Replies

1. 
   flairwoodworks | May 22, 2008 08:06am | #1

   I've never seen or heard of it before.  The idea of even stone wear is tempting, but I would be concerned with how the UHMW would wear.  Sure it's low friction, but it will wear.  if it dishes or crowns, all your cutting edges will take the shape.  I don't know how securely the blade is clamped either, and I doubt you can camber a plane blade.

   Chris @ www.flairwoodwork.spaces.live.com

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

1. 
   GDH2 | May 22, 2008 08:39am | #2

   Chris -Thanks - your two concerns were the main two questions I asked of Gary Blum by email an hour ago. Cambering a plane blade? I don't know how to make a significant camber with any sharpening system. But I'd love to figure it out and make myself a scrub plane out of my extra #4.

1. 
   derekcohen | May 23, 2008 01:03am | #3

   Whether one chooses to use the upside down Blum boxes (there are two, a fixed and a variable angle), a traditional jig such as a LV or Eclipse (for either a bevel up or bevel down plane blade), or freehand a plane blade ... the rules remain the same ...

   1. Establish a clean primary bevel with a 1000 waterstone - test this by the presence of a wire edge across the blade. Without this you will not obtain a sharp edge.

   2. I prefer to remove the wire edge at this point on the final stone (say a 8000 waterstone). Others might do it at the end.

   3. At this point I grind the camber onto the primary bevel. Using the 1000 waterstone, work the one side of the blade until a wire edge forms. For a smoother, this may only require 4 or 5 strokes. Keep a note of the number. Do the same number of strokes on the other side. Now remove the wire edges with the finishing stone.

   4. Move to a higher grit. If microbeveling, it is possible to go directly to the 8000 stone (I use an intermediatry 5000 stone). Hone the centre of the blade until you get a wire edge. Count the number of strokes to do so. Check the blade to see that all previous grinding marks have been removed in that area. If so, then hone the same number of strokes to each side of the blade. Remove the wire edge, and you are basically ready to go.

   The Blum system (which I have for review} still requires the same attention to detail at each side of the blade as any other method. The only difference is that the blade faces upward, and that the jig allows one to use a smaller honing surface area. I have successfully honed cambers by bearing down and adding extra pressure to the outer edges of the blade.

   The material from which the boxes are made appears resilient to wear.  I have not noticed anything in some 3-4 months.

   I shall have a review completed on the Blum sharpening boxes and two planes, a smoother and a trying plane, in about 4 weeks time.

   For an article on grinding a scrub plane blade, try this

   http://www.inthewoodshop.com/WoodworkTechniques/Grinding%20a%20Scrub%20Plane%20Blade.html

   Regards from Perth

   Derek

1. 
   GDH2 | May 23, 2008 04:06pm | #6

   Derek -You really are a treasure. I've read numerous posts by you that are true tutorials and I've learned a lot from every one. I've read most of the articles on your web site. Thank you for all your effort in general, and for your response to my question.You obviously keep your blades VERY sharp if you START your sharpening with a 1000 stone for the bevel! (Didn't you used to use a belt sander for the bevel?)Thanks for the link illustrating how to put the radiused camber (thank you Chris!) on a scrub blade.FYI, Gary says he has not had any dishing of the top surface but it can be planed if needed.PS - I ordered a sharpening box yesterday - I really need to some sharpening very soon and Gary's 30-day guarantee was the sales clincher.

2. 
   flairwoodworks | May 23, 2008 06:48am | #4

   The Veritas MkII honing guide has an optional cambering roller, though you can add a light camber using nearly any honing guide by putting more pressure on one side, then the other.  However, I would describe a scrub plane blade as being radiused, not cambered.  I sharpen mine with a bench grinder, then clamp it in my vice and go at it with a stone.  It doesn't need to be scary sharp like a smoothing plane blade.Chris @ http://www.flairwoodwork.spaces.live.com

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

2. 
   zolton | May 23, 2008 04:02pm | #5

   I went to the Blum tool site and was quite interested to see their sharpening box product. Not to purchase mind you. I'm way too cheap for that.

   It's a clever idea with some good fundamentals though, and I'm wondering if something like this could be made to produce a planer/jointer knife sharpening jig..

   It wouldn't really take much; just a length of stock cut to a 45 degree angle. The blade could be screwed to the 45 with the leading edge sticking just a bit above the flat part of the jig. Diamond stones would be run along the edge in order to sharpen it, while keeping the stone flat on the top. Sounds pretty simple.

   The resulting edge would be reasonably true, as you wouldn't be removing much steel. You could probably get by between professional grindings once or twice before sending them in to be reground straight again.

   Anyone see anything wrong with this scenario? Is it too simple?

   Zolton 

    

   But it did

   If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon

1. 
   saschafer | May 23, 2008 05:46pm | #7

   I think the concept is sound, although it might be tricky to accomplish in practice. The thing that sets jointer and planer blades apart is the need to maintain an absolutely straight line over several inches. That turns out to be surprisingly difficult to do, unless you have a really heavy-duty reference base that absolutely, positively won't deflect.

   -Steve

    

1. 
   zolton | May 23, 2008 06:06pm | #8

   Steve,

   Being a cheapskate, I was thinking of just stacking a couple of pieces of 3/4 MDF, gluing them together, and cutting the 45 degree bevel on the edge of that. It would be hard to get anything more flat and straight than a top surface of MDF - at least in terms of materials within easy reach. The ideal would probably be a blank of steel or cast iron.

   I've got to sharpen my planer and jointer blades in a week or so, and I'll give it a try. If nothing else I'll learn what not to do..

   ZoltonIf you see a possum running around in here, kill it. It's not a pet. - Jackie Moon

1. 
   saschafer | May 23, 2008 06:37pm | #9

   I just did some computations using the Sagulator: I would recommend laminating four pieces of 3/4" MDF (3" total thickness), at least 4" wide, for adequate stiffness. After the glue has cured, you'll need to double-check the surface for flatness.

   When using it, you can't bear down on the stone, as that will very readily bow the "beam."

   -Steve

    

1. 
   zolton | May 23, 2008 07:33pm | #10

   Steve,

   Wow! All that to support 12 inch planer blades? Maybe I should throw in an I-beam or two under the assembly to insure it stays rigid. No, wait; how about a reinforced concrete foundation, down past frost depth of 42 inches?

   Or maybe my first inclination - to build it of steel - was the more reasonable choice..

   Thanks for the calculations. After the concrete truck leaves and my footings for the pour have time to cure, I'll get back to you with the results.

   Zolton

    If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon

2. 
   flairwoodworks | May 24, 2008 09:50am | #11

   Zolton/Steve,

   What if you put your diamond stone on your jointer bed, set the fence to the reqired angle, and ran the blade along the stone with the beveled face against the fence?Chris @ http://www.flairwoodwork.spaces.live.com

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

3. 
   saschafer | May 24, 2008 03:48pm | #12

   Once again, the difficulty is in maintaining an absolutely straight line. The blade will invariably rock, and being 0.005" out over the length of the blade is too much.

   -Steve