Rotabroach COMMANDO 40 - 10) REMEDIES FOR HOLE MAKING PROBLEMS

Issue 3 Original Version Sept 2020
- 10 -
10) REMEDIES FOR HOLE MAKING PROBLEMS
Problem
Cause
Remedy
1) Magnetic base
won’t hold
effectively
Material being cut may be too thin for efficient
holding.
Attach an additional piece of metal under work-piece where
magnet will be located, or mechanically clamp magnetic base
to work-piece.
Swarf or dirt under magnet.
Clean magnet.
Irregularity on magnet contact or work-piece.
Use extreme care; file any imperfections flush to surface.
Insufficient current going to magnet during drilling
cycles.
Confirm power supply and output from control unit, check
supply cable.
2) Cutter skips
out of centre-
punch mark at
initiation of cut
Magnetic base is not holding effectively.
See causes and remedies above.
Worn arbor bushing and/or ejector collar.
Replace! Only a few thousandths wear permissible. New arbor
bushing is needed.
Light pressure only is needed until a groove is cut. The groove
then serves as a stabiliser.
Too much feed pressure at start of cut.
Replace or re-sharpen. Sharpening service is available.
Cutter is dull, worn, chipped or incorrectly
sharpened.
Improve centre-punch and/or replace worn parts
Poor centre-punch mark; weak pilot spring; pilot not
centred in centre-punch mark.
Replace part or parts
Worn or bent pilot, worn pilot hole.
Replace part or parts
Loose bolts on motor bushing support bracket, main
casting or loose gib adjusting set screws.
Adjust where necessary
3) Excessive
drilling pressure
required
Incorrectly re-sharpened, worn or chipped cutter.
Re-sharpen or replace.
Coming down on swarf lying on surface of work-
piece.
Take care not to start a cut on swarf.
Gibs out of adjustment or lack of lubrication.
Adjust setscrews, and lubricate.
Swarf accumulated (packed) inside cutter.
Clear cutter.
4) Cutter
breakage
Steel swarf or dirt under cutter.
Remove cutter, clean part thoroughly and replace.
Incorrectly re-sharpened or worn cutter.
Always have a new cutter on hand to refer to for correct tooth
geometry, together with instruction sheet.
Cutter skipping.
See causes and remedies (2).
Gib Strip need adjustment.
Tighten Gib Strip.
Cutter not attached tightly to arbor.
Retighten.
Insufficient use of cutting oil or unsuitable type of oil.
Inject oil of light viscosity into the coolant-inducing ring and
check that oil is being metered into cutter when pilot is
depressed. If not, check pilot groove and arbor internally for
dirt or apply oil externally. (Even a small amount of oil is very
effective).
5) Excessive
cutter wear
See cause and remedy above
Incorrectly re-sharpened cutter.
Do not use. Refer to instructions and a new cutter for proper
tooth geometry.
Exercise, insufficient or spasmodic cutting pressure.
Use sufficient steady pressure to slow the drill down. This will
result in optimum cutting speed and chip load.