Operation Representation

Tools/aids

Remarks

cleaning of the saw blade

petroleum, thinner

setting of the saw blades

setting pliers, set gauge, setting dial gauge

Use setting pliers. Because of its greater accuracy the setting dial gauge is more suitable than the set gauge for checking the setting width.

clamping of the circular saw blade into the sharpening machine

sharpening machine

Saw blade bore hole must fit exactly on the centring taper; put grinding wheel head into highest position, set tooth height greater than necessary.

setting of the saw blade thickness

1 saw blade, 2 adjustable stop, 3 sharpening wheel

sharpening machine

Middle of the saw blade exactly under the middle of the axis of the abrasive tool.

setting of the rake angle

sharpening machine

In case of band saw blades set according to the scale of rake angles of the sharpening machine - choose it a little greater at first.

setting of the saw pitch

1 feed finger, 2 path of the feed finger, 3 upper third of the saw tooth

sharpening machine, measuring tape

Measure the pitch at the saw blade and set it on the saw pitch scale of the machine.

fine setting of the tooth feed

1 sharpening wheel, 2 feed finger

sharpening machine

Switch on the machine, set the tooth feed so that the abrasive tool coming down slightly attacks the cutting face.

setting of the moment of shear

sharpening machine

The feed must start to act at the moment when the abrasive tool reaches the tooth gullet.

sharpening

sharpening machine, hone

At least 4 sharpening passes are necessary; material removed per pass 0.05...0.1 mm; in the last pass only minimum metal removal (0.01... 0.03 mm); carefully remove the sharpening burr with a fine hone.

setting of the tooth height

1 sharpening wheel, 2 flank of the saw tooth

sharpening machine

Fine setting:
Abrasive tool must run parallel to the flank.

checking of the top line

glass plate or tooth crest dial gauge

Check band saw blades like hand saws (see par. 10.1.), check circular saw blades with tooth crest dial gauge.

checking of cutting edge angles

1 rake angle gauge, 2 wedge angle gauge

bevel steel square, plate template, wedge angle gauge or similar

Check either with plate template as is done in the case of hand saws or with wedge or rake angle gauge or with bevel steel square.

Sharpening mistake

Cause of mistake

Effect of mistake

Elimination of mistake

uneven flank

feed is acting too early (flank becomes hollow) or too late (flank will get lugs)

chip diasposal rendered more difficult, warming-up and drifting of the saw blades

Set the moment of shear correctly.

tooth gullet radius too great

saw pitch set to small

low stability of the saw teeth, drifting of the saw blade

Increase the travel of the feed pawl.

tooth gullet radius too small

profile of the sharpening wheel rounded too little, wheel too thin

drifting of the saw blade at higher feed

Choose proper sharpening wheel, reduce the travel of the feed pawl.

tooth height too great or too small

machine wrongly set

changed tool geometry, shorter cutting life of the cutting edge, drifting of the saw blade

Correct the fine setting of the tooth height.

tooth height not uniform

axis of the sharpening wheel not exactly above the middle of the saw blade

load on the saw teeth not uniform, quicker dulling, worse cutting quality

Check the guidance of the saw blade and correct it.

discolouration of teeth crests

too much material removed by grinding or peripheral speed of the sharpening wheel too high or sharpening wheel too hard

loss of strength of the teeth crests, quicker dulling, drifting of the saw blade

Correct the sharpening wheel’s action and the tooth feed, choose another sharpening wheel.

saw pitch not uniform

tooth feed wrongly set, the sharpening wheel coming down too late attacks the cutting face too heavily

load on the saw teeth not uniform, drifting of the saw blade, worse cutting quality

Reset the sharpening wheel action on the cutting face.

wedge angle altered

tooth height setting too great (wedge angle becomes smaller) or too small (wedge angle becomes greater)

altered tool geometry, worse cutting conditions, higher load on the saw teeth

Correct the fine setting of the tooth height setting.

remaining of a sharpening burr

great abrasion, dull or excessively coarse-grained sharpening wheel

quicker dulling of the cutting edges

Make last sharpening pass with only little abrasion.

Operation
Representation

Tools/aids

Remarks

cleaning of the stripe iron and the clamping surface

solution

Cleaning also serves for preventing grinding inaccuracies.

clamping of stripe irons for sharpening

1 stripe iron, 2 clamping plate, 3 detent of stripe iron

sharpening machine

Clamp the stripe irons on the grinding beam so that the cutting edges project about 2 mm beyond the grinding beam and the sharpening wheel can run a few centimetres beyond the end of the stripe iron. When clamping is made in a vice, clamp from the middle of the stripe iron outwards.

infeed grinding

sharpening machine

Infeed the sharpening wheel according to the desired degree of keenness by 0.01...0.03 mm each.

abrasive machining

sharpening machine

Grind in one pass; infeed according to the degree of dulling 0.1...0.4 mm.

flat grinding

sharpening machine

Cup wheel is without tilt angle.

finish grinding

sharpening machine

Grind with moderate pressure. In the last pass the sharpening wheel must come clear. Always grind against the land.

hollow grinding

(1) view in the running direction of the cup wheel
(2) view at right angles to the running direction of the cup wheel
1 stripe iron, 2 cup wheel, 3 tilt angle

sharpening machine

Tilt the cup wheel by 2...3º in the running direction of the grinding wheel head; multiple honing is possible.

honing

1 machine iron, 2 hone with rough and fine sides

sharpening machine

Remove the grinding burr and fine traces of grinding. Hone only at the cutting face and always in longitudinal direction of the cutting edge. Hone must firmly be placed in position.

Operation
Representation

Tools/aids

Remarks

mounting of the cutter on the grinding arbor; centring

sharpening machine

Centring is made by means of centring rings.

aligning of the cutting edges for sharpening

sharpening machine

Align always according to the shortest cutting edge which is determined by means of the dial gauge.

grinding of the tool face

1 milling cutter, 2 sharpening wheel

sharpening machine

Grind relief-turned cutters only at the tool face.
Regrind cutters with straight flank (straight relief grind) at the tool face only slightly (infeed axially).

radial infeeding

1 sharpening wheel, 2 material removed in grinding, 3 infeed, 4 milling cutter

sharpening machine

Relief-turned cutters must be fed to the sharpening wheel radially, i.e. they must be turned around the axis during feeding.

checking of the cutting rake

sharpening machine, protractor

In order to ensure always the same cutting rake, the chip removal over the whole tool face is not uniform (chip removal increasing towards the periphery).

grinding of the flank

sharpening machine

Sharpen cutters with straight flank (see par. 9.4.) at the tool face and flank (with the exception of grooving and tonguing cutters which are sharpened only at the tool face).

axial infeeding

1 milling cutter, 2 sharpening wheel, 3 infeed

sharpening machine

Sharpen cutters with straight flank mainly at the flank, in-feed axially.

sharpening

sharpening machine

Grind all cutting edges uniformly.

dressing of the sharpening wheel

sharpening machine, silicon carbide stone

In case of considerable dulling of the cutting edges dress the sharpening wheel once more before finish grinding. To do this, hold the silicon carbide stone by freehand at an angle of 10...15° against the rotating sharpening wheel.

finish grinding

sharpening machine

In the final pass feed the sharpening wheel only slightly so that the sharpening burr can easily be removed.

removing of the sharpening burr

sharpening machine, hone

Carefully hone the cutting edges to remove the sharpening burr.

checking for true running

sharpening machine dial gauge

All cutting edges must lie on the same cutting circle (run-out £ 0.02 mm).

regrinding

sharpening machine

Regrind projecting cutting edges individually to lie on the cutting circle.