Trouble getting square edges on plane and chisel

Hello mcb,
my apologies for trying to sound technical in my writing, sometimes difficult to explain by the written word and thanks for replying.

When I wrote "I just couldn't get a straight enough edge", I meant the sharpened edge of the blade is not straight at right angles to the blade's long
side edge but is slightly curved so that in use, only the centre area of the blade is doing the work.

The backplate definitley needed replacing but I didn't spot the damage until advised to inspect it by R Sorby. It had ruts in it and was not flat. Wear
from the belts was suspected as I had worked on 4 blades and 7 chisels.

I am, as advised, sliding the blade/chisel back and forth across the belt face, firstly without the guide as freehand which made me think it was my ineptness but later, with
the R Sorby guide. The guide itself slightly jiggels within the guide rail so a good firm grip is needed anyway.  

I work through both course and finer belts as supplied with the machine.

Also, bear in mind that sharpening on pretty much any "jigged up" tool still requires a fair bit of pilot control and intervention. Don't make the mistake of assuming that just because everything is jigged up that you don't need to be an actor in the play so to speak.

To that end when I'm sharpening chisels I get my tiny little marples square and mark a sharpie line right on the tip of the back of the chisel/plane iron. This is then a known datum of a right angle to the long side. This datum wants to be as close to the edge as you can get it because you don't want to grind too much metal off of course. I simply continually eyeball the line as I'm grinding (pilot in play and not just jigs) and adjust my finger pressure if the grind is not exactly following the line.

Your problem with the convex curve (if I've understood you right) was clearly caused by a dipped back plate but now that's resolved my technique above should sort you out.

On the issue of should you microbevel or not. The advice in the good old oil stone days was yes always because its a hell-uv-a-lot quicker to hone a small amount of metal than do the whole bevel by hand I can tell you, youch my fingers hurt!!

Nowadays with the help of tools like the PE and modern abrasives, its more up to you since grinding the whole bevel takes seconds instead of about half an hour of sore manual fingers. Personally, now I'm moving progressively away from curved wheel grinders which leave whats called a hollow ground edge, on to the PE which leaves a flat grind, I'm tending not to do micro bevels because there's no real advantage. With hollow ground bevels you do have the added bonus that you can "touch up" the edge on a diamond plate or stone by hand easily because the edge and the heel of the bevel form a slight arch so the tool doesn't rock when you hand hone it. This makes the ability to hold the appropriate angle much easier as you can feel when its right all without jigs. With a perfectly flat bevel its not as easy and takes more skill and practice.

The fact is, its just so darn quick to touch up an edge using the Trizact belt or another very fine one that I see no need for oil stones any more.

On the issue of the angle, I was always taught (by carpenters) that for regular use your plane blade bevel should be at 25 degrees and the secondary bevel at 30. So if you're not grinding a 2ndry bevel then the whole bevel at 30. However, again, all these rules got invented when it was a bugger of a job to change the angle cos it all had to be done manually. In fact, the best bevel angle is the one that makes sense for the wood you're planing right now. If it's very hard, cyrly maple or some other hideous beast you might want a higher angle, if it's the softest, cheapest Scandinavian Deal then even 20 degree is OK. The sharper angles will plane better but they wont last as long. But with a PE on the bench and resharpening taking about 10 seconds, who cares if the edge doesn't last long?? On that premise I personally tend to have sharper angles, not worrying about survival time of the edge. My staple is a bevel angle of 25 degrees

Hope that helps.

I must say I've not experienced that back plate wear issue you raise and I have realy really mullered my machine with 60g ceramic belts when bringing back from the brink turning club members knackered old 1.5 inch skew chisels!! So I don't understand why that's happening to your metal. I did (after your post) take a straight edge to my back plate to look for wear and tear but found none. Incidentally I do use non RS belts which I buy from a place in Andover that makes them up (I buy in bulk and share the cost with other members of my club) and they work out at about half the price.

I think the only consideration on belts is the mechanism by which they're joined. RS promote the woven nature of their belt joins as being strong, whereas cheaper alternatives may use simpler less reliable methods like an overlapped glue joint. I cant see what that has to do with metal wear though and as for the abrasive side....well if they work...and they're half price.....

I just went to RS's website, clicked on 'Sharpening' went to 'Pro Edge' and opened 'Sharpening Belts' and.....there aren't any, so no help there.