3 KEY FEATURES NECESSARY FOR SUCCESSFUL USE OF A SELF-CENTERING LATHE CHUCK

LATHE-CHUCK-3-JAWGRIP A good grip means a job can be completed safer and faster.

  • At least three jaw teeth should be engaged on the scroll at any position of the chuck jaws.
  • A ground finish on the scroll tooth gives good grip.
  • The RPM of the chuck affects the grip force exerted on the job. Maximum RPM is dependent on whether it is cast iron, SG iron or steel. Recommended safe RPM is governed by standards din6386.1 and VDI3106.
  • Chuck must be properly balanced or grip and RPM are adversely affected.

RUN-OUT ACCURACY This can vary with size of chuck.

  • For sizes up to 315mm diameter run-out accuracy should not exceed 40microns (.0001”)
  • A 400mm diameter chuck run-out accuracy can be up to 75 microns
  • For 500mm or 600mm diameter chucks run-out accuracy can be up to 100microns.

WEAR LIFE Correct material, accuracy of manufacture and finish of components determine life of the chuck.

  • A ground finish on the chuck body will extend wear life.
  • Surface of chuck should be blemish free.
  • Chucks should be cleaned and lubricated regularly with oil for jaws and grease for scroll and pinion.

Please visit www.robinsoninternational.com.au for all your engineering tools.

Radial Pole Chuck

Having a problem with your round magnetic chuck because the magnetic grip does not extend to the edge of the chuck?

Solve this problem with a RED-I-GRIP radial pole magnetic chuck. These chucks have a strong magnetic grip that extends to the edge of the chuck leaving no ‘dead’ areas as well as generating up to 16kg/ cm2 direct pull.
RED GRIP RADIAL POLE MAGNETIC CHUCKOther features to look for when selecting a magnetic chuck are
• A reliable ON/OFF switch system to ensure long life of the chuck as well as being able to be partially switched on whenever full grip is not needed.
• Chucks should always be sealed against coolant and di-electric fluid to ensure safety if working on EDM equipment.
• A chuck should have a strong grip to allow the grip diameter to be increased by using horizontal pole extensions and the use of vertical pole extensions should allow the chuck to be used on jobs without a flat grip surface.
• The radial pole chuck should also be able to be mounted on lathes, grinders and wherever extra powerful grip is needed

Also note that if a chuck has a centre hole it will allow non-magnetic plugs to be used to accurately centre jobs whereas a chuck without a centre hole can be machined after mounting to centre the hole to be concentric with the machine spindle axis.

source: www.robinsoninternational.com.au

NUMBER AND LETTER PUNCHES FOR METAL WORK

HIGH QUALITY, LOW COST NUMBER AND LETTER PUNCHES
Robinson International Pty Ltd supply professional quality number and letter punches.

• Made from S55C carbon steel correctly hardened and tempered to hardness HRC 58-62.
• Most are available with “tail end tempering”.
• Softer hit end means no chance of flying steel chips
• All punches are abrasive blast finish which ensures rust resistance.
• Packed in strong polypropylene boxes marked with size.
• These punches will keep on marking hit after hit!

The triangular support design of the marking face of these punches, coupled with expert production eliminates the possibility of the image cutting edge crushing or chipping when cutting hardened metals

The “R” photo demonstrates proper support for the cutting edge

CUTTING-EDGE

PUNCH SHOWING SUPPORT OF CUTTING EDGE

Available in:

STANDARD LETTER AND NUMBER SETS

NUMBER PUNCHES

NUMBER PUNCHES

REVERSED LETTER AND NUMBER SETS come in 2.5mm, 3mm, 5mm, 6mm & 8mm sizes for applications where reversed markings are required.
DOTTED LOW STRESS PUNCHES for use whenever reduced stress markings are required due to metal strength and fracture risk.

Sizes:

Letter sets
3mm and 6mm

Number sets
3mm, 4mm 5mm, 6mm and 8mm

DOTTED LOW STRESS NUMBER PUNCH

DOTTED LOW STRESS NUMBER PUNCH

TYPE HOLDER SETS

These can be used for marking metal and also date coding paper products for the packaging industry.

The set includes the type holder, a hexagonal wrench, 52 letters, (including 2 each A-Z), and 37

TYPE HOLDER SETS

Sizes available are 3mm, 5mm and 6mm.

Contact www.robinsoninternational.com.au

GAUGES

Various types of gauges are used for accurate measuring and testing.
CENTERING GAUGES are specially designed indicators for internal and external centering of jobs on machine tools.
• Can be used with machine spindle turning to allow speedy set up.
• Can be used vertically or horizontally
• Available with metric or inch reading

CENTERING GAUGE SET
CENTERING GAUGE SET

CENTRE GAUGES Available in Whitworth, UN or metric measurements.

Centre gauges are used in machining to check angles of tool bits used to cut screw threads.

CENTRE GAUGE

CENTRE GAUGE

RADIUS GAUGES come in various styles and are used to measure the radius of inner and outer surfaces of an object.

• Both external and internal radius on each leaf.

Inch radius sizes 1/32-17/64 and 9/32-33/64

Metric radius sizes 0.75mm-5mm and 5.5mm -13mm

• Separate leaves for external and internal radii.

Sizes: 1mm-7mm; 7.5mm-15mm;15.5mm-25mm

• Separate gauges for each radius.

Five measuring positions on each gauge.

Come in both metric and inch radii.

RADIUS GAUGE

RADIUS GAUGE

SCREW PITCH GAUGES

Used to measure the pitch of a thread on a screw or tapped hole.

Come in Imperial, UNF/UNC & Metric Combination gauges in Whitworth/Metric and AF/Metric BA and ACME both inch and metric.

SCREW PITCH GAUGE

SCREW PITCH GAUGE

SCREW CUTTING GAUGES

Used for checking tool angles when cutting threads.

• Comes in Whitworth, Metric, UN, BA and Acme threads

• Made from stainless steel

• Satin finish

SCREW CUTTTING GAUGE

SCREW CUTTTING GAUGE
SMALL HOLE GAUGE
4pce set 1/8″-1/2″ capacity
These are used to measure the diameter of a bore by inserting the gauge into the bore and adjusting till light pressure felt. The gauge is then measured with a caliper or micrometer.

SMALL HOLE GAUGE

SMALL HOLE GAUGE
MORSE TAPER GAUGES

Plug & Ring Gauges MT2, MT3, MT4, MT5

MORSE TAPER GAUGES

MORSE TAPER GAUGES
SURFACE ROUGHNESS GAUGES
• The surface roughness gauge set is a reliable and easy way for checking, identifying and specifying the degree of roughness of machined parts.
• The set contains thirty steel specimens of six machining methods: flat-lapping, reaming, grinding, horizontal milling, vertical milling and turning.
• Each specimen measures 7/8″ length x 3/8″ width and are calibrated in micro inch and micro meters.
• A chart giving metric and imperial equivalents for each surface roughness measurement is included in the set.

SURFACE ROUGHNESS GAUGES

SURFACE ROUGHNESS GAUGES

SURFACE GAUGES
• Fine ground steel base
• Fine adjustment screws
• Available 4″/7″ and 9″/12″
Used to measure the height of objects in metalwork. The pointer acts as a scriber for marking out work pieces.

SURFACE-GAUGES

SURFACE GAUGES

MICROMETER CHECK SET
The components that the set can check are length, flatness and parallelism of measuring faces. With the addition of optical flats the ¼ turn parallelism can also be checked.
• The 6425S MICROMETER CHECK SET can check the accuracy of micrometers from 0-25mm capacity up to 200mm capacity.

• It can also be used for checking vernier calipers to the same capacity.

• The set is based on the requirements of ISO3611-2010 (AS2102 amended) with the inclusion of 50, 75 and 100 mm gauges to allow larger capacity.

All sets are packed in secure, attractive protective cases.

MICROMETER CHECK SET

MICROMETER CHECK SET

GO/NOGO SCREW THREAD PLUG AND RING GAUGES

Used for checking, calibrating or setting of gauges.

SCREW THREAD GAUGES

• PLUG GAUGES from 1.6m to 355mm

• RING GAUGES from 2.00mm to 285mm

Available are gauges made to any tolerance grade in almost every thread type from any country or standard.

ALL GAUGES ARE SUPPLIED WITH TRACEABLE CERTIFICATES ACCEPTED UNDER ILAC AND MRA AGREEMENTS

• Gauge members are correctly heat treated and stabilised and have uniformly distributed carbides in a matrix of tempered martensite.

• Gauge members are size selected to maximum metal condition as this gives longer wear life.

• These features are only available from a maker with the highest precision measuring and calibration equipment and with independently assessed very small uncertainty of measurement.

PLAIN PLUG GAUGES
These are available in steel or with tungsten carbide Go member in sizes starting from 0.5mm upwards.

GO-NO GO SCREW THREAD GAUGES

GO/NO GO SCREW THREAD GAUGES

AEROCUT BROACH ARTICLE

Broaching is a machining process that uses a toothed tool, a broach, to remove material.

AEROCUT KEYWAY broaches quickly, easily and economically produce keyways in any sort of job.

An important feature of AEROCUT broaches is they are TiN coated at no extra cost.

Titanium Nitride (TiN) is applied as a thin coating to harden and protect cutting surfaces.

AEROCUT push-type KEYWAY broaches come in imperial and metric sizes and are supplied complete with shims.

Imperial (inch) sizes range from 1/16” up to 1”

Metric sizes range from 2mm up to 25mm

AEROCUT BROACH AND SHIMS

AEROCUT BROACH AND SHIMS

Collared or plain bushes are available for all bore sizes.

SQUARE BROACHES

Imperial (inch) sizes range from 1/8” to 1”

Metric sizes range from 4mm to 25mm

HEXAGONAL BROACHES

Imperial (inch) sizes from 1/8” to 1”

Metric sizes from 4mm to 25mm

KEYWAY BROACH SETS contain the most common keyway metric or imperial (inch) broaches and a range of bushes packed in varnished wooden boxes.

BROACH SET

BROACH SET

HOW TO CHOOSE A SELF-CENTERING LATHE CHUCK

A GOOD QUALITY CHUCK CAN ENSURE THAT ALL LATHES WILL PERFORM BETTER.

The main requirements for a lathe chuck is to securely and safely hold the job in the lathe, be accurate and maintain accuracy over a long time.

Understanding the difference between ultimate cost and immediate price is an important factor in selecting a lathe chuck. A lathe chuck should be selected according to the quality of the important features of GRIP; ACCURACY and WEAR LIFE. High quality of these feature means that the chuck will outlast a low price but low quality chuck many times over meaning much lower ultimate cost.

GRIP The better the grip, the safer is the work environment and the faster the job can be done.

Several factors affect the grip:

  • For self/centering chucks the percentage engagement between the scroll and the jaw teeth
  • There should be a minimum of 3 jaw teeth engaged on the scroll at any position of the jaws.

SMALL-DIAMETER-CHUCK
Figure 1 SMALL DIAMETER CHUCK SHOWING PITCHES OF EXPOSED SCROLL TOOTH

  • The smoothness of finish on the scroll tooth and the jaw teeth can affect the transmission of force. Ground finish is usually much smoother and more accurate than machined finish.
  • The grip faces of the jaws have to be properly designed and accurately made for the intended application.
  • The RPM of the chuck dramatically affects the grip force exerted on the job. The body material also determines the maximum safe RPM the chuck can turn. Choices are cast iron, SG iron and steel. The recommended safe RPM for lathe chucks is governed by Standards din 6386.1 and VDI3106. Note as a chuck wears or is not correctly maintained, the maximum recommended grip and RPM lessen.
  • A lathe chuck must be properly balanced or the grip and RPM is adversely affected.
  • Examine the end float of the jaws against the scroll tooth.

ACCURACY

Consider the accuracy the maker claims. Not all chucks have the same run-out accuracy when being operated. Some makes of chucks offer different accuracies for job run-out. A good quality chuck should have a run-out not exceeding 40 microns (0.001”) at any position on the scroll for sizes up to and including 315mm diameter. For 400mm diameter chucks a run-out of .075 microns is permissible. For 500mm or 600mm diameter chucks run-out of 0.10 microns is permissible. If the claimed run-out accuracy is MORE than these values then it is not a precision chuck.

WEAR LIFE & FINISH

The finish of a chuck will give a good indication of the quality. Look for “ground” finish on the chuck body and a blemish-free surface. The life of a chuck is determined by the selection of correct materials, accuracy of manufacture and finish of the various components and how these components work together. Lathe chucks should be regularly cleaned and re-lubricated using grease for the scroll and pinion and oil for the scroll and jaws. NEVER use graphite or graphite-based grease to lubricate a precision chuck, scroll and pinions.

SUMMARY

The following should be checked when selecting a lathe chuck

  • The overall finish and how the components work together
  • The end float of the jaws
  • The exposed Scroll (wind out the jaws) to ensure MINIMUM 3 jaw teeth can be engaged at any one time.
  • The percentage engagement between the scroll tooth and jaw teeth

JAW-IN-CHUCK-BODY

Figure 2 END VIEW OF JAW IN CHUCK BODY SHOWING REAR JAW TOOTH AND START OF SCROLL TOOTH

  • For up to 315mm size chuck check if the scroll is hardened and ground.
  • Does the maker’s catalogue list the materials used in the various components and the HRC of these components?
  • Is the chuck balanced?
  • Do the grip faces of the jaw appear to be uniformly made?
  • Consider the required RPM in order to select the body material.
  • Are spare parts available?
  • Does the maker specify accuracy?

 

 

 

ROBINSON INTERNATIONAL PTY LTD

www.robinsoninternational.com.au