Angles and cutting edge shapes

Bevel angle

The bevel angle is the angle between the bevel and the axis of the tool. The angle of the bevel has a number of effects. It defines the tool "edge angle' (except on chisels, which are sharpened on both sides so it is the sum of the bevel angles). It is also the cutting angle on gouges when the bevel is in contact v/ith the wood. The bevel angle determines the strength of the edge - larger angles have stronger edges. A 45' bevel is a good strong edge. Anything less than 30s and the edge is a bit fragile for turning but can be used for a special situation.

The bevel angle also defines the position of the handle relative to the direction of cut. A fine angle brings the handle close in line with the cut: a large angle brings the handle further away from the line of cut.

When gouges and chisels have long bevels. I would recommend putting on a secondary bevel to improve the tool control.

Matt surface for secure grip

Wood - ash or similar

Narrow section and grip for holding and rolling the tool in the lingers

Widening section for poftci grip

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Effccts of bevol angles

60"

Negative Rake Scraper

Finish positio:

Start position

30"

Change of handle position * th change of be.el angle

Finish positio:

Start position

Woodturning Chisel Angles
Too* swing - bevel angle

Bevel angle

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Woodturning Chisel Angles

Profile angle

The profile angle is the angle between the bevel and the cutting edge. In simple terms it defines the narrowest vee the tool will cut.

Rake angle

Standard scrapers are flat on top, which is a zero rake angle. Adding a negative rake at the cutting edge may reduce the risk of a dig-in.

Shape That Has Edge
Effect of profile angle

Rake angle

Negative rake grind scraper

Negative rake grind scraper

Zero rako grind icrapcr

Zero rako grind icrapcr

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Skew angle

A skew chisel of skew scraper is one where the cutting edge is not at 90" to the tool axis. The skew angle is measured from the cutting edge to the tool axis. The main effect of having a cutting edge skewed is to change the position of the handle relative to the cutting edge. This can greatly improve tccl control and allow access into tight spaces A good skew angle for a chisel would be 60'.

Effects of skew angle on tool handle position

Straight edge

Curved edge

Skewed scraper

Chisel skew angle

Chisel skew angle

Scraper skew 3nglo

Woodturning Chisel Angles

Square chisci

60® skew chisel

Change of handle position with the change of skew angle

60® skew chisel

Change of handle position with the change of skew angle

Square chisci

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Fingernail grind on the shallow fluted gouge (SFG)

Swept back grind on the deep fluted gouge (DFG}

Cutting edge shapes

Cutting edge shapes are very much visual definitions. The fingernail was at one time referred to as the 'lady fingernail". The bevel is not visible from the front of the tool. The fingernail grind is traditional and has been in use for a long time on shallow-fluted gouges. It is a fine detail grind, used for fine detail work.

The swept back grind is used on the deep-fluted gouge, where the edge is swept much further down the stock than the square grind. Some of the bevel will be visible from the front, though the sliape of the edge will be similar to that of the fingernail grind. This grind was developed in the early 1980s when HSS round stock came into woodturning. It is sometimes known as a 'Celtic' grind.

The square grind is where the gouge is just rolled on the platform, creating a square shape as if it had been sharpened with a pencil sharpener. It is typically used on the spindle roughing gouge.

On scrapers and chisels, the cutting edge shape is independent of the bevel and profile angles and any shape of cutting edge can t>e created on the grinder.

Some scrapers are form tools; that is. the shape of the cutting edge is similar or exactly the same as the shape it Is cutting. There are bead, cove and vee-cutting tools. These shapes are sharpened on the top of the tool so as not to change the cutting edge shape.

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Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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Responses

  • herugar
    What is the angles of cutting edge?
    3 years ago
  • furuta yemane
    What is the angle of cutting edge of a chizil?
    11 months ago

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