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Instruction/Data Sheet

In this booklet we will take an in-depth look at the 

Robert Sorby

  Eccentric Chuck with all its 

component parts and make 4 different projects. The four projects are of varying complexity and use all 
of the Eccentric Chuck’s various holding methods.
The first project will be an Off-set Stem Goblet. The second will be a 3 sided bowl with a cloverleaf 
centre detail. The next will be a Cabriole Candlestick and we will finish this presentation with a  
scallop lidded box.

The 

Robert Sorby

  Eccentric Chuck uses three methods for holding the wood.

These are : 
1.  

Screw chuck

2.  

Faceplate

3. 

Hexagonal Ball drive and socket.

The 

Robert Sorby

  Eccentric Chuck is the most comprehensive multi-centre chuck available.

The unique eccentric boss provides easy and accurate adjustment with its bi-heaxagonal locating 
socket for each of the holding components. This allows for each component to be located at any  
of the 12 positions.
The eccentric boss is marked 0-35 on its outside diameter, which can be seen through the viewing 
window in the main body.
These markings are the amount the holding component held in the eccentric boss can be offset  
from centre. 
Zero being on the centre axis of the lathe. At this position the work piece will run concentrically to the 
rotatation of the lathe.

 

Any number other than zero will then offset the work-piece by the amount shown in the viewing 
window. The combination of the amount of offset of the eccentric boss & the position in the 
bi-hexagonal socket means this is the most versatile Eccentric Chuck available. 

The 

Robert Sorby 

Eccentric Chuck weighs around 51/2 lbs (2.5kgs). It is designed this way 

to counterbalance the weight of the work piece when it is offset. This gives more stability than any 
other offset system where the main components are offset from the centre as well as the work piece, 
adding far more weight and creating a greater imbalance. This would substantially reduce its capability 
increasing the risk of damage or injuiry.

Using and insterted adaptor system with a large variety of thread sizes the  

Robert Sorby 

Eccentric Chuck can be fitted to virtually any lathe in the world. 
The insert, screws into the main body of the chuck and is tightened using the large wrench supplied.
The chuck can be easily mounted onto the lathe and is tightened using the wrench supplied. 

The  

Robert Sorby 

Eccentric Chuck is also supplied with comprehensive 12 page instructional 

manual. It describes the chuck and its component parts as well as instructions how to use each of the 
holding methods. A CD video to accompany this booklet is also available. It shows all the procedures 
described with full step by step commentry.

Page 1

Robert Sorby  

Instruction/Data Sheet

ECCENTRIC CHUCK PROJECTS

Summary of Contents for Eccentric Chuck

Page 1: ...rotatation of the lathe Any number other than zero will then offset the work piece by the amount shown in the viewing window The combination of the amount of offset of the eccentric boss the position in the bi hexagonal socket means this is the most versatile Eccentric Chuck available The Robert Sorby Eccentric Chuck weighs around 51 2 lbs 2 5kgs It is designed this way to counterbalance the weigh...

Page 2: ...ithout any inteference Check this by rotating the wood or work piece by hand before switching the lathe on Safety equipment As with all woodworking sufficient safety equipment should be worn A very minimum of a pair of safety glasses and a dust mask is essential but when turning off centre a face shield is highly recommended Please read the step by step instructions very carefully attempting any o...

Page 3: ...tre we will reduce the speed of the lathe for safety It can be increased with confidence and experience Switch the lathe on and watch the wood spin to understand what the wood is doing now it is rotating off centre Care must be taken when turning off centre work Approach the wood very carefully and allow for the fact that you will only touch the wood in one place on every rotation Place the cove c...

Page 4: ...t off it isn to the right hand side of the original safety mark Be careful when parting off that the goblet does not come loose Only part all the way through if you have experience and confidence to do so if not part a small way through and finish with a saw Check and finish the base and proudly display your Off set Stem Goblet Robert Sorby Instruction Data Sheet ECCENTRIC CHUCK PROJECTS ...

Page 5: ...ce of the blank in the safe toolrest position Turn the face of the blank flat Place the toolrest at the safe toolrest position at the outside of the blank Turn the face with a small bowl shape curve on the blank Now loosen the boss screws and remove the eccentric boss Undo and remove the machine screw and washer and remove the faceplate from eccentric boss Unscrew the wood screws and remove the bl...

Page 6: ...d re tighten the machine screw and washer Replace the eccentric boss back into the main body Set to position 35 in the sight window and re tighten the boss screws Now the line marking 2 will be in line with the reference mark on the chuck body Move the toolrest to the safe toolrest position at the face of the blank Switch on the lathe and mark a new centre No 2 Switch off the lathe and loosen the ...

Page 7: ...and Move the safe toolrest position at the outside of the wood Ensure the lathe is still set to a very low speed Switch on the lathe and watch the wood for a short while before starting to turn Once again care must be taken when turning off centre Approach the wood very carefully and allow for the fact that you will only touch a third of the wood on each rotation Take very small cuts with a 3 8 10...

Page 8: ...move the eccentric boss Undo and remove the machine screw washer and carefully remove the faceplate from the bi hexagonal locating socket and turn it through 120 degrees Replace it back into the socket and re tighten the machine screw and washer Replace the eccentric boss back into the main body and set to position 35 in the sight window and re tighten the boss screws Now the line marked 3 will be...

Page 9: ...en the screws Switch the lathe back on and turn the centre dish Then sand and finish as required Loosen the boss screws and remove the eccentric boss Undo the machine screw and washer and remove the faceplate from the eccentric boss Undo the woodscrews from the faceplate remove the bowl sand and finish the base We now have a 3 sided bowl with a cloverleaf design in the centre Robert Sorby Instruct...

Page 10: ...a standard 60 degree revolving live centre wind in the tailstock and lock to hold the wood in place Cabriole Candlestick Place the tool rest in the safe toolrest position Set the speed of the lathe appropriate for the size of wood and the capabilities of the lathe Switch the lathe on and turn the wood down to the round ensuring that only the minimum is removed Now place the tool rest to the safe t...

Page 11: ... turn a large V shape Switch off the lathe and check for a clean cut Now switch lathe back on and move along to the third mark and turn a large V shape Switch off the lathe and sand by hand to finish Holding the wood with one hand push back the tailstock so that it is clear Now very carefully remove the hexagonal stem from the socket and turn through 180 degrees Replace back into the socket at tha...

Page 12: ... a well as a parting cut and allow for the holding screws when parting the candlestick from the waste wood Do not part all the way through allow a small nib in the middle that can be removed with a fine saw Switch off the lathe and remove the candlestick from the waste then sand and finish as required Finish the piece with a suitable finish and proudly display your Carbriole Candlestick Robert Sor...

Page 13: ...e screw and washer Place the eccentric boss into the main body so that 0 is visible in the sight window Now tighten the boss screws and put tool rest in safe tool res position Adjust the lathe speed as appopriate and switch the lathe on Using the 3 8 bowl gouge turn the bowl blank down to the round Switch off the lathe and check for smooth finish Sand and finish Now place tool rest in safe tool re...

Page 14: ... used to mark the position of the groove It can be turned using the 3 8 fingenail gouge Switch off the lathe sand and finish Loosen the eccentric boss screws and remove the boss from the main body Undo the machine screw and washer and once very carefully index the hexagonal stem 1 position and replace into the hexagonal socket Re tighten the machine screw and washer and replace the boss back into ...

Page 15: ...ove the lid wCheck and sand Place the tool rest at the safe tool rest position Switch on the lathe and hollow out the inside of the box allowing rooms at the bottom for the holding screws and parting off The outer limit of the hollow will be the guide left from the inner lip when parted off Switch off lathe and offer the lid up to check for a good fit When the box has been hollowed sand and apply ...

Page 16: ...Instruction Data Sheet Page 16 NOTES Robert Sorby Instruction Data Sheet ECCENTRIC CHUCK PROJECTS ...

Page 17: ... the most versatile tools available The Multi Tip Hollowing Tool is fitted with a 3 4 19mm wide half round shank which makes it he most user friendly hollowing tool on the market It is supplied with three cutters One for under shoulder hollowing and one for straight box cutting The other cutter is tear drop shaped and is used for shear scraping The Robert Sorby thread cutting tools are available i...

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