How to select used woodcarving chisels and restore them to usable condition.

Summary

Describes how to select used woodcarving chisels, and to restore them to usable condition.  The author is a retired museum curator and now a professional furniture restorer/conservator who has worked for museums, National Trust collections and Churches.

1    Introduction

Most old woodcarving tools are bought by carvers to use and that is my aim.  For those not familiar with carving tools it is easy to pick up an old firmer gouge and mistake it for a carving gouge.  Carving tools, generally, are more elegant in shape, thinner in the blade and if not parallel, gently tapering along their length.  They do not have the shoulders of the Carpenters or Cabinet Makers gouges.

The basic profiles of carving tools are the flat chisel, the U-shaped gouge and the V or parting tool.  Given a range of sizes from say 2mm (1/16”) to 38mm (1½”) and numerous variations of curved gouges from almost flat to a deep U shape; then other variations in straight blade, curved, or spoon bent and back bent, the range of tools runs into several hundred.  Henry Taylor (Est.1834) still make a range of over 150 tools in Sheffield.  No carver would need the full complement of tools but would buy according to special needs of his style of work.  

British Carving Tools conform generally to the “Sheffield List” (a standard defining the different shapes and sizes of tool).  You may find that any Continental Tools do not, eg a Swiss Pfeil ¾” No. 5 gouge is not necessarily the same as a Henry Taylor ¾” No. 5.

See last page for Fig.1 - explanatory diagrams.

2    Old Carving Tools

The majority of tools found today will be from the second half of the 19th century and later.  Generally speaking, it is thought that earlier tools, ie from the 18th century and before will have been sharpened out of existence.  They are extremely rare.

Professional tools tend to be longer and more substantial than the “amateur”, “gentleman's” and “ladies'” tools of the last decades of the 19th and early 20th century when carving became a popular pastime.  These are sometimes in sets and often without bolsters abutting the handle.  Handles are often thin and would not last long using a mallet.

Makers of good quality tools to look out for are:-

ADDIS    Some of the best and still sought after for use.  (The Hawley Collection contains some excellent notes on the history of the Addis family of carving tool makers which dispels many of the errors written about the firm.)

HERRING BROS.     Some also stamped “Prize Medals.”  Also considered among the best and still sought after for use.  

WARD & PAYNE/ADDIS Some stamped “10 Prize Medals.”   

I & H SORBY

MOULSON BROS.

HILL, SHEFFIELD    Cannon Trade Mark

HENRY TAYLOR     Older tools with acorn Trade Mark.

ROBERT SORBY

WM. MARPLES & SONS.

There are many more but the above are all good to use.


3    Condition

Carving gouges are sharpened out-cannel ie the bevel is ground on the convex outside/underside of the curve.  Pitting on the concave inside of a gouge is terminal if it is deep into the metal as sharpening means the cutting edge develops nicks as it meets the pits.  Pitting on the bevel side is not so important as it can be ground away.  The same would apply to other profiles and particularly the V-tool.

Handles come in various shapes, timbers and patination.  I would endeavour to keep any original handle, any in ebony or rosewood, and any bearing owner name stamps, as long as they are not split and hazardous to use.  I always discard later handles that have any roughness or signs of splitting on the domed end as these cause a blister to the palm in a very short time.  I turn my own handles in a variety of woods which help identify each tool.  Whilst the idea of a matching set of handles is attractive, in practice professionals do the opposite ie individual handles allowing easy identification of the tool.


4    Restore to use

My first task is to reshape the business end and get rid of any pitting.  Removing internal pitting even if it is light is a challenge and needs patience.  With the variety of profiles in carving tools, I find a range of carborundum slip stones, plus scrap wood shapes (dowel is good) with wet and dry paper (fine grits) around them will do the job.  Try and keep away from the actual cutting edge or you will create an unwanted bevel on the inside.  Fine grinding heads in a Dremel can be used but I find it so easy to catch edges and create grind marks that I do not use them.  I strongly advise hand methods.

The next step involves resharpening and reshaping the bevel.  I use a very cheap Wickes grinder which has a slow running coarse grit wheel running in a water bath.  This removes any external pitting on the bevel and re-shapes the tool roughly.  Personally, I don’t worry too much about grinding angles but keep low and produce one (not a double bevel) long curving bevel, eliminating the ‘heel’ which is normally seen.  This allows the tool to enter the wood in a sweeping cut and gets ride of the lever or fulcrum effect of the heel.

The grinding of the bevel I do at 90° to the face of the wheel to avoid any hollow grinding effect.  I rotate the gouge around its profile just enough not to round off the corners.  This takes some practice, especially on deeper U shapes.  However, I do sharpen some gouges into a bull nose (like a fingernail) by rounding the corners off, as this shape can be useful in some carving situations.

Warning:  If you are using a normal grinder at high speed be very careful not to overheat the cutting edge.  I normally dip in water after each touch on the wheel.  Ashley Iles do sell a red rubberized wheel which is safer for regrinding at high speed but I still dip on each stroke.


5    The Oilstone

My next stage is using a medium and fine grit Norton or Carborundum flat stone.  I remove all the grinder marks made in shaping my final profile.  I use Turps Substitute or White Spirit on the stones.  To do this I sweep the bevel from side to side, holding it again at 90° to the stone as in grinding and rocking the tool from one corner to the other on each stroke.  I also raise and lower as I do this to cover the curved bevel from cutting edge to the shank.


6    Final Sharpening

To achieve a fine “surgical” cutting edge, I use a cotton polishing mop and green polishing compound.  Warning: The mop must be rotating away from the tool otherwise the tool will end up through your workshop roof or yourself!  Use a sweeping motion, with dipping in water to cool.  Do the outside of the gouge until it has a smooth shiny surface free from any grinding marks.  Do the same to the inside, holding it flat to the top of the mop.  Test the cutting edge on scrap wood.  Repeat the polishing both sides until it cuts easily and cleanly.  A joy!


7    Exceptions

The process I have described can be applied to any profile carving tool except those that have very tightly cranked curves.  One of the most difficult to sharpen is the V-tool which should be treated as two flat chisels and the intersection of the V as a tiny gouge.  Contrary to what all the books say, if the wings of the V are splayed back slightly from 90°, the tool cuts better and does not bury in the wood so readily.


8    Disaster – Keep your temper

In the grinding process, if the edge of a tool suddenly blues it means that the vital hard cutting edge is ruined.  I am sure the little Sheffield “mesters” in TATHS will throw their hands up in horror at the following, but I do make some carving tools which hold their cutting edge, so all is not lost.

Using a propane/butane blowlamp or blowtorch, make a small box-like enclosure with fire bricks.  Heat the blued chisel (2 or 3” will do) cherry red and plunge in cold water.  This will harden the piece.  Clean the blade with fine emery and wet and dry and buff with the cotton mop till shiny.  Using the blowlamp about midway on the blade, I use a stroking movement of the flame towards the cutting edge.  You have got to concentrate for as soon as there is the slightest change in colour, you need to be ready to plunge into water again.  The steel will first turn a very slightly “brassy”/pale straw colour and then quickly to light straw, then straw, then bronze (brown), peacock, purple, dark purple and blue.  It is light straw you are looking for, or straw will do; as soon as it appears plunge into the water.  Any further and your tool will be brittle at the edge and will chip in use.  If it doesn’t work first time do both processes again.


9    Some final points

For fine adjustments to the cutting edges of carving tools, I found the small pocket diamond hones sold under the name DARLAC most useful.  They are good for removing pits on flat areas.

Once carving tools are really sharp, I keep the edges keen with a few strokes on a strop.  This is a piece of thick, preferably untanned, leather skin (smooth) side up, glued to a piece of wood and dressed with SOLVOL AUTOSOL chrome polish.  Some leather glued to rounded dowels, does the inside curve of a gouge.  MDF also makes a strop but in both cases, the tool has to be drawn towards the operator on each stroke, ie the strop is pulled away from the edge.  A small collection of fine carborundum slip stones are useful for the insides of various profiles.  The polishing mop is used for a few seconds on each tool after a long carving session.

Now your tools are razor sharp, get a piece of Lime and listen to that wonderful zipping sound as you make your first chips!

Woodcarving Chisels
Ref No: TN 03.01
 
Date: 30-07-2013
 
Author: Alan Suddes
Suggestions for improvement are welcomed, please email: conservation@taths.org.uk
IMPORTANT: The advice in these notes is provided by members and others. It is given in good faith but neither the contributors nor the Society can endorse or guarantee the accuracy or safety of the information. The society does not recommend or guarantee any individual or organisation named.

Treatment techniques described may not be suitable for items of high or historical value. Users should always test first on a small inconspicuous area; observe safety and health guidelines given by suppliers, and dispose of used materials responsibly. The Society does not endorse or guarantee any proprietary products named (and it recognises that other products may be suitable). If in any doubt, expert advice should be obtained.

Add comment


Security code
Refresh