|Forum topic by Benvolio||posted 08-19-2013 12:44 AM||3333 views||18 times favorited||42 replies|
08-19-2013 12:44 AM
I’ve been thinking for ages that there has to be a better way to do free-hand sharpening….
Honing guides give a very controlled operation and a predictable outcome when used to sharpen a bevel on chisels and straight plane irons…
But think it’s safe to say that most of us would prefer to have the skills to free-hand sharpen if we could. Free-handing is much much quicker, easier to camber the steel and there is no fiddly set up involved. It’s also a skill perfected by our wood working ancestors that I’m sure some of us are mildly embarassed to say we’re forgetting.
The mighty Paul Seller’s advice on free hand sharpening is to ``feel for 30 degrees``. Fantastic if you’ve spent the last 40 years knowing what that feels like, but maybe a struggle for the weekend wood worker.
Rob Cosman has helpfully made an angle trainer I’ve never used this, but looking at it, it looks like it’s more of a jig than a free hand method. It also has limitations that it can’t be used on a leather strop (which is how I achieve my final hone). Nor can it be used to produce the more resilient convexed bevel that we get with free handing.
So I came up with this little device to help rest the chisel at the desired angle.
A thirty degree block of wood. Rare earth magnets on one side and a spirit level on top.
The idea is fairly self explanitory but in case my diagram doesn’t explain it:
The block clicks onto the chisel or plane iron back with magnets. The steel to be sharpened is set at the correct bevel angle by the long ways motion of the spirit level bubble – when the bubble is centered, you know you’re honing a dead square 30 degree bevel.
When honing, a slight rock of the steel (as with normal free hand sharpening) will show some movement in the bubble which after a short acclimatisation period, should give the user a predictable convex bevel to the blade.
The spirit level works in two dimensions so by getting to know your level, you can rock side to side to make cambers on your jack, jointer and scrub plane irons.
I’m not inclined to call this a `jig` as such. To me, that word is too closely linked to devices that hold tools or work pieces in such a way as to irrevocably extirpate dexterity from the wood worker. This is more of an instrument – an indicator that feeds back to the wood worker information on what he or she is doing but still leaves them in absolute control of the operation – and let’s be honest, we all want to say we have those earthy fundimental woodworking skills!
Both the rare earth magnets and spirit level together ost me less than five pounds from ebay. The spirit level is sold as a ``Turntable level`` and is used to help DJs set up their electric grammarphones and only cost a couple of quid. 12mm x 6mm.
The magnets are just tiny 5mm ones CA glued into holes in the back of a scrap block of ash – which is then sanded flush to keep it all nice an accurate.
Here is mine in action. (On setting up one of Jusfine's chisels :-) )
The results of the guide were very good. Honed on 1000 and 4000 water stones then stropped on jewellers rouge. The chisel easily took the hair off my arm and well and truly passed the paper test.
All in all, this was super quick to make, cheaper than a conventional honing guide and gives you the benefits of free-hand sharpening with the certainty that you’re hitting the desired angles every time.
To me, my favourite thing about this though is how quick it makes sharpening. So long as you have your little block to hand it’s just `click` and you’re ready to go – no more scrabbling around for the big screw driver and faffing around with those set up blocks for the honing guide and hoping at the end of it all that your tip is square.
I don’t know whether I’m the first person to have this idea, but I haven’t seen it else where. If anyone has any opinions on this, I’ve love to hear what you have to say.
-- Ben, England.