Röhm RN 398 lathe tools

RN-398   lathe tools
When workpieces are machined on a lathe, safety largely depends on the proper use and handling of the chuckíng tool.
The safe use of manually operated lathe chucks and 4 jaw independent chucks requires compliance with the following instructions.
1. The specifications and recommendations contained in the operating instructions must be strictly obsenıed.
2. After mounting on the lathe, the chuck or 4 jaw independent chuck must be checked for proper functioning before it is put into operatíon.
3. The maximum speed may only be used with the maximum torque applied at the wrench and provided that the chuckíng tool ís functíoning properly.
4. If the maximum speed of the lathe is higher than that of the chucking tool, then the machine must be equipped with a speed limitíng device.
5. The realibility of the chucking tool can be guaranteed if the maintenance instructions included in the operating instructions are stríctly observed. In this connection, the following instructions are particularly important:
5.1 Be sure to use the lubricant recommended in the operating instructions. (Unsuitable lubrícants may reduce the gripping force by more than 50%).
5.2 The lubrícant should reach all surfaces requiring
lubrication. (The close fits of the components call for high injection pressures. For this reason, a highpressure grease gun must be used at all grease nipples).
6. The gríppíng force should be checked with a load cell at regular intervals. "Regular checking is the only way of assuríng optimum safety".
7. If specíal tools are used, observe the following rules:
7.1 The jaws should be as líght and as low as possible.
The gripping point should be located as near as possible to the front of the chuckíng too1. Gripping points located at a major dístance from the front of
the tool cause higher surface pressure in the jaw ways and may substantially reduce the gripping force).
7.2 For desígn reasons, specíal jaws may be wider and/or higher than the stepped jaws normally used with the chuckíng tool. In that case, the resultant higher centrifugal forces must be taken into account in determíníng the gríppíng force required and the
recommended speed.
Mountíng the chuck on the machíne spindle nose
1.1 With lathe spíndle to DIN 800, usíng an adapter plate
Machine face contact, centering and thread (easy-action thread), mark hole
circle (Fig. 1). Drill through-holes (1 mm larger than screw diameter),
deburr. 1f cylinder-head screws are to be inserted, aп additional hole (for a
bolt) must be provided on the circumference to permit removal to the chuck
(Fig. 5.1).
1.1.2 Finish-machine adapter plate after screwing it onto the proposed
machine. Observe undercut (Fig. 2). Permissible axial slip (A): 0.003 mm, radial runout (B): max. 0.005 mm
S: centring depth of chuck - 0.5 mm

1.1.3 Mountíng the chuck on the adapter plate
The chuck must be abl,e to be fitted by hand, aided by a rubber-headed hammer (to tap the front with evenly distributed light blows). If necessary, remachine the centering
shoulder on the adapter plate.
Alternately tighten the mounting screws to an even torque.
The screws should not exert any force on the wall of the holes as this might twist the chuck body, lock the jaws and cause eccentricíty.
No machíníng of chuck!
1.2 Mountíng the chuck on a spindle wíth short taper nose
1.2.1 Carefully clean taper seat and contact surface of chuck and the machine spindle. Check spindle nose for radial runout and axial slip (0.005 mm permitted by DIN 6386 and
1S0 3089).
1.2.2 Mount chuck on machine spindle and lightly tighten the fastening elements.
1.2.3 Check gap by means of a feeler gauge.
Checkíng the gap after ínítal tíghtening:
a) Chucks mounted with studs to
DIN 55027 and 55022 or
Camlock studs to D1N 55029 and ASAB5.9D1
(not shown)
b) Front-mounted chucks held on the outer bolt circle to
D1N 55026, 55021,
ASA B 5.9 A1/A2
c) Front-mounted chucks held on the inner bolt circle to
D1N 55026, ASA B 5.9 A1/B1
0,02-0,05 mm
spindle nose 0.02-0,05 mm
Spindle nose
Spindle nose
1-3 mm
-3 mm
0-0,05 mm
1.2.4 Firmly tighten the fastening elements to aп even torque in diagonally opposite pairs.
Both the short taper and the face of the chuck must be in full contact wíth the spíndle nose after mountíng.
1.3 Mountíng the lathe chuck on a lathe spindle wíth long taper nose
Before mounting the chuck, carefully clean taper hole, screw thread and spindle nose. The taper must have a snug fit without wobble. Note the key. Tìghten the union nut.

Testing for Concentrícity and Face Play accordíng
to DIN 6386 Part 1*
Values given aгe based on the condition that machine spindle is in perfect order and chuck expertly mounted.
Measurements should be made only with hardened and perfectly cylindrical ground gauge plugs and thick-walled rings (to avoid distortion).

If the chuck does not conform to the specified concentricity tolerances, taper dimensions at machine spindle must be checked. Diameter and taper of short resp. long taper
must be checked, as must the concentricity of taper and face play, whilst face contact must be checked for faults in the case of short taper.
3. Care and treatment of the chuck
3.1 Lubrícation: Approx every 40 hours of operation through
greasing nipples on the front side of the chuck.
3.2 Partial cleaning: Clean jaws and jaw guides every 100 hours of operation approximately, leaving the chuck on the machine. Wipe jaws clean (no compressed air!), then back
them out and throughly clean them in petroleum or petroleum ether. Finally, coat jaws with fresh grease (F 80).
Reinsert jaws in the correct sequence!
3.3 Full cleaning
3.3.1 Approx. every 500 hours of operation, depending on the
conditions of use, remove the chuck from the machine, back out the jaws and disassemble the chuck.
3.3.2 See page 8 for disassembly. (Be sure to observe the proper sequence).
3.3.3 Thoroughly clean all parts in petroleum or petrouleum ether. Visually inspect the individual parts.
Then coat all parts with fresh grease. We recommend our „F 80" special grease, which is available in tins.
This special grease is not flung off even at high chuck speeds. „F 80" also resists high surface pressures and maintains the gripping force of the chuck.
3.3 To assemble the chuck, reverse the disassembling procedure. lnsert jaws in the order 1-2-3-4. The jaw numbers must agree with the numbers of the jaw guide slots in the
chuck body.
4. Spare parts (replacement)
Generally, all parts of the lathe chuck can be replaced without any need for remachining. It is, however, advisable to check first if the overall condition of the chuck still
warrants the replacement.
On request jaws of special design can be supplied.
Soft jaws which have been turned out once should not be unscrewed from the base jaw since concentricity will be lost.
Soft jaws: For accurate work, for special workpiece shapes and for recurrent workpiece diameters we strongly recommend the use of soft blank top jaws. They are both cheap and practical.
Heat treatment for soft jaws for materíal 16Mn Cr5
Note: The soft top jaws and block jaws have already been machined in soft state to fit into the chuck.
Any distortion through hardening should be corrected by grinding.
The slight backlash in the thread which can occasionally be noticed does not impair the quality of the chuck, as the jaws are always pressed firmly against the bearing surface in cucking.
Chíp guard
Guarantee
All our chucks are guaranteed against defects in material or workmanship for a period of 6 months and will be replaced free of charge if claims are found to be justífied.