer.

The photo shows the depthing attachment on a 5400 mill. If you want to use it on a 5000-series mill you will need to add the headstock spacer block.

The improper use of machine tools and their accessories can result in serious injury. Before using this tool, thoroughly read the instructions and make sure you understand its proper and safe use.


Always wear safety glasses when operating machine tools.

Download PDF 2118 Instructions

Instructions PDF Download

21180 Horological Bushing and Depthing Blocks (2)
21181 Horological Bushing Center Support
11990 Rocker Tool Post Centers (as clamp pieces)
40330 10-32 X 5/8″ SHC Screw (4)
40660 #10 Washers (2)
1286 10-32 X 2-1/4″ SHC Screw (2)
40250 Long T-Nuts (2)
21183 Spring, 1″ Long
21184 1/4-20 X 6″ Hex Head Bolt
40550 5/32″ Allen Hex Wrench
3088B 1/4″ Draw Bolt Washer