Thread: Grinding Jigs and Camber

Jono - these will help you reach your goal of getting sharp tools in the near term. i think in the longer term for both purposes you may wish do everything freehand for speed.

We typically maintain camber with honing and grind only to remove metal behind the honed edge (without removing the edge) to make it easier to maintain shape.

The confounding issue doing this is getting initial camber that's suitable for a given plane, of course.

But the thinking process is admirable, and thinking and experimenting in the shop is always good when results can be observed as in your case (not so much so when results are hypothetical and attainment of goals is also on a hypothetical basis!!).

Jono, I echo David's comments.

The only blades I use a machine to grind to a camber are those with marked camber, such as a jack plane (about 11-12 inches) and a scrub plane (3"). Even so, the bevels need to be honed by hand. All smoothers are cambered and honed by hand.

Years ago, Tormek released a holder for cambering. I recall trying it (per David Charlesworth's recommendation), and gave up on it immediately. Nothing like hand control for fine tolerances.

Regards from Perth

Derek (still in New Zealand)

Hi David and Derek,

Thanks for your reply.

I have done some free hand grinding but need some practice. And do all my honing free hand.

What would be considered the best practice technique, for free hand grinding at the moment? I assume you rest the back of your fingers on the grinder rest, while holding the blade and concentrate.

And do you use the cambered blade to make square adjustments to the edge of a board? I am trying to do this effectively.

Hi, Jono - I will say this in all seriousness - for me, it doesn't matter that much. Sometimes I grind with a tool rest set to an angle, and sometimes I leave the tool rest square. When the latter, I use my finger across the back of a plane iron almost as a jig to rid the grinder rest, but as mentioned previously, other than early parts of a tool's life (like in making in my case), I will keep the overall geometry with the hones and then use the grinder just to remove metal that is impeding working the edge easiest.

I think a rest for most people will work best - as in one set for the wheel, and then fingers close to the iron bevel for feel, and you can use the opposite hand fingers to create a fence lower on the iron so that it can't lift a little above the rest and waste your time.

yes on the plane irons - I do not generally keep any that are "perfectly straight" across outside of fillister and rebate planes, and perhaps a shooting board plane - but even there it won't matter as much as just setting the plane properly.

But all of the edges that I use to match or strike edges have a small amount of camber. It is on a jointer, perhaps only a few thousandths of an inch, and on a try plane, a little more. By I have had great invisible edge joints off of the try plane without having to go finer. The camber is maintained in honing just by deciding where the pressure will be.

For example, if you are using a jointer and it seems like the shaving is a little narrower than preferred, you make mental note and then work the center of the iron more than the outsides when honing the next time. if it's the opposite, then some emphasis honing the outer areas of the iron a little more next session. Nothing ever really gets away from the ideal set very far, so not much capability is needed then in considering how to get from something out of whack to something good. The same is true for skewed irons like a moving filister - they are honed freehand and if it seems like the angle is getting away from what the sole and bed of the plane want, then the area that's getting a little high, you just hone a larger burr on that side when you hone once or twice and all is well again. And then freehand grind without removing the edge, just the same. there is no great need for any fixturing with a skew then because it only needs a rest like the rest of the tools. The grind will not be used to set an angle, so needing something to set the grind precisely goes away and isn't needed.

David,

Thanks for explaining how to look at what the shaving / plane is doing and then fine tune the blade with honing to make corrections.

I will make it a part of my sharpening.

I think you'll still find your problem solving skills and setting things up useful from a toolmaking and getting tools in shape side of things, though.

Toolmaking is fun.

What we talk about a lot is what shape we have to get tools in. it's really about results even though I did more method describing here than usual. But what isn't discussed often is when you have a tool performing really well, how do you keep it performing well like that. Which is more what I described. There is much work getting a tool there but not that much in keeping it there.