Freehand sharpening problems

[Tiger]

Dear all,

I have been freehand sharpening most of my turning chisels but occassionally I run into problems.

Sometimes I do not get the sparks over the edge (which tell me that I've hit the correct angle), sometimes it is difficult to see the sparks and there are times when I do get the sparks but I have to tilt the tool so far that it doesn't match the original bevel and I wind up with a secondary bevel.

Also, I notice on the Raffan video that some of his tools have a multifaceted bevel, this happens to me too but does not seem to hinder the cutting efficiency of the tool, I'm talking about very small extra bevels that sit on a fairly distinct main bevel. It is difficult for me to get an uniform bevel everytime I freehand, is it vital and do you guys just start again or continue working until the next re-grind? I am going to use a piece of angle iron as my tool rest, how wide should it be would an inch be ok or would you need more?

[CameronPotter]

Tool rest for grinding? Mine is about 1.5-2 inches wide - but it is wood.

As for mistakes in grinding, often I find that it doesn't make that big a difference. You may have trouble getting a lovely finish with the tool, but it will still cut (provide that you did actually regrind the edge rather than just the back of the bevel).

I tend to do a bit of plastic turning (in which the bevel doesn't rub anyway) and then regrind when it becomes blunt again.

Basically, I think that if it works for you, then don't worry. If you notice a big difference between a well ground chisel and a poorly ground one, then do worry. Mine are all good enough for my lathe work (but I did come from a knife making background - so metal grinding isn't exactly new to me).

Cam

[rsser]

A bowl gouge with two bevels can help you turn the corner at the bottom of the bowl wall, but otherwise isn't recommended.

In the longer term buying a gouge sharpening jig will save you the money lost in ground-away M2 HSS. Even just one of those Taiwanese $40 platform rests will allow you to reliably grind a straight bevel which is all you really need for bowls - and be used for scrapers as well.

[Tiger]

Ern, I actually have a platform jig but most of my tools have been shortened to the point that the jig is useless to rest on.

[rsser]

Oh, OK. Sorry.

My solution to that is to clamp a narrow strip of timber onto the platform edge closest to the wheel. Lifts the handle clear. But you may have tried this already.

[JDarvall]

I actually find tool rests, most of the time,to be a hinderence....though I'm not too crash hot at sharpening spindle gouges freehand.

The trick for me is to support the handle of the tool as well as possible up against your body.....and to keep the blade as vertical as possible so I can eyeball the very edge. So, I've gota have the grinder right on the edge of the table. No tool rest.

This may help.....I described how I do this here....
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=22108&page=6
If you go down the page and look at posts #83 and #84. Heaps of pictures etc. Might be something in there that could help you.

I think it just comes down to practise and being observent. Goodluck.

[Skew ChiDAMN!!]

I don't know anyone who freehands a perfect bevel every time. So long as the angle doesn't deviate too far and the main bevel accounts for some 80% of the face, I don't worry about it until the next grind.

As Ern said, a secondary bevel can be helpful in turning tight radii in bowls, but apart from that it's better to have a single bevel for a several of reasons... it's easier to maintain a bevel rub, there's more steel supporting the cutting edge hence less chance of chipping the edge and better heat dissipation.

The latter is particularly true for scrapers.

[Tiger]

Thanks, guys, I will give your suggestions a go. Apricot you need to make a video of using your body as a jig, it'll make good viewing:D .