TEC Chuck Jaws

Technical Help and Tips

If possible always bore or turn soft jaws at the same chuck pressure that you clamp the work piece. One easy way to do this is with the TEC Trueborer.


Serrated jaws generally offer more positional flexibility than slot and tenon style jaws. However slot and tenon jaws usually have a fixed position and hence offer the likelihood of attaining good repeatability more frequently if removed from the base jaws.


Replacement hard reversible jaws may not be as accurate as the original jaws supplied with the chuck because the originals would have been ground on the chuck under clamping pressure. To attain the same concentricity the replacement jaws would need to be ground or hard turned under pressure on the chuck in-situ. Generally, replacement jaws are used to clamp un-machined surfaces and a slight run-out is acceptable.


Hard jaws or soft jaws? Generally soft jaws are used for second operation work on a machined diameter or where teeth marks cannot be removed. Hard jaws offer safer and more arduous machining with the teeth biting into the material (see the Adjustagrip ranges in the catalogue).


Save time and keep your T-nuts loosely attached with each set of jaws when off the chuck. It is very quick and easy to position this loose unit on the chuck when changing sets reducing costly set up time.


When the work piece is gripped, the jaw stroke should always be at mid-stroke especially when boring or turning soft jaws. Hard jaws can be used with more or less, but a safety margin of a quarter of the stroke should always be maintained.


Always adhere to the manufacturer’s manual and grease chucks regularly as this has a big impact on clamping forces and it will also affect repeatability, operator safety and the longevity of the chuck.


If large or heavy jaws are used, be sure you are within the guideline limits outlined in the chuck manufacturer’s and our own our technical information. Large jaws and work pieces can severely affect a chuck’s performance and cause unbalanced and dangerous conditions.


If you have any points you are uncertain about, please call our sales office and we will be pleased to help you.