Beetling of Teeth and Equalizing Beetled Teeth

Beetling of Teeth

Beetled saw blade is a better tool than the same set saw blade.

Prerequisites for Proper Beetling

  • The material of the blade must be designated for beetling
  • The sharpening shop must be equipped with beetling and equalizing machines, in order to secure the necessary accuracy and productivity during the preparation of the tool
  • It is necessary to pay attention to the maintenance of the sharpeners
  • It is suitable to use the beetled tools for barked wood, because it is not possible to repair the damage to the beetle by additional blade setting that are clamped in the frame

Before Beetling

Before beginning the beetling it is necessary to carefully remove possible deviations of teeth to the side, so that bending out of the teeth would not occur during beetling or beetling to one side. If needed then we modify the inner tension of the blade before beetling.

A new tool must be re-sharpened before beetling! In order to reach the correct beetle it is necessary that all of the teeth have the same span, height (in the tolerance of ±0.2 mm), cutting angles and that the surface of the face and the back is perpendicular to the side area of the saw blade.

During Beetling

Before the beetling it is necessary to coat the teeth (face) with grease chock, diesel, or with a special product that is designated for beetling. Oil is unsuitable, it dirties the grinding disk during sharpening.

Generally the beetling is performed with a beetling roller with an eccentric cross section, during its turning the tooth point is beetled; meanwhile the back is rested against the anvil, the position of its axis is constant with regards to the axis of the beetling roller.

Generally it is possible to set the beetling machine for 2 basic types of beetling - long beetle and short. The long beetle enables a higher number of sharpenings, but it causes a greater friction of the teeth in the groove. The short beetle on the other hand has a lower friction, but it does not withstand as many sharpenings.

Recommended values for RP beetling
Wood Setting to one side
Soft - humidity up to 25% 0.55 mm - 0.65 mm
Soft - humidity above 25% 0.65 mm - 0.75 mm
Soft - frozen 0.55 mm - 0.65 mm
Hard - humidity up to 25% 0.45 mm - 0.50 mm
Hard - humidity above 25% 0.55 mm - 0.60 mm
Hard - frozen 0.45 mm - 0.50 mm

Equalizing of Beetled Teeth

The purpose of equalizing is to create cutting edges of the same widths and of the same size of angles of beetled teeth from the cut edge towards the direction of the base of the tooth and at the same time towards the direction of the back edge of the tooth, so that the friction over the side areas was limited.

Before equalizing it is recommended to remove (using the file or grinding) find tips which resulted from beetling, they could cause a nonuniform width of equalized teeth.

The equalizing is done in two methods:

  • By the side pressure of the jaws of the equalizer (lasts longer, it is also possible to use the manual equalizing device)
  • Grinding with writing discs

Defects During Beetling, Their Consequences and Repairs:

Defect Cause Consequence Repair
One sided beetling
  1. in the width of the beetle
  2. in the height of the beetle
Eskew ground face, back of the tooth; bending out of the tooth before beetling, eccentric wear, wear of the anvil, faulty grinding of the anvil's seating area; the beetling roller is not perpendicular to the area of the blade; a lesser hardness on one side of the blade; needle after sharpening Uneven width and height of areas on the sides after equalizing; usually one-sided beetle even after equalizing; lower number of grindings, greater susceptibility to damage on the side of the small side area, on the one side the beetle is ground down sooner; saw blade run in Set the grinding disk precisely perpendicular to the area over the blade and above the middle of its thickness; re grind the blade; measure the blade before the beetling; replacement of the eccentric; grinding down of the anvil; use a template to inspect the perpendicularity
Bent tip of the tooth
  1. up
  2. down
Angle of the seating plates of the anvil is greater (smaller) than the angle of the back
  1. the tip of the tooth can break off; a danger of burning the tip during sharpening
  2. necessary to grind off a thicker layer of material on the back; unnecessary stressing of the tip's material
Adjustment of the guide of the beetling device either up or down; grinding down of the seating plates of the anvil according to the angle of the back
Small height and width of the beetle
The anvil is let down too far; in the default position the eccentric is already partially over turned in the upward direction It is necessary to beetle several times Move the anvil out higher, regrind
The beetle is too low
The anvil is too high, the tip of the tooth is not on the cutting edge (a small tooth face angle); faulty placement of the beetling device; impurities on the tooth face Over grinding of the tooth backs, greater consumption of saw blades Tap the anvil gently onto the cylindrical part of the roller, grind away the anvil, move the cutting edge of the anvil
Widening of the beetle the greatest at about the middle of the height of the beetle
The saw blade was not yet beetled Necessary to greatly grind down the back of the tooth Regrind and beetle again
Too deep of a beetling; unsuitable material of the saw blades; unsuitable cross section of the eccentric Breach and breaking off of parts of the edge, smaller feed speeds, blade run in, greater roughness of the surface Lower the eccentricity; adjust the default position of the eccentric; lower the transition in to the cylindrical part of the roller; coat the tooth face before beetling; set the saw blades and use them as blades with set teeth
Shallow beetle, small widening of the tip
Small eccentricity, small roller diameter; the eccentric in the default position is already somewhat turned; the tooth is beetled for the first time; slippage of the clamping device, impurities on the face of the tooth Necessary to beetle frequently Remove the causes, beetle that tooth 2x, possibly regrind and beetle again
Deep beetle, great widening of the tip
Great eccentricity Unnecessarily great shaping of material weariness during equalizing; possibility of cracks even with suitable steel Lowering of eccentricity; lower the anvil
The forming of a long thick needle
The anvil is too high, the metal is pushed in between the roller and the anvil Before equalizing it is necessary to manually remove the tips Tap the anvil onto the roller
Breaking off of the tooth tip
The cutting edge is moved too far in the direction to the tooth's back; great face angle for the given adjustment of the beetling device; the anvil is tapped onto the roller Looses by great grinding down of the back Grind down the bottom plate of the anvil and lower it, adjustment of the beetling device
Uneven widening of the tooth tips with regards to the area of the blade
Tooth bent to the side Blade run in; greater roughness of the surface, greater cutting groove Inspection of the teeth before beetling
Uneven widening of the tooth with regards to the tooth axis
The jaws of the equalizer did not seat down onto the area of the blade (impurities); uneven hardness of both of the areas of the blade, defective function of the jaws Blade run in Removal of the causes, inspection of the saw blade
Various sizes of side plate One sided beetling; defective function of the jaws On one side of the tooth the beetle is sooner ground down; blade run in See one sided beetling; inspection of the equalizer
Various widening of the teeth tips Uneven teeth height, the needle after beetling was not removed; defective seating down of the equalizer onto the blade Greater roughness of the sawn wood's surface; small feed speeds; run in Inspection of the cutting edge; removing the needle after the beetling proper seating down of the equalizer to the face of the tooth

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