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Model Engineering Glossary: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


There are many different machines that have chucks for holding drills, mills, parts to be machined etc and many of those machines have different chucks for different purposes.

3 Jaw Self-Centering 125mm lathe chuck in the Warco WM240B - this is not a bad chuck, but after just 18 months of use it has developed some very tight spots in the scroll.

This comes with an inside and outside set of jaws and will hold a 125mm diameter workpiece with the outer jaws.

The gear mechanism that drives the scroll that drives the jaws in and out.

You can see the 3 points at which the chuck key can be located to operate the jaws using the chuck key.

Tailstock/drill chuck for the Emco Unimat 3. This is a keyed drill chuck with a capacity of 1/32" to 5/16" (0.8mm to 8mm).

As with all Unimat 3 chucks and faceplates this fits a 14x1mm nose thread.

After 35 years of use the hole for the key is rather worn and so you do have to be careful tightening the chuck.

A keyed tailstock chuck that came as part of the kit for the Warco WM240B - this is a very nice tailstock chuck with an capacity of 1 to 13mm.

Keyless chuck 1-13mm that I use in the tailstock of my Warco WM240B.

Alignment with 3-Jaw Self Centering Chucks

The 3 jaw self-centering chuck is not necessarily the most accurate. One method of ensuring repeatability is to mark Jaw number 1 with a centre line.

The black is from a permanent marker pen - gives a clean quick drying surface that is great for marking out. Also, not so permanent as you can remove the pen mark with some de-greasing fluid if necessary, it will gradually wear away over use as well.

Then mark the round bar with a line parallel to the axis and align this with the mark on the jaw. Then if you remove the workpiece for ny reason you can realign with the chuck. This works well if you want to machine the part from both ends.

Swapping Chucks

Ensure that all surfaces are clean as the smallest piece of swarf will misalign the chuck and most likely get embedded into the the surfaces and then cause ongoing issues.

See also: Collets, Lathes.

Model Engineering Glossary: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z