First cut short:
For workpieces with a thread against the collar and short thread run out
Thread run out approximately 2 x lead.
First cut medium:
For workpieces without or little oversize, blank or preturned
Thread run out approximately 3 x lead.
First cut long:
For workpieces made of rolled material or with oversize.
Thread run out approximately 4-5 x lead.
Please note:
By means of a longer first cut you will receive a better surface of the threads
and a better lifetime.
Please pay attention when choosing the first cut that the cheek of the chasers won’t
touch the collar of the workpiece.
They run the risk to break
.
Labelling of the chasers:
On the cheek of the chaser the design of the chaser, the chaser lead and the number
of the chaser (1-4) within a set is engraved.
Examples for thread labelling on the chaser:
M 0, 7 P
Chaser for all metric ISO- threads according to DIN 13 with lead of 0, 7 mm
W 28 GG
Chasers for all Whitworth threads according to ISO 228 resp. B.S. 84 for threads
according to DIN 11 with lead of 28 movements per inch and all cylindrical Whit-
worth- pipe threads according to DIN 259 with lead of 28 movements per inch.
R 28 GG K 1:16
Chasers for all conical Whitworth pipe threads with taper 1:16 according to DIN
2999 and 3858 with lead of 28 movements per inch.
If the chasers are labelled with an additional manufacturing number (set number),
only chasers with the same numbering should be used in the set.
Chasers without set number are interchangeable among each other.
Figure 6:
Labelling of the chasers
Figure 5: Chaser first cuts
set number
chaser number
1- resp. 2-3-4
pitch
profile design
10
Operating Manual ZR 26-I
Chasers