Economy Sharpening On my beginners and sharpening and fettling courses I go into some detail on different sharpening media and techniques. However I think the bottom line for many leisure woodworkers is How can I get my tools really sharp at minimum cost. In this article I will suggest a system that should give a good edge with minimal outlay. I use a two bevel approach to sharpening. This means I have a wide coarsely ground bevel at 25⁰ and a narrower finely honed bevel at 30⁰ (1). Some have a single bevel at 30⁰ (2). I like the two bevel approach because the narrow honing bevel can be sharpened much more quickly than the wide single bevel, allowing you to get back to working the wood sooner. The problem with the two bevel approach is that one needs a system for grinding the 25⁰ bevel. 1. 2. Let s briefly look at the various media available for honing and grinding: Honing media. Wet and dry aluminium oxide paper on plate glass (14). This is the cheapest way of starting with sharpening. The wet and dry costs less than 1 a sheet and an off cut of plate glass (at least 10mm if poss.) can be picked up for less than 10. The paper is stuck to the glass using 3M Spray Mount. The spray mount may be the most expensive part (about 16 for 200ml on internet), however it is worth using as it gives smooth adhesion while other adhesives can be lumpy. Depending on grade wet and dry cuts well but wears out fairly quickly requiring regular replacement. Lapping film, produced by 3M, stuck to plate glass (alias Scary Sharp). The film is more expensive, about 2.80 from www.workshopheaven.co.uk, but as it s self adhesive you don t need the spray mount. Scary sharp cuts extraordinarily well and gives a fine edge, but is prone to tearing, particularly on the finer grades (note the tear in the 5 micron grit in the picture) (3).
3. 4. 5. Water stones. A set of three stones can be purchased for about 60. These stones cut well, producing a good edge very quickly. The down side is they wear, requiring flattening regularly, and they also should be stored in water so they can be a bit messy and take up space(4). Diamond and ceramic stones. These are fairly expensive, about 120 for a good quality double sided stone, they last a lifetime but beware of cheap imitations (5). Final honing is sometimes done on a leather strop to give a fine polished edge. The strop being dressed with an abrasive rouge. Grinding media. Grinding generally involves working the tool on a rotating wheel. A tool will be ground only occasionally while it will be honed frequently Dry grinding (6). Cheap, less than 50 for a grinding wheel. The best wheel is about 240 grit aluminium oxide. The main disadvantage is that the heat generated when grinding means there is a high likelihood of burning the edge of the tool, making the edge soft (7).
6. 7. 8. Whet stone grinding (8). The market leader in this is Tormek although there are other, cheaper, manufacturers. These machines are usually expensive. But there is no danger of burning and they have jigs to help hold the tool at the correct angle. Honing guides. Another element of sharpening is the method of holding the tool at the correct angle. There are various honing guides available, here s a selection of those I have used (9): Stanley honing guide (centre in picture). Simple guide, easy to use and cheap (about 10). Eclipse and other lookalikes (on left in picture). Simple, cheap (about 7), but doesn t hold the tool as positively as the Stanley Veritas (right in picture). Expensive (about 55), complicated, but it works very well once you have mastered it. I understand Rutland University are offering degrees in Veritas honing. There are many other honing guides but the above are those I have experience of. 9.
My recommended system. Having briefly surveyed what s available here s my recommended economy sharpening system. I would stick with the two bevel approach but use a Stanley honing guide with 80 grit wet and dry on plate glass to grind the primary bevel. I would use 600, 800 and 1200 grit wet and dry to hone the secondary bevel. I would finally polish the edge using Autosol metal polish on MDF. 10. 11. 12. 13. To grind set the blade in the guide at 25⁰. I use a couple of wooden bars stuck to the sharpening board to aid positioning the blade in the guide one for 30⁰and one for 25⁰(13). Work the edge on the 80 grit lubricated with water, only press on the back stroke in case you dig in. The 80 grit cuts quite fast and the guide ensures an accurate bevel, the pictures show a damaged chisel before grinding (10), after 2 minutes (11) and after 4 minutes (12), note how the chips in the edge have been removed. If the 80 grit loses its power simply strip it off and apply another piece with Spray Mount. Work the edge until you have a complete bevel on the front and a burr on the back edge. Don t forget that grinding is done only occasionally when the edge is damaged or the honing bevel has become too wide. You can hone at 30⁰ either by hand or using the guide. If you previously ground the edge rub off any burr left on the back on the 600 grit. Then fit the tool in the guide, if you are using one, using the setting bar. Work the edge on the 600 grit pressing only on the back stroke until a new burr is produced, this could take only a couple of strokes. Then go on to successive grits 800 and 1200. Finally rub the bevel on the MDF with Autosol, again only pressing on the back stroke. Rub the back flat on the 1200 grit and the Autosol to remove the burr and polish it. You should now have a polished sharp edge capable of shaving the back of your hand!
You may wish to vary this, perhaps trying a finer grit for the final honing or using a leather strop instead of the MDF which will wear with time. The 3M lapping film is a little more expensive but does give a very good edge quickly. The Veritas honing guide has a setting to automatically create the secondary bevel which can be useful, but expensive! 14. The setup pictured (14) consists of a piece of 18mm moisture resistant MDF about 500 x 330mm with a piece of 10mm glass, about 250 x 400mm, stuck to it with double sided tape. On this are spray mounted pieces of 80, 600, 800 and 1200 wet and dry about 95 x 230mm. To one side is an area of autosol with above the setting bars for 25⁰and 30⁰. The approximate costs for this: Glass 10 MDF 5 Abrasive 4 Spray Mount 16 Autosol 5 Total 40 The wet and dry will probably need replacing often and you will need to keep checking the stropping area top ensure it is flat as the mdf will wear, move to a new area when this happens. This system is a good cheap way to get into sharpening. After a while you will probably find that the many minor inconveniencies lead you to move on to a different system.