Technical Information · issue 20 of 2001
3/8" Oilomatic Picco Micro 1 Saw Chain: Cutters; G
IssueTI 20/2001
Full text
Page 1 of 2
Technical Information
20.2001
STIHL 3/8" Oilomatic Picco Micro 1 Saw Chain – Type 3998
Contents
1. Cutters
2. Triple-humped tie strap
3. Drive Links, Oilomatic Oil Reservoir
4. Service Note
5. Summary
The geometry of the chain links has been revised
and provides the following improvements over type
3900:
. longer wear life
. higher cutting performance
The shaded areas in the following illustrations show
the new profile.
1. Cutters
. 2 mm longer top plate (D) for a longer wear life.
. Larger sliding face on bottom (E) for improved
wear resistance.
2. Triple-humped tie strap
Compared to type 3900, the new cutters are higher
(A) and have
. a steeper top plate rake angle (B) for a higher
cutting performance
. a shorter depth gauge (C) for better
performance.
The profile of the triple-humped tie strap (F) has
been matched to the modified profile of the depth
gauge (shorter and higher).
TI_20_2001_02_01_01.fm english / USA
)m~ge 2 Technical Information 20.2001
3. Drive Links, Oilomatic Oil Reservoir 4. Service Note
Previous (3876, 3900) and new (3997, 3998) chain
links must not be mixed together. Although mixing is
physically possible, it may result in erratic running
behavior or problems. WARNING! The wrong
combination of cutters and guard links may result in
an increased risk of kickback.
With the exception of the triple-humped tie strap, all
parts of the chain are exactly the same as those of
type 3997 (PM).
The drive links are no longer "necked" (G). The
benefits are:
. Improved durability
. Fatigue strength increased
Drive links feature an additional Oilomatic oil
reservoir (H) for
. improved chain lubrication
. reduced cutting attachment wear
The STIHL Oilomatic chain lubricating system with
the additional oil reservoir is described in detail in
TI 39.96.
5. Summary
Item Part Name Previous New Remarks
1 Right-hand cutter 3876 662 0400 3997 662 0400 1)
2 Left-hand cutter 3876 662 0600 3997 662 0600 1)
3 Drive link 3876 662 1000 3997 662 1000 1)
4 Preset tie strap 3876 660 6600 3997 660 6600 1)
5 Right-hand tie strap (without rivet) 3900 662 3900 3998 662 3900 1)
6 Left-hand tie strap (without rivet) 3900 662 4000 3998 662 4000 1)
Modification to be introduced: in progress
Remarks
1) Previous version of part remains available for chain type 3900
Last Technical Information on STIHL saw chain: 28.2000
© 2001 Andreas Stihl AG & Co. Technical Documentation
Waiblingen D1/MTK 7197
TI_20_2001_02_01_01.fm Page 2 of 2
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